According to ancient Irish history and myth the high kings of Ulster, who ruled from about 1000BCE to 500CE, resided at a place known as Emain Macha. Today that site is called Navan Fort and is located just outside of the town of Armagh in Northern Ireland.
Navan Fort, ancient Emain Macha in what id today Northern Ireland. (Credit: Smithsonian Magazine)
Just how much of those ancient records are history, and how much are myth is often difficult to tell, that’s why the discoveries made by archaeology are so important in helping us to separate fact from fiction. Now a new study of Navan Fort is giving preliminary indications that there are more structures hidden in the soil than previous studies had found, that we’ve literally only just scratched the surface of the archaeological remains at Emain Macha.
Ancient manuscript telling the Irish myth of Cul Dreimhe (The Wild Geese). How much of these stories are based on actual events is unknown. (Credit: The Wild Geese)
The
study was conducted by Queen’s University in Belfast but because the site is a
well known historical and tourist attraction none of the usual digging
associated with archaeology was conducted. Instead the researchers, led by
study authors James O’Driscoll, Patrick Gleeson and Gordon Noble surveyed the
site using high tech, non-invasive tools such as those I described in my post
of 27 June 2020.
The scientists began their work with an aerial mapping of the site conducted by a technique known as LiDAR. The LiDAR instrument uses laser beams similar to those in a bar code scanner to sweep the ground from an airplane in order to construct a point-by-point 3D contour model of the entire site. LiDAR scans are so precise and accurate that small bumps and gullys that are imperceptible on the ground become clearly visible in a LiDAR generated plot. See image below.
(Credit: O’Driscoll, Gleeson and Noble)
Airborne LiDAR scans the ground with a laser beam generating an extremely accurate 3D model of the surface. (Credit: Abhipedia)
Having obtained a LiDAR survey of the entire site the researchers followed up their high altitude study with ground level Magnetic Gradiometry and soil Electric Resistance measurements. See images below.
(Credit: O’Driscoll, Gleeson and Noble)(Credit: O’Driscoll, Gleeson and Noble)
When assembled into one map of the entire site the multiple readings reveal a large number of hidden, subsurface structures within the main outer ring of the fort. See image below.
(Credit: O’Driscoll, Gleeson and Noble)
Of particular interest to the archaeologists was a number of what appears to be two circular structures overlapping each other and forming a figure eight shape. While round houses are typical throughout the ancient Celtic world the purpose of these overlapping figure eights is currently unknown. That’s the problem with the high tech, non-invasive techniques, while they may shown the location and general shape of what’s hidden under the ground they can’t reveal exactly what those structures are nor precisely when they were built and occupied. To answer those questions it is necessary to do some actual digging.
During the Iron Age a typical Irish farmstead would consist of a roundhouse surrounded by a wooden fence. The new survey of Navan Fort has uncovered evidence of many such structures. (Credit: Virtual Visit Tours)
This is not the first time that Navan fort has been surveyed by archaeologists, excavations carried out during 1960s and 1990s discovered the largest known building dating from prehistoric Ireland, a 40m diameter roundhouse. Like Stonehenge in England however Navan fort is important both historically and culturally so any actual digging that takes place there must be carried out sparingly and carefully.
Like Stonehenge, Navan Fort is an archaeological site that is so famous and culturally important that extra special permission is required to disturb it in any way. (Credit: The New York Times)
It was in the hopes of acquiring the funding for actual excavations that the archaeologists at Queen’s University conducted their high tech examination. By first using non-destructive instruments to locate hidden structures the scientists can concentrate on the most interesting areas, hoping to not only get the most bang for their buck but the most discoveries for each shovel full of dirt.
The stories associated with Navan Fort are rooted deep in Irish culture. Most famously the location plays a prominent part in the Ulster Cycle of stories as the home of the hero Cù Chulainn, Conchobar mac Nessa the king of Ulster and Deirdre the most beautiful woman in Ireland.
Known as the Hound of Ulster, Cu is Irish for Dog, Cu Chulain is the hero of a large cycle of myths central to Irish culture. (Credit: Twitter)
Whether of not archaeology can ever provide evidence that those legendary characters ever lived is questionable, but it is the only way we have of learning something about how it was that the people of those times lived.
Without doubt the big news for this month is the successful conclusion of the Space X crew demo 2 manned mission. The mission of astronauts Bob Behnken and Doug Hurley began back on the 30th of May 2020 as their Space X Dragon capsule blasted off from Kennedy Space Center in Florida. The very next day the spacecraft followed up its successful launch by docking at the International Space Station (ISS). For the last two months Behnken and Hurley have served as regular members of the ISS crew with Behnken even participating in two EVAs.
Splashdown of Space X’s demo1 capsule. The safe return of astronauts Behnken and Hurley completes the first manned space mission by a commercial company. (Credit: Space News)The Demo1 capsule safely aboard the recovery ship. Space X intends to reuse their capsules as a part of their program to reduce the cost of space travel. (Credit: Space.com)
The mission of Space X crew demo 2 however was to demonstrate the ability of the Dragon capsule to take astronauts into, and back from space. So in order to complete their mission on the first of August Behnken and Hurley climbed back aboard their capsule and undocked from the ISS. The next day the Dragon fired its retro-rockets to slow its orbital speed so that it could reenter the atmosphere.
The
whole operation went without a hitch; the capsule endured its fiery descent
caused by friction with the atmosphere before first a pair of drogue parachutes
and then four big main chutes brought the capsule velocity to less than 15kph.
The most notable part of the whole reentry procedure was that this was the
first American manned splashdown in 45 years. (The space shuttle you may
recall, landed like an airplane on a runway).
So what’s next for the Space X Crew Dragon spacecraft? Well remember this mission was actually the last of the demonstration missions required by NASA to qualify the Dragon for taking their astronauts back and forth to the ISS. The next mission will officially begin NASA’s Commercial Crew Program with a mission to the ISS. That launch, the commercial crew 1 mission is currently scheduled for 23 October 2020. NASA astronauts Michael Hopkins, Victor Glover and Shannon Walker will be joined by Japanese astronaut Soichi Noguchi for a full six-month tour aboard the ISS.
