Month: July 2023

Movie Review: Oppenheimer

Any regular reader of this blog would have to expect that I would be seeing, and reviewing the new film ‘Oppenheimer’ as soon as possible. After all, the development of the atomic bomb, and the man (played by actor Cillian Murphy) who directed that development, are watershed moments in the history of science in general, and physics in particular.

Poster for the Christopher Nolan film ‘Oppenheimer’. (Credit: Goelevent.com)

Now, ‘Oppenheimer’ is not the film industry’s first attempt at telling the story of the Manhattan Project, to use the code word for the building of the first nuclear weapon. Shortly after World War 2 the film ‘The Beginning, or the End’ was the first while two other notable efforts are ‘Fat Man and Little Boy’ along with the TV movie ‘Day One’. There’s even a grand operatic telling of the story, ‘Doctor Atomic’ by the composer John Adams.

In the opera ‘Doctor Atomic’ Oppenheimer is a tenor while General Groves is a bass. Still it’s another version of the story of the bomb! (Credit: IMDb)

Those movies concentrated on the building of the bomb however while ‘Oppenheimer’ deals much more closely with the man. Based upon the book ‘American Prometheus’ by Kai Bird and Martin Sherwin, Christopher Nolan’s film includes portions of Oppenheimer’s life both before the war, and more tragically after.

Cillian Murphy plays Oppenheimer in the movie based upon the book ‘American Prometheus’ by Kai Bird and Martin Sherwin. (Credit: Men’s Health)

As a director Christopher Nolan likes to use the time-skipping, stream of consciousness style, in ‘Oppenheimer’ we are actually present at the Atomic Energy Commission’s review of Oppenheimer’s security clearance in 1954 and that hearing is then used as a setting for a series of flashbacks into portions of Oppenheimer’s life.

Stream of Consciousness may be the way our brains actually work but it is a very difficult writing, or film making style on both the author and audience. (Credit: ProwritingAid)

Beginning with a tour of Europe by the new doctor of Physics Oppenheimer meets other important physicists like Niels Bohr and Werner Heisenberg while learning about the new physics being developed in the 1920s. It’s also during this time that Oppenheimer becomes acquainted with American Physicist I. I. Rabi (played by David Krumholtz) who became a great friend of Oppenheimer but who rarely gets mentioned in stories about the Manhattan Project for reasons I will discuss in a little while.

A leader in the post WW2 generation of physicists I. I. Rabi received the Nobel Prize for his description of Nuclear Magnetic Resonance making possible the modern MRI. (Credit: Wikipedia)

After learning the secrets of Quantum Mechanics in Europe Oppenheimer returns to the US where he joined the faculty of UC Berkeley and became the theoretical counterpoint to experimentalist Ernst Lawrence (played by Josh Hartnett). The gentle antagonism between these two was actually one of my favourite parts of the movie.

Ernest Lawrence and his cyclotron, the first in a long series of ‘atom smashers’ leading to today’s Large Hadron Collider (LHC) at CERN. (Credit: Facebook)

While at Berkeley Oppenheimer also becomes involved with left-wing politics, his brother, his wife (played by Emily Blunt) and several close friends were all one-time members of the communist party although Oppenheimer himself never joined. These associations would later prove to be Oppenheimer’s downfall.

Fueled by the depression during the 1930s the Communist Party of America attracted many followers including many in academia. (Credit: Marxists Internet Archive)

The central portion of ‘Oppenheimer’ is of course his years as the scientific director of the Manhattan Project and leading scientist at Los Alamos labouratory. Oppenheimer was chosen for the position over several Nobel laureates by General Leslie Groves (Played by Matt Damon) for reasons that are still a bit murky, Groves just seemed to trust Oppenheimer more than the other, more prestigious physicists. Unlike the other versions of this story in ‘Oppenheimer’ Enrico Fermi and the other scientists at the University of Chicago have minor roles simply because they rarely interacted with Oppenheimer.

Constructed beneath the handball courts at the University of Chicago the first nuclear reactor was a critical step in the Manhattan Project but since Oppenheimer had little to do with the reactor it only appears for one brief scene in the movie. (Credit: Smithsonian Magazine)

Although I knew very well many of the details of the development of the A-bomb director Nolan still managed to make this portion of the movie engrossing and at times thrilling. Even though many filmgoers would be unfamiliar with nuclear physics and might be confused by such terms as isotopes, implosion and critical mass Nolan refused to turn his movie into a science lecture. ‘Oppenheimer’ is about the people who believed they were doing the right thing by building the most powerful weapon ever rather than the actual science of building a bomb. All the scientists at that time believed that the Nazi were also working on a bomb and were certain that with such men as Heisenberg the Germans had a 12-18 month head start.

