Tag: Betelgeuse

Canadian Naturalists follow the spread of a new song in the White Throated Sparrow. Is this an example of a change in the cultural of a species of bird?

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. 

The red super giant star Betelgeuse in the constellation Orion has lost half its brilliance. Could that mean it is about to explode as a Supernova?

One of the most familiar stars in the night sky is Betelgeuse, the star that marks the right shoulder of Orion the hunter. (Right shoulder, that means we see it on the hunter’s left!). Generally Betelgeuse is the eleventh brightest star in the sky but because there are several other very bright stars nearby Betelgeuse is very easy to find. Not only is Rigel, Orion’s left foot, slightly brighter but to Betelgeuse’s upper right is Aldebaran the eye of Taurus the Bull while to the lower left is the brightest of all true stars Sirius. I my opinion these stars together make Orion and the region around it one of the most interesting parts of the night sky, and the simplest to find.

The Constellation of Orion the Hunter. Betelgeuse is Orion’s Shoulder and is a red star. (Credit: EarthSky)

Lately however Betelgeuse has not been looking as strong and bright as usual. Astronomers have known for centuries that Betelgeuse varies in its intensity by as much as a factor of two but for the past month the star’s energy output has been the lowest it’s been for over a hundred years.

A red giant star, Betelgeuse is so large that if it replaced our Sun it would swallow all of the planets out to Jupiter. (Credit:WWW.Severe-Weather.eu)

So what’s happening to Betelgeuse? Could its recent convulsions be a prelude to something extraordinary, perhaps even the star’s soon exploding as a supernova?

Betelgeuse often goes into convulsions but its recent activity is abnormal. (Credit: Discover Magazine)

It’s worth considering; our current theories about Type 2 supernovas tell us that Betelgeuse is a prime candidate. Only very heavy stars that have used up all of their nuclear fuel end their lives as type 2 supernovas. At an estimated mass of twelve times that of our own Sun and with a bloated red sphere as large as the orbit of Jupiter indicating that both its hydrogen and helium resources are gone Betelgeuse seems to be ready to go at any time.

A Supernova explosion is so powerful that for a couple of weeks it can outshine all of the stars in its galaxy combined! (Credit: Harvard Gazette – Harvard University)

Of course at any time for an object as long lived as a star could mean sometime in the next million years or more. However a recent paper has suggested that Betelgeuse’s end might come any time in the next 100,000 years so there is a slight chance it could be happening soon.

So what would Betelgeuse going supernova mean to us here on Earth? Would there be any danger? Well at an estimated distance of 700 light years Betelgeuse is too far away for its burst of radiation, mostly gamma and X-rays, to do any damage to our atmosphere. However since the total amount of light coming from Betelgeuse could be as much as that of a full Moon, all squeezed into a single point of light in the sky, that point would be intensely bright, easily seen in daytime. It is possible that anyone staring at that point for too long could suffer some eye damage. Still, all in all there’s no reason to get too excited, but a nearby supernova would be something to see.

The Crab Nebula is the remnant of a Supernova that was seen in the year 1054. (Credit: YouTube)

Especially for astronomers, over the last century there have been hundreds of observations of supernova in other galaxies but those are so far away that precise measurements of what is happening are difficult to make. Even worse, when a star goes supernova in another galaxy astronomers almost never have any observations of the star before it went nova.

Only once, back in 1987 when a star in the Large Magellanic Cloud, a satellite galaxy to our Milky Way, went supernova have astronomers had any observations of a star before it exploded. The last star to go supernova in our own Milky Way galaxy was way back 1604 when telescopes were nothing more than cardboard tubes with a lens at each end. If Betelgeuse or another nearby, well-known star were to explode it would allow astronomers to test many of their theories about supernovas and star evolution in general.

A Hubble space telescope image of the Supernova 1987a as seen today. The rings are a part of the expanding shell of the explosion. (Credit: SolStation.com)

Personally I’ve been hoping to see a naked eye supernova most of my life so I’ll be keeping my fingers crossed the next few months. You know, writing this post about the possibility of Betelgeuse going supernova has made me realize that I ought to write a post just about supernova. After all type 1 supernova are an entirely different kind of animal from type 2 so I ought to describe them. Maybe I’ll do so here in the next few months, so keep coming back.