Official poster for the upcoming Space X commercial Crew 1 mission to the ISS. (Credit: Reddit)
And
NASA and Space X have also just announced the crewmembers for the commercial
crew 2 mission scheduled for the spring of 2021. NASA astronauts Shane
Kimbrough and Megan McArthur will serve as mission commander and pilot
respectively. Japanese astronaut Akihiko Hoshide and European astronaut Thomas
Pesquet will join Kimbrough and McArthur as mission specialists.
And the Space X corporation has even more news to celebrate, on August the 4th the SN5 prototype of Space X’s planned Starship rocket successfully completed its first short powered flight. Now Space X has had its share of problems in previous attempts at this first test flight. While one of the earlier prototype simply collapsed under its own weight several others actually exploded in spectacular fashion. But engineering is trial and error and eventually Space X got it right. Now this first test was only a short 150m hop but if you follow the link below to the youtube video below you’ll see that the rocket was under complete control the entire flight.https://www.youtube.com/watch?v=s1HA9LlFNM0
It sure doesn’t look much like a rocket but it sure flew with more control than any rocket ever! (Credit: New Atlas)
Still, this is only the beginning, the final starship rocket envisioned by Space X founder Elon Musk is projected to be 120m in height, four times that of its SN5 prototype. So there’s still a lot of work still to do before Space X can even begin its long term plans for using the starship rocket for the colonizing of the Moon and Mars.
Artist’s impression of Space X’s eventual starship rocket for travel to the Moon and Mars. (Credit: Techcrunch)
Believe it or not there is some space news that doesn’t deal with Space X. On July 30th NASA launched its latest rover on a mission to Mars. Perseverance will reach the red planet in February, landing in the Martian crater Jezero. Perseverance is the first rover vehicle designed to be able to look for signs of ancient life on Mars. The rover also carries with it a small helicopter as a demonstration model which if successful would become the first man made aircraft to fly anywhere outside of the Earth.
Launch of the Perseverance rover on its way to Mars. (Credit: BBC.com)
Finally there’s good news in the preparations of the Lucy space probe for its mission to the Trojan asteroids scheduled for launch in October of 2021. Despite problems caused by the Covid-19 virus on 27 July the mission planners passed their System Integration Review. This will now allow assembly of the space probe to begin at Lockheed Martin’s Space Systems facility in Littleton, Colorado, where all of the mission systems are to be integrated onto the spacecraft’s main bus. Once assembly is completed testing of the entire probe can then begin.
NASA has to have a patch to commemorate every mission, here’s Lucy’s. (Credit: Twitter)
The
schedule is tight, the mission planners are hoping to use a flyby of Mars as a
gravity boost to speed Lucy on its 12 year mission so if they miss their
October 2021 deadline they’ll have to wait another two years to launch. During
its mission Lucy will visit as many as seven different asteroids making it in
many ways the most complex mission ever attempted.
The sub-atomic physics that I was taught in high school was pretty simple. Atoms were made up of Neutrons, Protons and Electrons. The Neutrons and Protons stayed in the atom’s nucleus, and are given the name nucleons for that reason while the Electrons orbited around the nucleus. We also learned that the Protons had a positive charge, the Electrons a negative charge while the Neutrons were electrically neutral.
The Bohr model of an atom of Nitrogen. This is about as sophisticated as high school science classes will get. (Credit: SlidePlayer)
That was about all you’d learn in class, if you wanted to learn any more you’d have to do outside reading on your own, of which I did plenty. It was from books like George Gamow’s “Thirty Years that shook Physics” that I learned about other particles like the neutrino, muon, pion, Lepton and Delta particles. (Although the science may be rather outdated, I still highly recommend Gamow’s book as a history of Quantum Mechanics!!!) Oh, and I also learned that every one of those particles had an anti-particle, identical in every way to its partner except having the opposite electrical charge.
Thirty Years that Shook Physics by George Gamow. Highly Recommended!!! (Credit: Flickr)
But even as I was attending high school physicists were digging deeper. In fact it was in 1964 that physicist Murray Gell-Mann proposed the quark theory of nucleons. Gell-Mann’s idea was that the Proton and Neutron were composed of three smaller particles called quarks, two up quarks and a down quark made a proton while a neutron was two downs and an up. At the same time the lambda and delta particles were also composed of three quarks but for these unusual particles one of the quarks was a strange quark, a name given to the particle to indicate how little physicists understood it at the time. In Gell-Mann’s theory the pion was also composed of quarks but they were made of a quark anti-quark pair. Meanwhile the electron, muon and neutrino were not made of quarks, they remained elementary, fundamental particles that cannot be decomposed into smaller pieces.
The Gell-Mann model of nucleon structure. Three quarks make a proton or neutron while a quark anti-quark pair make a pion! (Credit: Lumen Learning)
It took physicists more than 20 years to work out the ramifications of Gell-Mann’s theory but by the early 1990s they had a framework called ‘The Standard Model’ that was able to broadly describe the interactions between the particles that they saw in their high energy ‘atom smasher’ experiments. The final piece in the standard model was the discovery in 2012 of the Higgs boson, the particle that gives all other particles their mass.
Robert Higgs standing in front of a photograph of some of the equipment needed to finally discover his Higgs boson. (Credit: Science / How Stuff Works)
The standard model doesn’t answer all our questions however. For example while the Higgs boson does give other particles their mass we don’t understand why those particles have the mass they do. The up and down quarks have roughly the same mass, about 5 times that of an electron but other quarks have much larger masses. At the same time we know that the neutrino also has a mass but one that is so small that we haven’t been able to measure it accurately yet, it’s less than one millionth that of the electron. What sets all of the masses for these different particles, we just don’t know?
The masses, in millions of electron volts (MeV) of some elementary particles. What makes all of these masses what they are is completely unknown! (Credit: Semantic Scholar)
One of the problems not addressed by the standard model is that according to theory the neutron should possess a strong electric dipole, it should act like a strong positive and strong negative charges brought close together, a property that would be easily discovered. In order to solve this dilemma, known as the strong CP problem (for Charge Conjugation / Parity) in 1977 the physicists Roberto Peccei, Helen Quinn, Frank Wilczek and Steven Weinberg proposed a new particle called the axion. This new particle would have a very low mass, like the neutrino on the order of one millionth that of an electron, and hardly interact with other types of particles.