Werner Heisenberg (r) led the German atomic bomb but because Hitler (l) considered modern physics to be ‘Jewish Science’ the German program never got much support and at the end of the war Heisenberg had barely started building a reactor. (Credit: First Curiosity)

After the war, and after Hiroshima and Nagasaki, many of those who worked on the Manhattan Project hoped to find some way to prevent an arms race, to stop the proliferation of nuclear weapons, to ‘put the nuclear genie back in the bottle’. In particular Oppenheimer’s opposition to the development of the even more powerful Hydrogen Bomb made him a number of enemies among the anti-communist politicians of the early 1950s. One in particular was Lewis Strauss (Played by Robert Downey Jr.) head of the Atomic Energy Commission. It was Strauss who orchestrated the hearings on Oppenheimer’s security clearance, using Oppenheimer’s known associations with communist party members back in the 1930s to question his loyalty. Many people today believe that it was the rescinding of his clearance that broke Oppenheimer, he stayed well out of the public eye for the rest of his life, but perhaps it was simply the final straw.

Security’s twin gods of ‘Clearance’ and ‘Need to Know’ are recurring themes in ‘Oppenheimer’. Who gets clearance and who doesn’t is often a matter of politics as much as loyalty to America. (Credit: Advantis Global)

My one complaint about ‘Oppenheimer’ deals with the portrayal of physicist I. I. Rabi. As I mentioned above Rabi is rarely mentioned in other stories about the first atomic bomb because despite his friendship with Oppenheimer he refused to join the Manhattan Project. In ‘Oppenheimer’ however Rabi plays a large role and the movie actually includes the scene where Rabi turns down Oppenheimer’s request to work on the project. In fact the movie seems to imply that Rabi was a pacifist who did not contribute to America’s war effort.

The Manhattan Project was not the United States’ only top secret program during WW2. The Radiation Lab at MIT produced a large number of radar systems that not only detected enemy aircraft but submarines along with radar trackers for naval guns and anti-aircraft weapons. (Credit: Google Arts and Culture)

Nothing could be further from the truth. Rabi was a central figure at MIT’s Radiation Labouratory developing the radar systems that gave the allies a tremendous advantage over the axis powers. After the war Rabi was known to say, “The Atomic Bomb may have ended the War, but Radar won it!” 

Still the atomic bombings of Hiroshima and Nagasaki did end the war and for good or ill started the nuclear age. (Credit: The Conversation)
Prometheus Bound by Peter Rubens. The Greeks understood how we often punish those who try to help us! (Credit: Wikipedia)

As a film ‘Oppenheimer’ is a great achievement, a thought provoking view on one of the most important moments in history and the man at the center of it. The acting is simply superb, the effects outstanding, the direction taught and engrossing. ‘Oppenheimer’ is just one of the best movies to come along in a long time so go see it. In Greek mythology Prometheus stole fire from heaven and brought it to men. For that the Gods chained him to a rock and tortured him for eternity. Oppenheimer’s greatest achievement, along with how he was treated afterwards, mirrors the Prometheus story in many ways.

 

Paleontology News for July 2023: Recent study highlights molecular evidence for the existence of Eukaryotic life forms as long ago as 1.6 billion years.

In these blog posts I have often mentioned that most of what we know about ancient life forms comes from examining the fossilized ‘hard parts’, the bones and shells of those creatures. Plants and animals without such hard parts, like jellyfish, slugs or many kinds of worms leave few traces in the fossil record and only a few fossil sites, like the famous Burgess Shale, give us a window into the soft bodied life forms of the past.

Nearly all fossils are the remains of the ‘Hard Parts’ of ancient animals, the soft flesh is rarely preserved. (Credit: FiveThirtyEight)
Fossils of animals without any hard parts, like this jellyfish, are extremely rare and hence extremely valuable to paleontologists. (Credit: The University of Kansas)

Even rarer is fossil evidence for single celled organisms like amoebas, algae or bacteria. Because of that we have little to no evidence to illustrate most of the evolution of life here on Earth. Seriously, most researchers think that the first life forms on our planet originated more than 3.5 billion years ago.  Multi-cellular creatures however only appeared about 650 million years ago so for the first 3 billion years or so Earth was inhabited only by single celled organisms. Our understanding of how single celled life evolved from mere bags of organic material to cells complex enough to develop into multi-cellular creatures is mostly theories with only bits of evidence to back them up.

For most of the history of Earth living things were single celled creatures like this Amoeba. Creatures that left little fossil evidence leaving us with a lot of theories of how early life evolved but few facts. (Credit: KLive Science)

One problem in particular is time lapse between when our theories say that the first eukaryotic cells should have evolved, some 1.6 billion years ago, and the first unmistakable signs of their existence some 800 years later. Now, what is a eukaryotic cell and why is the timing of their development so important? Let me take a minute or two to explain.

Prokaryotes, like this bacteria, have little internal structure. The various parts of their metabolism, including their DNA, just kind of float in their cytoplasm. (Credit: Javatpoint)

As I said above the first living things here on earth were probably little more than bags of organic compounds, some RNA, maybe DNA, proteins for structure with fats and carbohydrates for energy. There was little or no structure inside the bag as the different types of compounds just mixed together. Modern bacteria and blue-green algae are still very much like this and as a group such ‘primitive’ cells are called prokaryotes from the Greek words ‘pro’ meaning before and ‘karyon’ meaning kernel, the kernel in this case being a cell nucleus where a cell’s genetic material is kept safe. So a prokaryote is a single celled creature without a nucleus.

Eukaryotes, like an amoeba or every cell in your body, have a much more complicated internal structure with many ‘organelles’ like the mitochondria, or Golgi Bodies or the Nucleus itself where the cells DNA is kept protected. (Credit: News Medical)

Cells with a nucleus are referred to as eukaryotes, cells with a kernel. Such cells include single celled creatures like amoeba and paramecium but also all of the cells of all multi-cellular organisms, plants or animals including all of the cells of your body. In addition to a nucleus eukaryotic cells usually also possess other structures as well like mitochondria, ribosomes and my personal favourite the endoplasmic reticulum. Obviously the evolution of eukaryotes from prokaryotes was an important moment in the history of life and so an 800 million year gap in when we think they should have evolved and when we have good evidence that they did evolve is a big problem.

Simplified view of how the evolution of eukaryotes from prokaryotes began. Problem is that this process is very difficult to confirm in the fossil record. (Credit: Understanding Evolution)

Now single celled organisms, whether they be bacteria or amoeba rarely fossilize. So instead of looking for the actual remains of eukaryotes in ancient rocks paleochemists look for chemical traces, that is traces of complex chemicals that are produced by eukatyotes but not by prokaryotes. The chemicals that paleochemists were looking for are the familiar group known as steroids, especially the steroid cholesterol. These chemicals are very useful for living cells because of their ability to allow cells to survive in a wider range of temperatures, repeated de-hydration and re-hydration as well as enduring high levels of ultraviolet light.

Cholesterol is one of a class of chemicals known as Steroids. Despite their bad press Steroids, including Cholesterol are very important to the functioning of our metabolism. (Credit: Saylordotorg.github.io)

Producing steroids however requires a lot of oxygen and a billion years ago the Earth’s atmosphere had very little of the gas. That led the researchers to propose a new theory, that between 1.6 and 800 million years ago an intermediate form of eukaryotic-like organisms dominated the Earth. These intermediate eukaryotic-like cells could not produce full steroids, or crown steroids as they are known but only simpler protosteroids and hence the intermediate cell forms are known collectively as the ‘Protosterol biota’.

Artist’s concept of what the ‘Protosterol Biota’ could have looked like. Something like the more advanced Eukaryotes these single celled creatures were unable to produce complex chemicals like steroids. (Credit: Sci.news)

With this new idea in mind paleochemists went searching for protosteroids in rocks of the right age and quickly hit the jackpot, they found protosteroids almost everywhere they looked. It is now thought that, during the time when the protosterol biota were dominant the true eukaryotes evolved in those harsh environments where crown steroids were needed in order to survive, perhaps on the land the researchers speculate. Then, about 800 million years ago, when the oxygen levels in the atmosphere increased to near present levels the true eukaryotes took over and the protosterol biota became extinct.