One interesting experiment that might discover the axion. (Credit: Universe-Review.ca)
Even
while particle physicists were trying to make sense of the concept of the axion
astrophysicists and cosmologists heard about the particle and realized that the
axion, if it existed, could be a major component of Dark Matter. With its low
mass the axion would have been created in enormous numbers during the original
Big Bang, and since they hardly interact with other particles they would still
exist. Could the axion be the dark matter that the astrophysicists were
searching for?
Now
predicting new particles is a risky business. If you’re right you’ll become
famous like Wolfgang Pauli with the neutrino or Robert Higgs and his boson. On
the other hand there are dozens of ‘predicted particles’ that have never been
found. And it often takes decades for experimentalists to develop the
technology needed to prove that a particle exists. Pauli predicted the neutrino
in 1930 and it wasn’t proven to exist until 1956. Same for the Higgs boson,
Robert Higgs wrote his original paper in 1964 but the particle was only
officially discovered in 2012.
That discovery is what researchers at the Gran Sasso National Labouratory in Italy hope to accomplish with their XENON1T experiment. The experiment consists of a 3.2 metric ton tank of Xenon gas in what is known as a Time Projection Chamber. Photomultiplier tubes inside the tank detect the tiny flashes of light produced by the interactions and the entire apparatus was constructed deep within a mine beneath the Gran Sasso Mountain in order to shield the experiment from false signals due to cosmic rays.
Main Detector of the Xenon1T experiment being readied for installation. (Credit: LNGS-Infn)
After two years of operation the XENON1T team has now announced the first ever measured evidence for the existence of axions. At a news conference on June the 17th the XENON1T physicists presented their data showing an excess number of flashes in the low energy region. This was exactly the sort of signal that would be expected for interactions with axions produced in the interior of the Sun. According to the announcement the amount of data collected was sufficient for a 3.5 sigma confidence level in the discovery.
Latout of the Gran Sasso Labouratory, now the world’s largest underground physics labouratory. (Credit: Nature)
That 3.5-sigma level is the problem; statistically 3.5-sigma means that there is only a one in 10,000 chance that the excess flashes are simply a matter of luck. Like rolling a pair of dice and getting boxcars three times in a row, something that only happens very rarely, but it does happen. The physics community has agreed that in order to really announce a ‘Discovery’ an experiment must achieve a confidence level of 5-sigma, which means that there is only one chance in 3.5 million that the data is just a statistical fluke.
Scientists express their ‘confidence level’ by using the normal of bell curve distribution. The larger the sigma value the more of the bell is contained, the more confident you are! (Credit: Dummies.com)
So
what do experimental physicists do when their experiment looks like it’s found
something but the data is too small to be certain? Build a bigger, more
sensitive experiment of course. The scientists at XENON1T are already doing
just that, upgrading their equipment to an 8 metric ton container of Xenon for
a new 5-year run that should be able to cross the magic 5-sigma threshold.
So
has the axion been found? Well some other physicists are already criticizing
the whole setup; the same signal could be produced by the detector being
contaminated by the isotope of hydrogen called tritium. It takes time to be
certain so we’re all just going to have to wait. Making a discovery is what
every scientist dreams of but as they all know, it’s more important to be right
than to be first!
On the 23rd of July 2020 at 0441 GMT China successfully launched the Tianwen-1 Mars probe from its Wenchang Satellite Launch Center on the island on Hainan. Scheduled to arrive at the red planet in February 2021, Tianwen-1 is China’s first solo Mars mission and a very ambitious one at that. Combining an orbiter, lander and rover, if Tianwen-1 is a complete success it will leapfrog China, formally the People’s Republic of China or PRC, into a leading position in planetary exploration.
Liftoff of China’s Tianwen-1 space probe on its way to Mars. (Credit: The New York Times)Artists impression of the Tianwen-1 lander preparing to deploy its rover onto the Martian surface. (Credit: BOL News)
The launch of Tianwen-1 comes just a year and a half after China’s successful landing of their Chang’e-4 probe onto the surface of our Moon. Chang’e-4 was the PRC’s second lunar lander and the first by any nation onto the Moon’s far side. Chang’e-4 also deployed a small rover onto the Lunar surface that is still operating, setting a record for continuous operation by a robotic rover on the Moon.
The Chang’e 4 lander (l) and rover (r) on the lunar surface. (Credit: NSSDCA – NASA)
And it was only back in 2003 that China became just the third nation to successfully carry out a manned space mission. Shenzhou -5 was the first of six missions to date in a continuing series, each of which is designed to step by step increase China’s skill and capability in space. The last three of China’s manned missions in fact succeeded in docking with an unmanned Tiangong space labouratory module, similar to the Russian Salyut from the 1970s, giving China useful experience in operating and maintaining a space station.
China’s manned space capsule Shenzhou bears more than a slight resemblance to Russia’s Soyuz. (Credit: Zee News) The Shenzhou capsule (upper left) docked with the Tiangong space labouratory. (Credit: The Australian)
The PRC government in Beijing has shown considerable and steady support for its space program. In China their successes in space are a much publicized source of national pride as well as being considered a key element of the nation’s future as a leader in technological development. With China’s growing wealth and power it seems certain that the country’s space program will continue to grow as well.
So,
what are the PRC’s future plans for space? And is this the beginning of a new
space race with the United States?
To
answer these questions it is important to recognize the difference between
long-range goals and those programs to which a strong commitment has been made,
in other words those programs that are getting the funding. Officials with all
national space programs often talk about the mission plans they would love to
be working on, but few of these plans ever make it past the drawing board.
With
respect to manned spaceflight Chinese officials have often spoken about their
intentions for a manned Lunar mission sometime around 2030 with a permanent
Lunar base to come sometime after that. At present however neither the large
launch rocket needed for a Moon mission nor a manned lander to put Chinese
Taikonauts on the Moon’s surface are in development.
Currently China’s manned efforts appear to be focused on the construction of a space station similar to the USSR’s old Mir station. China’s next five manned space missions are all dedicated to this endeavor with construction scheduled to start in 2021 and lasting through 2023. It seems likely therefore that China’s manned space program will be rather occupied for the next half dozen years or more.
Artists impression of China’s planned Tianhe space station. Construction is scheduled to begin next year (2021) and should take several years. (Credit: YouTube)
As far as unmanned, robotic space probes are concerned China intends to build on the success of its Chang’e series with the Chang’e-5 lander that will collect and send samples of the Moon back to Earth. The success of that mission would make China only the third nation to succeed in returning Moon rocks. There are also plans to carry out a similar sample return mission to Mars. The time frame for the Mars return mission is sometime around 2030.
The mission profile for the planned Chang’e 5 space probe is very complex and if successful will make China only the third country to bring pieces of the Moon back to Earth. (Credit: The Planetary Society)
Longer term robotic missions that have been mentioned by Chinese officials include a probe to Jupiter and its Moons as well as a possible probe to Uranus. If either of those missions ever come to pass it would make China only the second nation, after the US, to send a probe to the outer Solar System.
NASA’s Pioneer 10 probe to Jupiter, launched in 1972 was the first probe to travel beyond the orbit of Mars. To this day no other country have managed that feat! (Credit: NASA)
So are China and the US headed for another space race? Well if you look at the situation reasonably there’s no technical or scientific reason to once again turn space exploration into a contest. There is more than room enough in our Solar System for both countries to conduct a great deal of exploration without stepping on each other’s toes.
America won the first Space Race, but do we really need to have a second! (Credit: Pinterest)
We
humans are a competitive bunch however. Whenever two people, or groups of
people try to achieve the same thing we have to make it a challenge to see who
does it first or better. While a new space race, to put a man on Mars for
example, might serve to increase interest in space exploration temporarily,
once the race was won it could also lead to the same falling off of attention
as happened after the Apollo Moon landings.
China has progressed with their space program in a slow, steady, step by step fashion, unlike the US. You don’t think maybe they could be on to something do you?
Last night, after I had switched off the light in my bedroom and before I could get into bed I saw a small, brief glow of light only about a meter in front of my face. A firefly, Photuris lucicrescens, had somehow gotten into my bedroom.
The firefly Photuris lucicrescens is a well known example of bioluminescence. (Credit: Bruce Marlin)
Now
I’ve a lot of experience in handling fireflies going back about sixty years now
so I quickly, and carefully caught the little guy and released him back outside
where at least a dozen of his friends were waiting for him. But it got me to
wondering, why was I so nice to a firefly when any other bug or spider that
gets in my house I’ll just swat or squish.
It’s bioluminescence, that small glow that gives fireflies their name that makes them pretty to us. Catching fireflies on a warm summer’s night is a game no child can resist but even as a child I would always let the creature go after playing with it for a few minutes. The fact that a living creature, a small insect can generate light within its body mystifies and delights us.
Deep Sea angler fish use a bioluminescent lure to attract their prey! (Credit: Google Sites)
Bioluminescence occurs in a wide range of living things both aquatic and terrestrial. Everything from bacteria and fungi to molluscs, arthropods and even species of vertebrates have shown bioluminescence. Although many creatures, like the firefly produce their light using their own metabolism there are other animals, such as the deep-sea anglerfish, who obtain their light by growing bioluminescent bacteria within their bodies. Bioluminescence is so spread out, here and there across so many different kinds of living things, at least 11 different animal phyla and several of fungi and plants that biologists are convinced that the ability of a living thing to produce light has evolved independently more than 40 times in the history of life.
Many species of jellyfish are bioluminescent. (Credit: Hakai Magazine) Bioluminescent glowworms in caves attract their insect prey to their sticky lines by their glow! (Credit: New Scientist)
Because there is such a wide diversity of living things that produce bioluminescence the early study of the phenomenon concentrated on individual species rather than examining it as a single subject. While both Aristotle and Pliny the Elder discussed the glow produced by damp, dead wood it wasn’t until centuries later that Robert Boyle showed that the gas oxygen played a major role in producing the light. And even then it took more than another hundred years, until 1854, that Johann Florian Heller finally discovered that it was actually a fungus growing in and consuming the wood that was producing the light.
Many species of mushrooms and other fungi are bioluminescent. (Credit: Time for Kids)
At about the same time Charles Darwin suggested that the bioluminescence often seen in the tropical ocean capping crests of waves and illuminating the wakes of ships was due to ‘minute crustacea’, one of the few times he was wrong in his hypothesis. The greenish light that is produced in disturbed ocean waters is in fact caused by several species of dinoflagellates in the plankton.
Bioluminescent waves at night are caused by billions of single celled plankton. Whatever causes then they are still mysteriously beautiful. (Credit: Treehugger)
It is really only since the mid 20th century that the chemical processes that generate bioluminescence have been adequately described. Simply put the chemical reaction involves an organic pigment referred to as the luciferin, which is induced to emit light by an enzyme called the luciferase. Problem is that there are so many different chemicals that living things use as their luciferin and luciferase that the only thing that can be said about the reactions in general is the use of oxygen as the source of energy. The fact that so many different chemical reactions can produce bioluminescence is undoubtedly one of the reasons that the ability has evolved independently so many times.
One of the many biochemical reaction that will produce light. (Credit: photobiology.info)
And with so many different kinds of living things using bioluminescence it’s hardly surprising that they use it in a wide variety of different ways. It is well known that the fireflies in my backyard use their glowing tails as a means of attracting a mate; it’s only the male who does the blinking by the way. Deep-sea anglerfish on the other hand use their bioluminescence as a lure to draw smaller fish in close so that they can then eat’em.
Those
are two of the more straightforward uses of bioluminescence; some others are
not so obvious. For example the glowing of fungi in damp, dead wood that
Aristotle noticed. It is thought by some naturalists that the glow might cause
insects or animals to come and investigate, the fungi then is able to spread
some of its spores onto the animal’s skin, feathers or fur. Those spores may
then be able to pass on to other dead, damp pieces of wood allowing the fungi
to propagate.
Many species of cephalopods, squid and octopi use bioluminescence as a defensive measure. Whenever they feel threatened they will squirt out a cloud of bioluminescent material that startles and blinds the attacker allowing the cephalopod to escape, sort of the exact opposite of the black ink used by other cephalopods for the same reason.