Paleochemist Jochen Brocks examines 1.6 billion year old rocks containing the chemical traces of the protosterol biota. (Credit: Reuters)

The evolution of complex eukaryotic cells from their prokaryotic ancestors was one of the most important advances in the history of life, setting the stage for the evolution of multicellular creatures. It is only reasonable therefore that the process should have taken place in stages. The protosterol biota seems to have been that intermediate step on the road to life as we know it today.

Movie Review: Indiana Jones and the Dial of Destiny

As I’m sure everyone knows, Indiana Jones and the Dial of Destiny is the fifth and latest movie adventure of the archaeologist character Indiana Jones who first appeared in ‘Raiders of the Lost Ark’ way back in 1981. It is also the last adventure according to its 81-year-old star Harrison Ford, which means that everyone concerned with making the movie had an extra incentive to try to go out on a high note.

The first and still the best. Raiders of the Lost Ark set a standard for action movies that has never been surpassed. (Credit: Fathom Events)

To let you all know, I’m a big Indiana Jones fan, I consider ‘Raiders of the Lost Ark’ to be the best action movie ever made. I also really liked both the second and third Indiana Jones movies, ‘Indiana Jones and the Temple of Doom’ and ‘Indiana Jones and the Last Crusade’. At the same time I really didn’t like the forth movie, ‘Indiana Jones and the Crystal Skulls’ known to my friends and I as ‘Indiana Jones and the Movie that should never have been Made’. Those facts should give you some idea of just how honest my opinion about ‘Dial of Destiny’ will be.

Every Indiana Jones movie actually contains two stories, before going after the ark of the Covenant in Egypt Indy first spent half an hour searching in South American to find a golden idol. (Credit: Empire Online)

‘Dial of Destiny’ begins in the last days of World War 2 with Indy and another archaeologist, Basil Shaw played by actor Toby Jones, trying to prevent the Nazis from stealing various historical artifacts, one in particular being the head of the spear that pierced Jesus as he hung from the cross. That artifact turns out to be a fake but at the same time Basil recognizes another as the Antikythera, a mysterious clockwork like mechanism that was found in a shipwreck at the bottom of the Mediterranean in 1901 and is dated to sometime before about 80BCE. Of course Indiana Jones succeeds in defeating the Nazis and rescuing the Antikythera.

Indiana Jones seems to be at his best when he’s up against the Nazis. Three of the five movies have everybody’s favourite bad guys as the villains. (Credit: IMDb)

   One of the most interesting aspects of ‘Dial of Destiny’ occurs during this opening segment for while Indiana Jones was still fairly young during WW2 actor Harrison Ford who plays him is now 81. So while Ford did the acting the producers employed an Artificial Intelligence (AI) imaging program to make his face look young, using Ford’s previous outings as Indiana Jones as a guide. The effect works surprisingly well, Harrison Ford looks young in this opening segment and in some ways that’s a bit terrifying. Think about it, what does the future hold, will we see Humphrey Bogart staring in the next ‘Star Wars’ installment, will the entire original crew of ‘Star Trek’ be brought back from the dead to act in new episodes written by an AI generated version of D.C. Fontana? (Yea, I know a couple of them are still alive but they’re old!!!!). In fact the use of AI in films is one of the big issues that led to the current strike by the actor’s union!

Harrison Ford was 81 years old when he filmed this scene. He doesn’t look it thanks to AI! (Credit: Slash Film)

 After defeating the Nazis in the opening the story skips ahead about 25 years to 1969. Here Professor Henry Jones, to use Indy’s real name, is a retiring teacher at a New York City University and obviously none to happy about that fact. In fact Indiana’s life is a bit of a mess, his son has died, apparently in Vietnam and his wife Marion, played by Karen Allen in both the first and fourth movies, is divorcing him. Here the 81-year-old Ford does some poignant acting showing the misery of someone who has all the time in the world on their hands but who really doesn’t think they have much of a future ahead of them.

In a later scene we see the real Harrison Ford sans AI. Dial of Destiny does give Indy the chance to grow old while still displaying the heroics that we’ve all come to expect. (Credit: Syracuse.com)

Indiana’s retirement doesn’t last long however for Basil’s daughter Helena, played by actress Phoebe Waller-Bridge, shows up with the idea of finding the other half of the Antikythera and putting the two together. Before Indy can crack his whip he’s off on another daring adventure, fighting Nazis who want to refight WW2 and unearthing ancient secrets. I’ll stop my description at this point so as not to give away too many spoilers.