This bioluminescent squid, Abralia veranyi, uses the lights on its belly as a form of camouflage, animals beneath it assume the light is coming from the sky above the surface. (Credit: PBS)
Since we humans have always been intrigued by bioluminescence it’s not surprising that genetic researchers have been playing around with the genes responsible. As far back as 1986 the firefly gene that produced its version of luciferin was successfully implanted into tobacco plants. Currently there is a considerable amount of research underway to see if bioluminescent bacteria can actually be used to manufacture a form of living light bulb. Such a light bulb would not require electricity to generate light but as you might guess the greatest difficulty at present is the low light intensity, the low amount of energy in other words.
Bioluminescent lightbulb! The bacteria in this bulb don’t produce a great deal of light but they do so without electricity! (Credit: ScienceBlogs)
Whether or not any of these experiments manage to develop something that is practical, something of commercial value is questionable at the moment. Still bioluminescence has always fascinated us, so much so that scientists will keep on studying it, if only for a bit of fun.
The Atacama Desert of northern Chile is situated on a broad plateau between the Andes Mountains and the Chilean coastal range. Being at an average elevation of 3,000m and surrounded by two high mountain ranges little moisture reaches the Atacama so that it has been measured as being the driest place on Earth with the possible exception of some areas in Antarctica.
Not only is the Atacama Desert bone dry but many areas are salt flats making it even more hostile to life. (Credit: Live Science)
With an average annual rainfall of about 15mm you shouldn’t be surprised that there is little life in the Atacama, vegetable or animal. While those parts of the Atacama that receive some moisture are home to several species of cacti and saltgrass along with insects, scorpions and even a few lizards there are areas where the desert is so arid that no life can survive for very long.
Although several species of lizards inhabit the Atacama their population is extremely low. (Credit: Atacama Photo)
However
there is one form of life that recently has begun to rapidly multiply in the
Atacama Desert, scientists, particularly the sub-species astronomers. In fact
the very extreme nature of the climate in the Atacama is what has many
scientists excited, even anxious to work there.
NASA scientists are interested in the Atacama because it is the region of Earth that most closely resembles the conditions on Mars, cold, dry and at 3,000m altitude even the air is thin. In fact a team from NASA duplicated the tests for life that had been performed on Mars by the two Viking landers and got the same results as the Vikings, no life. NASA has also used the Atacama on several occasions to test various instruments for several of their Mars landers.
If you want to test your Mars rover in realistic conditions the Atacama is the best place on Earth to do so. (Credit: MIT Technology Review)
But
it’s the astronomers who really love the Atacama. The thin, dry almost cloud
free air of the high desert along with the lack of city lights of any kind make
it one of the best places on the surface of the Earth for viewing the Universe.
Three large observatories have been built and are being operated by the
European Southern Observatory (ESO). The United States by the way has built and
maintained its largest observatories either on top of the Mauna Kea volcano in
Hawaii or the mountains of the desert southwest.
Although the Atacama Desert has been used for astronomical observations for more than a century the first permanent observatory there was the ESO’s La Silla observatory that began operations in 1964. Currently La Silla operates 10 medium to small telescopes including the 3.6m New Technology Telescope that back in 1984 was one of the earliest telescopes to employ adaptive optics.
The La Silla Observatory features a half dozen instruments for observing the Universe. (Credit: Britanica)
The largest optical telescope in the Atacama, indeed the second telescope in the world is the Very Large Telescope (VLT) at the Paranal Observatory. The VLT actually consists of four 8.2m telescopes whose light is ‘added together’ by means of computer controlled optics. This ‘adding together’ of the light from the four large telescopes effectively makes them into a single huge instrument. (Let me tell you a little secret. I understand the math used to perform this magical feat but I freely admit that the precision needed to do this accurately at optical frequencies makes my head swim!)
The Very Large Telescope at the Paranal Observatory is actually four identical ‘scopes whose light is combined to make them the 2nd largest telescope in the World. (Credit: Wikipedia)
In
addition to the four main telescopes the VLT also possesses four smaller 1.8m
telescopes that are located at a distance from the larger ‘scopes. The light
captured by the smaller instruments can also be added to that of the big
telescopes allowing the VLT to conduct interferometric measurements of
astronomical objects.
The third observatory in the Atacama Desert is the Llano de Chajnantor, a radio observatory specializing in studying the Universe in millimeter and submillimeter wavelengths. In fact because water vapour in the air effectively blocks such high frequency radio and infrared light the arid Atacama Desert is really the only place on Earth’s surface where such an observatory could be built. The main instrument at Llano de Chajnantor is the Atacama Large Millimeter Array, a collection of 54 12m-radio dishes whose signals are again added together to make them act as a single instrument. (Performing this operation at radio frequencies is much easier; in fact I have worked on such adaptive arrays many times in my career.) Also at Llano de Chajnantor is a single 12m-submillimeter dish one of the few instruments in the world working at such high frequencies.
Part of the array of radio dishes at the Llano de Chajnartor observatory. The Atacama is one of the few locations where such high frequency radio observations can be made. (Credit: Taipei Times)
So that’s a brief description of the observatories and instruments expanding our knowledge of the Universe currently operating in the high Chilean desert. Today there are actually so many astronomers working in the Atacama that they even have their own hotel there.
The hotel exclusively for astronomers is located near the Paranal observatory. (Credit: Modlar)
And there’s more to come. The ESO’s Extremely Large Telescope (ELT) is now under construction at the new Cerro Armazones Observatory. When completed the ELT will have a primary objective 39.3 m in diameter making it the largest optical telescope in the world by a considerable margin. The telescope is expected to be completed and begin observations, a moment that astronomers like to refer to as ‘first light’, in 2025.
Artists impression of what the Extremely Large Telescope will look like upon completion. (Credit: Wikipedia)
Right
now we can only guess what kind of discoveries that instrument will make. All
of this astronomical activity clearly shows that the future of the Atacama
Desert as a haven for scientists is only beginning.
Most people are familiar with the Search for Extraterrestrial Intelligences (SETI) program, the scientific endeavor to use radio telescopes here on Earth to detect transmissions that might be coming from alien intelligences in other solar systems. While some attempts at SETI research date back to the very early days of radio it was in 1980 that Carl Sagan, Bruce Murray and Louis Friedman founded the Planetary Society which has served as a focal point for SETI research. Despite many years of searching thousands of possible nearby stars to date the SETI program has failed so far to find a single signal that is unequivocally from an alien intelligence.