The three main pieces of the Antikythera mechanism. The use of gears in the ancient work was a shock when the mechanism was brought up from a shipwreck off the Greek island of Antikythera. (Credit: Encyclopedia Britannica)

I would like to take a minute or two to discuss the actual Antikythera however, for there really is a mysterious mechanism that was brought up from a Greco-Roman shipwreck back in 1901. In the movie the Antikythera is in perfect working order, ready to do whatever it was made to do. In reality however two thousand years on the seafloor has left the artifact so corroded that it is never going to work again. As to why the Antikythera is such a mysterious object, simply put, it’s a gearbox, the sort of mechanism that you’ll find in an old watch or the transmission of your car. Most archaeologists agree that the Antikythera is a kind of clock designed to follow the motion of the Sun and Moon across the sky.

What we think the Antikythera mechanism originally looked like. The device was probably used as both a calendar and for keeping track of where celestial objects where in the sky. (Credit: Nature)

Prior to the discovery of the Antikythera historians didn’t think such gear based technology had been invented until about the 14th century yet the Antikythera is at least 1500 years older. Also, in the movie it is simply accepted that the Antikythera was made by the ancient Greek mathematician Archimedes. Well, aside from the time being about right there is no evidence at all to link the Antikythera to Archimedes.

Archimedes of Syracuse was one of the giants of the ancient world. (Credit: Slideshare)
But what he is best known for today is taking a bath! Eureka! (Credit: Englesberg Ideas)

So, is ‘Indiana Jones and the Dial of Destiny’ a good movie? Is it a worthy final chapter to the Indiana Joes saga? I think so, the movie manages to maintain a roller coaster pace of thrills and chills even while allowing Harrison Ford to play a guy who’s getting too old for this shit. The movie is a bit of a nostalgia trip, I wouldn’t recommend it as a first Indiana Jones movie to see. Nevertheless ‘Indiana Jones’ is a fun two and a half hours with a character we’ve all grown to love. All in all ‘Dial of Destiny’ is a good way to say goodbye to Indiana Jones.   

Archaeology News for June 2023: Two ancient burial sites that teach us a lot about both the material wealth and cultural practices of their societies.

Everybody knows that much of archaeology is carried out in ancient burial sites, graveyards, tombs and etc. Part of the reason for this is that we humans have always had a tendency to try to take some of our Earthly possessions with us when we pass on to the world to come. The treasures found in the tomb of King Tutankhamun are the most famous examples of this but there are countless others. We’ve learned much about the technology of ancient societies by unearthing and examining the grave goods left behind by those people.

The tomb of Tutankhamun is probably the most famous archaeological site ever found. (Credit: BBC)

At the same time studying those olden gravesites can also reveal a great deal about the customs and rituals, the religious and ethical behaviour of the people who were buried there. In this post I will be discussing some recent discoveries made at two such burial sites, two locations not greatly separated in either space or time but which display considerable differences in terms of social changes.

Ritual behavior, such as receiving first communion, doesn’t leave any artifacts for archaeologists to discover later. (Credit: Our Sunday Visitor)
Unless that is an artifact illustrating the ritual is deliberately created. (Credit: Diocese of Lansing)

The first site comes from an area near the German city of Munich where an excavation team searching for unexploded munitions left over from World War II happened upon two burials. Professional archaeologists were quickly called in and the entire site carefully exhumed. Perhaps the most interesting find was a sword that had been deliberately rendered useless by heating it in the middle of the blade and then folding it over. Other weapons found included a spearhead and a portion of a shield.

Unexploded munitions left buried in the ground from WW1 and WW2 are a real danger, several people are killed by them every year. (Credit: NDTV.com)

Some of the other grave goods found included a pair of scissors so well preserved that the archaeologists were tempted to use them along with a fibula or clasp and a chain belt. Based upon the items found the researchers think that the occupants of the graves were a man and a woman but they can’t be certain because these were cremation burials where the deceased were burned to ashes and the ashes then buried in a ceramic pot.