The founding of the Planetary Society, organized for the purpose of SETI research. Clockwise from lower right, Carl Sagan, Bruce Murray, Louis Friedmann and Harry Ashmore. (Credit: Wikipedia)
Our Galaxy is a big place however, and for every star that has been observed looking for intelligent signals there are thousands that have not. In other words the work of SETI has barely begun. In fact its hardly surprising that, in a Galaxy filled with literally billions of worlds where life could exist our first few attempts to find it should come up empty.
Impressive as it is we only see a small fraction of all of the stars of our Milky Way Galaxy. (Credit: Space.com)
So the scientists at SETI did what scientists always do when they need to expand their search efforts in order to obtain more data. Develop a broader search program, design more sensitive equipment, and look for more funding.
The Allen Telescope Array made up of 42 radio dishes in Northern California is one of the projects funded by SETI. (Credit: Phys.org)
Enter the Breakthrough Initiative. Breakthrough is the brainchild of Russian Billionaire Yuri Milner who is funding a series of high-risk scientific studies that have the potential to revolutionize human society if any one of them should succeed. In other words Milner expects most of his initiatives to fail but he’s hoping for at least one Breakthrough!
Breakthrough Initiative founder Yuri Milner announcing his project. The late physicist Stephen Hawking in the background was an adviser to Milner. (Credit: Astrobiology Magazine)
The Breakthrough Initiative’s contribution to SETI comes in the form of a $100 million dollar grant called Breakthrough Listen that is being managed by the SETI Research Center at the University of California at Berkeley. The large size of that grant has allowed the Breakthrough Listen team to obtain time on several of the biggest radio telescopes including the 100-meter fully steerable telescope at Green Bank Observatory in West Virginia, the world’s largest, and the 64 meter telescope at Parkes Observatory in New South Wales Australia. By taking observations from one radio dish in the northern hemisphere and one in the southern the scientists are able to study the radio emissions coming from any star in the sky.
The Robert Byrd 100m radio telescope at Green Bank Observatory. I did a bit of work on the design of this baby! (Credit: Wikipedia)the 64m Parkes radio telescope in Australia. (Credit: Wikipedia)
Even with that extra funding and better instruments however Breakthrough Listen still has an enormous amount of work to accomplish. In an effort to concentrate their efforts on the most likely targets the Breakthrough Listen astronomers have begun listening to stars that are known to have planets thanks to the efforts of the Kepler Space Telescope. In my post of 28th April 2018 I discussed how the Kepler Space Telescope succeeded in discovering more than 2500 planets around other stars by measuring the small drop in the star’s brightness as one or more of its planets passed in front of it. The breakthrough Listen team can now make use of Kepler’s results in order to thoroughly examine those stars known to have planets before continuing on to other targets.
NASA is quite proud of their planet hunting Kepler Space Telescope, with good reason. (Credit: Phys.org)
In fact we might even think in reverse and first consider examining those stars where the inhabitants, if any, could see the Earth and the other planets of our solar system crossing in front of the face of our Sun. The possible alien civilizations around those stars might actually have already discovered Earth and be trying to contact us at this very moment! The stars that fit that criteria are those that lie along or near the plane of the ecliptic, the path the Sun takes through the background stars every year.
As viewed from here on Earth, the Sun and the planets seem to move across the constellations along a line called the Ecliptic. In reality the Earth and the other planets orbit the sun in a plane called the ecliptic. (Credit: Space.com)
This
new search effort was conceived by and is being led by Sofia Sheikh, a graduate
student at the Department of Astronomy and Astrophysics at Penn State
University. To date the team has accumulated and released over four petabytes
worth of data but sadly no definitive signal from any aliens. Ms. Sheikh and
the other Breakthrough Listen scientists will keep at it however; after all
there are only another 200 billion stars in our Milky Way left to examine.
And if you think about it, isn’t that the whole idea behind the Breakthrough initiative? To invest in research that has little chance of success, but will change the world if it does?
Many common backyard birds throughout the world are known for the beauty of their calls giving them the common title of songbirds. Each species has its own particular call which are so distinctive that many experienced ‘birders’, that how bird watchers prefer to be referred to, can often tell you what species of bird is singing off in the bushes without ever getting a glimpse of the singer. In some ways the song of a species is as distinguishing as the colours of its feathers.
Any birder worth their salt would recognize a yellow warbler as easily by their song as their appearance. (Credit: PRDseed.com)
It’s the male birds that do all the singing, using their calls to announce their territory or attract mates and birdcalls are known to change very little over time. Nevertheless the song each species of bird uses is not instinctive, every generation of males must learn the song and therefore over time change will occur, however slowly.
That’s why Ken Otter, Professor of Biology at the University of Northern British Columbia was so surprised when he moved to the city of Prince George in the 1990s. While getting acquainted with the local fauna Dr. Otter discovered that the white throated sparrow ( Zonotrichia albicollis) population west of the Rocky Mountains used a two-note ending to their song quite unlike the three-note triplet that ended the songs of white throated sparrows throughout the rest of Canada.
A male White Throated Sparrow. (Credit: Hickory Knolls Discovery Center)
The female White Throated Sparrow. As is usual for songbirds the female’s colours are drab compared to those of the male. (All About Birds)
Intrigued Professor Otter discussed this new song style with several of his colleagues and together they decided to try to track the spread of the new two-note ending. In order to obtain as much field data as possible the naturalists contacted amateur bird clubs and organizations across Canada, enlisting the help of hundreds of volunteers. These field researchers used their cell phones to record the songs of white throated sparrows in their area and sent the recordings to Professor Otter who added them to his database.
Birders in action. They may look a bit crazy but they’re pretty harmless! Actually they are an enormous army of eager volunteers for doing the legwork of scientists studying nature. (Credit: Michigan Audubon)
With the huge number of recordings accumulated over 20 years by his volunteers Doctor Otter was able to observe the spread of the new song as bit by bit it moved eastward, reaching Alberta in 2004 and Ontario ten years later. So comprehensive is the data that Professor Otter was able to show that younger, juvenile males were learning the new song at the sparrows overwintering grounds and then taking the new song with them as they returned to their summer homes. So while Professor Otter and his colleagues may not be the first scientists to observe a change in the song of a species of songbird they have succeeded in developing the most extensive map of a cultural shift in a species of bird ever obtained.
Dynamic analysis of a nightingale’s song. Scientists can learn a great deal by such studies of birdsong. (Credit: Semantic Scholar)
Still one question remains, why did the new two-note ending so rapidly replace the old, traditional three-note ending? Doctor Otter can only speculate that female white throated sparrows might prefer the novelty of the new song. As the professor put it, “…we might find a situation in which the females actually like songs that aren’t typical in their environment. If that is the case, there’s a big advantage to any male who can sing a new song type.”
Male birds complete for females in many ways, often by their song! (Credit: Pinterest)
Cultural
change being driven by males trying to attract females who are seeking some
novelty in their lives, sounds quite human to me.
Before I go I’d like to take a minute to update a post I published back on the 4th of January 2020 about a significant dimming in the light coming from the star Betelgeuse, normally the 10th brightest star in our night sky. Betelgeuse is a giant red star that is nearing the end of its life and is expected to explode as a supernova in the near future. Near future for a star being sometime in the next 100,000 years.
The constellation of Orion the hunter. Betelgeuse is the bright red star on the hunter’s left shoulder. (Credit: MilkyWayPhotographers)
While the energy output from Betelgeuse has been unstable ever since astronomers began making precise measurements of it more than a century ago the decrease that was observed late last year was unprecedented leading some astrophysicists to speculate that the star’s end might be near. However so far in 2020 the star seems to have stabilized itself leading astronomers to wonder what had caused the dimming.
Comparison of Betelgeuse over less than a year’s time. Despite the fuzziness of the images the growth of the starspots is obvious. (Credit: Forbes)
Now
a group of astronomers at the Max Planck Institute for Astronomy have announced
that they have discovered the direct cause of Betelgeuse’s drop in brightness.
The team, led by Dr. Thavisha Dharmawardena have found that 70% of the star’s
surface is now covered by Starspots presumed to be similar to the Sunspots on
our own Sun. While Starspots have been detected on other stars before none have
come anywhere close to being as extensive as those now seen on Betelgeuse.
So now the question is, if the Starspots are the
cause of Betelgeuse’s drop in brightness, what is causing the Starspots? And
are those Starspots a prelude to an imminent explosion? Keeping in mind that
imminent for a star could still mean sometime in the next thousand years.
A little more than 100,000 years ago our species Homo sapiens only existed on one continent, Africa. Yes we had some relatives who had already moved out into other lands. Neanderthals were living in Europe and Homo erectus, ‘Peking Man’ inhabited Asia, but the new species H sapiens had yet to spread out from the land of its origins.
Human Migration around the World. Out of Africa about 100,000 years ago and now we occupy the entire land mass of the Earth! (Credit: ResearchGate)
Since
that time we have spread out, migrating to every continent so that today human
beings live in every climate from artic ice to tropical rainforest to arid
desert. As a species we have always gone as far as our technology would take
us, settling every piece of inhabitable land we could find.
Certainly some of the most ambitious, courageous migrations ever have to been accomplished were by the Polynesian mariners as they sailed their small, wooden, two hulled ships across the Pacific. With no instruments of any kind, nor any maps to follow they nevertheless succeeded in spreading their culture across the world’s largest ocean. In some ways those voyages were a prelude to our modern space explorations when you consider how tiny those islands are and how vast the ocean distances between them.
The voyages undertaken by the Polynesians may be little known but they were among the most epic ever attempted by humans. (Credit: Twitter)
We know that the Polynesians sailed eastward from the coasts of Asia as far as the Hawaiian island chain and the lonely island of Rapa Nui, formally known as Easter Island. The current consensus among anthropologists however is that’s as far as they got. Even those intrepid navigators never managed to completely cross the Pacific; they never discovered the Americas.
Starting about 3000 BCE the migration of the Polynesians spread across the world’s largest ocean. (Credit: Ancient History Encyclopedia)
That’s the consensus; there are a few researchers who disagree however, who consider the idea of contact between the Polynesian islanders and the Native Americans as being not only possible but highly likely. For decades they have searched for evidence of that contact. To date the most convincing evidence they’ve found is the widespread use of sweet potatoes, a plant native to South America, throughout Polynesia. Now those scientists are trying to find more evidence using DNA.
Did the Polynesians get the sweet potato from South America while the South Americans got chickens from the Polynesians? (Credit: The Honolulu Advertiser)
Doctors, and spouses Karla Sandoval, an anthropologist and Andres Estrada, a geneticist both with the National Labouratory of Genomics for Biodiversity at Irapuato in Mexico, spent several decades assembling a comprehensive catalogue of the genetic makeup of modern Latin American ethnic groups. Using this catalogue as a database in 2013 the scientists began a study of the genetic makeup of 809 people from Rapa Nui and other Pacific Islands searching for evidence in Polynesians of DNA from the Americas.
The Island of Rapi Nui, famous for it enigmatic statues, was the farthest island settled by the Polynesians. Or was it? (Credit: University of Oregon)
In
doing their analysis Sandoval and Estrada faced a very big problem. You see
over the last 250 years the Polynesian people have had considerable contact
with both Europeans and South Americans. Rapa Nui for example was annexed by
the South American nation of Chile in 1888. In order to find any earlier DNA
that would indicate contact between Polynesia and the Americas they had to
eliminate those Polynesians who carried both South American and European DNA.
In
the end the scientists did succeed in finding six individuals whose DNA showed
no sign of European genes but who did possess strands of DNA that are nearly
identical to those found in the ethnic Zenu tribe in Colombia. Based on the
size of the DNA strands Sandoval and Estrada were even able to estimate that
the contact took place some 800 years ago, long before Columbus and the
European age of exploration began. Is this then the missing piece of evidence
to prove that there was contact between Polynesia and South America?
There are some who are not yet convinced. Biological Anthropologist Lisa Matisoo-Smith of the University of Otago in New Zealand points out that since both Polynesians and Native Americans are descended from an original Central Asia people the analysis must be expanded to include people from China or Mongolia in order to make certain that the DNA strands in question aren’t in fact more than 10,000 years old.