Scissors, a razor and folded sword are among the items discovered in the gravesite outside Munich. (Credit: Archaeology)

And that gives a clue as to what society these two people came from because the last culture in this part of Germany to practice cremation were the Celts, that’s pronounced ‘Kelts’ not ‘Selts’ by the way.  The Celts were an Iron-Age, Indo-European people who spread across northern Europe from present day Turkey to Ireland and who fought both the Greeks and Romans for over 500 years. The grave goods found were also typical of the Celts; in fact not only was the sword definitely Celtic in design but the way in which it was folded has also been seen in other Celtic graves sites. The site has been dated to around 200-300 BCE and the grave goods sent to the Bavarian State Office for the Preservation of Monuments where they will be cleaned, preserved and studied.

The Romans practiced both inhumation and cremation of their dead. Here is an illustration of the cremation of the Emperor Augustus. (Credit: ThoughtCo)
Grave items from a Celtic burial in the Balkans, the ashes of the deceased were placed in the urn center top. Notice again the bent sword like the one discovered at the site outside Munich. (Credit: Balkan Celts – Word Press)

At the same time that the inhabitants of the graves in Germany lived other Celts were living in the British Islands and one of the biggest questions in archaeology today is just how different were the Celts in today’s Germany from those in today’s Britain. The fates of those groups were certainly very different however for in 43CE the Roman Emperor Claudius invaded Britain and conquered the lands that would become England and Whales. In the 400 years of Roman rule that followed many of the Celts living in Britain would become Romanized. Indeed it has been suggested by some historians that the only real difference between the Celts and the later Germanic tribes that destroyed the Roman Empire is that the Romans conquered the Celts but not the Germans.

Caractus, the leader of the Celtic Britains against the Romans is brought before the Emperor Claudius in Rome. (Credit: Historic UK)

Our second burial site comes from the late Roman period in Britain where more than 60 graves were found outside the town of Garforth near Leeds. The site must have been in use as a cemetery for a considerable length of time because it not only included late Roman burials but early Anglo-Saxon ones as well. The way the archaeologists could distinguish the two groups was that the graves of the Romanized Britains were oriented east-west in the Christian fashion while the Anglo-Saxons burials were aligned north-south. Of course carbon-14 dating also helped, yielding a time frame of 400-600 CE for the burials.

Two of the graves excavated in Garford, England. (Credit: BBC)

The fact that the remains unearthed in Garforth were skeletons, not cremated ashes was one big difference with the burial outside Munich. Another was the scarcity of grave goods in the Roman-Christian graves as opposed to the Anglo-Saxon burials, which often contained objects such as knives and pottery. However the most interesting find did come from one of the Roman-Christian burials where the deceased, a woman had been laid to rest in an impressive lead coffin. All the other coffins must have been made of wood for they had all decayed back into the soil.

Lead coffin used at Garford cematary. This burial must have been that of a person of high estate since a coffin like this would have been very expensive. (Credit: The Telegraph)

The site at Garforth was discovered, as many archaeological sites are in the UK, during the survey of the area for a possible housing development. The finds unearthed at Garforth, including the lead coffin are in the care of the West Yorkshire Archaeological Advisory Service, which will continue their analysis with the intent that some of the finds will one day be displayed at the Leeds City Museum.

Leeds City Museum in England. In the UK many cities and large towns have their own local museums where you can learn a lot about the local history and natural history. (Credit: Cool Places)

Many of our most important cultural practices and rituals involve how we as a society treat our dead. Because of that fact archaeologists can learn a lot about not only an ancient people’s technology but their beliefs as well by studying grave sites. 

Astronomy News for May 2023: First ever observations of a dying star swallowing one of its own planets in a preview of what astronomers think is Earth’s eventual fate.

Astronomers are fascinated by variable stars, stars that can change their brightness whether it be over a timescale of months or days or in some cases as little as seconds. After all you’d think that an object that has a lifespan of millions if not billions of years shouldn’t change much over a single human lifetime, but many do. Some stars, like the Cepheid variables or eclipsing variables vary in a regular pattern and we can learn a great deal about the stars by observing that pattern. Other stars, like nova or supernova literally explode in a tremendous flash making them especially interesting to astronomers.

Brightness curve for a typical Cepheid variable star. By measured the time from peak brightness to peak brightness astronomers can determine the actual amount of energy the star produces. That allows them to calculate the distance to that star. (Credit: Physics Libre Texts)

The Zwicky Transient Facility (ZTF) is a program run by Caltech University that uses the Samuel Oschin Telescope on Mount Palomar Observatory to scan the sky every night looking for any star that suddenly changes its brightness. Back in 2020 ZTF observed a dramatic increase in the brightness of a star that was designated as ZTF SLRN-2020, and which lies about 12,000 light years away in our own Milky Way. Over a ten day period the star had brightened over 100 times its normal brightness and remained brighter for 100 days before returning to normal.

With a mirror 48 inches in diameter the Samuel Oschin telescope is used to study variable stars. (Credit: The Planetary Society)

At that time Kishalay De was a graduate student working on his Ph.D. and was given the task of trying to understand what had happened to ZTF SLRN-2020. Doing a little checking De found that ZTF SLRN-2020 was a Sun-like star that was entering old age, meaning the star had used up its original hydrogen fuel and had begun to burn helium. When that happens to a star its core has to greatly increase in temperature and this causes its outermost layers to puff up, in astronomical terminology the star has passed from its main sequence to its red giant phase. De quickly determined that ZTF SLRN-2020 was not a repeating variable, nor was the increase in brightness great enough to be a nova or supernova explosion. Unable to figure it out, and very busy trying to finish his doctoral thesis De put the data on ZTF SLRN-2020 aside. It was only last year that now Dr. Kishalay De of MIT managed to get back to thinking about ZTF SLRN-2020.

Astronomer Kishalay De of MIT talking about his discovery of a star swallowing one of it’s planets. (Credit: Harvard Gazette, Harvard University)

The first thing Dr. De decided to do was to get more data about ZTF SLRN-2020 from other instruments at other wavelengths. One instrument in particular was NASA’s NEOWISE satellite that orbits the Earth scanning the sky in the infrared. Turned out that NEOWISE, which stands for Near Earth Object Wide field Infrared Survey Explorer, had in fact observed an increase in the brightness of ZTF SLRN-2020 fully nine months before ZTF had observed it in the visible wavelengths. More than that in the infrared ZTF SLRN-2020 was still slightly brighter than normal, two full years later. Such an increase in the infrared brightness indicates that something very close to the star is generating a huge amount of dust so that as the dust warms up it emits infrared.

Designed to search for asteroids and comets the NEOWISE Satellite can also be used to study variable stars. (Credit: Wikipedia)

Based on the data from both ZTF and NEOWISE Dr. De thinks he has the answer. As it grew larger in size ZTF SLRN-2020 has swallowed one of its planets, a planet about the size of Jupiter. According to Dr. De what happened to ZTF SLRN-2020 was this, as the outer surface of the star grew close to the planet the planet’s gravity pulled some of the star’s material away into space where it cooled becoming the dust that caused the initial increase in infrared brightness seen by NEOWISE. As the star continued to grow however it finally swallowed the planet itself causing the increase in brightness at optical wavelengths seen by ZTF. After swallowing the planet however there is still enough dust orbiting around the star to cause it to continue to glow in the infrared.

As stars run out of their hydrogen fuel they begin to burn helium. This causes their cores top become much hotter which in turn causes their outer surfaces to expand making the star hundreds if not thousands of times bigger. (Credit: Earth Sky)

If Dr. De’s analysis is correct then astronomers have observed for the first time something that they think must happen rather often in the Universe. After all, nearly every star will someday enter a red giant phase and if most stars have planets then a lot of planets must end up getting swallowed by their parent star.

In the long history of the Universe this must be a fairly common occurrence, a star swallowing one of its planets. (Credit: Physics – APS.org)

In fact that is quite possibly the eventual fate of our own planet Earth, don’t worry it won’t happen for about another five billion years or so. Still, like all stars someday the Sun will start to run out of its hydrogen fuel and as it starts to burn helium it will puff up to become a red giant just like ZTF SLRN-2020 is doing now. Based upon our observations of other stars with approximately the same mass as the Sun, including ZTF SLRN-2020, then the Sun will undoubtedly swallow first Mercury and then Venus. Whether or not the Earth gets swallowed or simply burnt to a crisp by a much larger, and hence much closer Sun is debatable, but in either case the conditions here on our planet will make life impossible.

Whether the Earth eventually gets swallowed or not, the Sun’s surface will come so close that our planet will be reduced to a burnt cinder. (Credit: EarthSky)

So is what happened to ZTF SLRN-2020 a preview of what’s going to happen someday here in our solar system. Only time will tell, and we all know that the Universe has plenty of that.