One scenario by which Polynesians and South Americas could have intermingled. (Credit: Daily Mail)
Even
if further DNA studies do prove that Polynesians contacted South Americans
around 800 years ago such studies still won’t be able to answer the question of
who contacted who. Did a few Polynesian catamarans make it to Colombia and
return to their islands with a few members of the Zenu tribe or did the South
Americans sail out into the Pacific and meet the Polynesians halfway?
Back in 1947 Norwegian explorer and anthropologist Thor Heyerdahl tried to demonstrate how it could have been the South Americans who actually settled the Islands of the Pacific. He did so by building a small raft in Peru using only pre-Columbian technology and in accordance with descriptions of native rafts by Spanish conquistadors. Naming his vessel the Kon-Tiki after an Incan god Heyerdahl and his crew of five then sailed some 6,900 kilometers westward across the Pacific proving that the peoples of South America could have reached the islands of Polynesia.
The voyage of the Kon Tiki may have made Thor Heyerdahl famous but few anthropologists accept his theories. (Credit: IMDb)
In a sense of course it doesn’t matter which way the voyages went. The settlement of the Islands of the Pacific are a clear demonstration that we humans are explorers, travelers. That we belong wherever it is we choose to go!
There
are a number of small items to discuss this month so let’s get started.
First of all, things continue to go smoothly for Space X’s first manned mission to the International Space Station (ISS). Astronauts Bob Behnken and Doug Hurley have been on the ISS for more than a month now, assisting the regular crew in their maintenance and repair work. Bob Behnken even got to perform an EVA with his fellow American astronaut Chris Cassidy in order to replace a number of the station’s external batteries.
The Space X Dragon capsule attached to the ISS as photographed by astronaut Bob Behnken during his EVA. (Credit: Teslarati.com)
Although
NASA has yet to announce exactly when Behnken and Hurley will return to Earth
in their Dragon capsule they are probably about halfway through their mission.
Before they leave however NASA plans on conducting some kind of emergency
station test using the Space X Dragon capsule as a part of the test.
The idea is to pretend that a disaster to the ISS forces all five members of the crew, the three Americans plus two Russian cosmonauts, to use the Space X Dragon capsule as a lifeboat. Now the capsule will not actually undock from the ISS. It will however be quickly woken up and brought back to operational status. All five crewmembers will climb aboard the capsule and remain there for several hours, simulating a real emergency.
The current five member crew of the ISS will participate in an emergency drill using the Dragon capsule as a potential lifeboat. (Credit: Positively Osceola)
Continuing with manned spaceflight NASA has announced the results of their analysis of the problems that occurred during the unmanned Orbital Test Flight (OFT) of Boeing’s Starliner capsule back in December 2020. During that flight a software problem occurred that caused the spacecraft to carry out the wrong maneuver, using up so much fuel that it was unable to rendezvous with the ISS. The capsule was able to return safely to Earth but an initial review of the mission revealed several other serious software issues that went unnoticed during the actual test flight.
The launch and landing of the Boeing Starliner capsule went perfectly on its unmanned test flight. The problems all occurred in between! (Credit: Space.com)
Based
upon their review NASA engineers have made a total of 80 recommendations to
Boeing that the aerospace firm must address before a second, unmanned OFT can
be conducted. Boeing hopes to implement the necessary changes quickly, in fact
the engineering effort is already well underway, with an eye towards a launch
date late this year for the second OFT.
That would allow Boeing to conduct their first manned flight with Starliner early next year. Once that flight has taken place the US will for the first time ever have two operational space systems for getting astronauts into orbit, both owned and operated by commercial corporations.
In just a couple of years NASA hopes to have three capsules taking their astronauts into space. Here are Orion, Dragon and Starliner (CST-100) compared to the Apollo command module. (Credit: Quora)
NASA also hopes that next year will see the first, unmanned test launch of the long awaited Space Launch System and Orion capsule, a launch vehicle that will not only take astronauts into Earth orbit but beyond. The SLS is in fact the foundation of NASA’s Artemis program with its ambitious goal of returning Americans to the Moon by the year 2024. Pieces of the first SLS rocket are finally, many years behind schedule starting to arrive at Cape Kennedy for assembly with an intention of the initial test launch of the whole rocket sometime in 2021.
If SLS block 1 is ever completed, it’s already five years behind schedule, this is what it will look like on the launch pad. (Credit: NASA)
The Artemis goal of putting Americans back on the Moon is more than just ambitious; it’s expensive. So when on July 7th the US House of Representatives Appropriations Committee released its funding bill for NASA it could only be considered disappointing. As announced the funding for NASA in 2021 will remain at exactly the same level as in the current fiscal year, $22.63 billion dollars. In other words there is no new money of any kind for Artemis.
The House Appropriations Committee in action. With all of the money being directed to fight the Covid-19 pandemic there’s little desire to increase NASA’s budget. (Credit: LegBranch)
That
figure of $22.63 billion is about $3 billion less than NASA requested and the
worst part is that the monetary shortfall comes from the budget earmarked for
the design and development of a new lunar lander, the major piece of hardware
currently not yet under construction. Now the budget bill has not yet been
passed by congress, more money could be added before it is passed. And even if
the budget isn’t increased NASA could undoubtedly divert money from other
projects in an effort to keep making progress on the lander.
Nevertheless
the Artemis schedule was very tight to begin with and without some real support
in congress it is likely that a return to the Moon could, like all of NASA’s
manned deep space proposals over the last 30 years, be underfunded and delayed
until it just dies.
My final item for today deals not with NASA’s manned space efforts, but rather with its more successful robotic exploration probes. Back on the 6th of January in 2017 I posted an article about a couple of new NASA missions intended to explore several of the asteroids orbiting the Sun in the belt between Mars and Jupiter. One of these missions is called Psyche after the metal rich asteroid that is its target.
Just this month the engineering team at the Jet Propulsion Laboratory designing Psyche completed their work and the final design has been approved. This means that work on the spacecraft’s hardware can begin with full assembly and testing to begin in February of 2021.
The design phase of the Psyche space probe is completed but the spacecraft must be built quickly if it is to launch in 2022. (Credit: MarketWatch)
The
schedule for Psyche is tight. The spacecraft must be launched in August of 2022
if it is to use a gravity assist from Mars in order to reach its target.
Arrival at Psyche will then be in early 2026.
