Today’s news is a hot mess – literally. We bring you stories of our galaxy flaring out jets, the formation of the universe’s web of large scale structure, and of a binary star system forming in a pretzel of gas and dust.
This is the Daily Space for today, Monday, October 7, 2019. I am your host, Dr Pamela Gay, and I am here to put science in your brain.
Most Mondays through Fridays, either I or my cohost Annie Wilson will be here bringing you a quick rundown of all that is new in space and astronomy.
Today starts with explosive news about the history of our galaxy. In recent years we’ve been finding a steady stream of evidence that our Milky Way has gone through periods of wild activity, during which high energy events in the heart of our Galaxy cleared out bubbles of material we see today. That bubble-blowing behavior was nothing compared to the outburst described in a new article coming out in the Astrophysical Journal. Scientists led by Professor Joss Bland-Hawthorn have determined that roughly 3 million years ago, an explosive event near our galaxy’s supermassive black hole blasted out not just a bubble but an entire cone of space that burst out forming temporary jets. This kind of activity is called a Seyfert flare, and isn’t something we really every imagined our galaxy having, especially not this recently in its history.
3 million years ago, our planet’s dinosaurs had already come and gone, and the earliest ancestors of man were starting to walk the savannah of Africa. This blast of energy could have lasted for 300,000 years, which for a galaxy is no time at all, but was long enough to blast energy out to a distance of 200,000 light years.
It’s impossible to know exactly what caused this outburst. The most likely culprit is something getting compressed by the extreme gravity near Sag A*, our Galaxy’s supermassive black hole. That may not be the only answer, and exactly what may have been destroyed is unknown.
There are two really interesting possibilities raised by this research: either the galactic activity we see as we look around the universe may be much more common than previously thought, and even often more transitory than we thought, Or – it could just be that our galaxy is a weirdo system, and that would be awesome too.
Our galaxy is just one of countless billions that trace out the large scale structure of the universe. Until recently, our understanding of the details was limited to what we could model in computers. These models replicated the bright clusters we can see see while guessing at the fine details. To see those details would require the largest telescopes in the world looking for hour after hour at the same region of sky trying to collect enough light to see faint galaxies. In a new paper in the journal Science, researchers describe how they used the Very Large Telescope in Chile to make these observations and see this structure for the first time. According to the press release they “studied a region of the sky that contains a proto-cluster of galaxies – a region where a large cohort of galaxies is beginning to assemble. Galaxies within the cluster emit ultraviolet light, a result of new stars forming inside or of churning regions around supermassive black holes at the galaxies’ centers.” The filaments seen in these images stretch for millions of miles. And in one of those moments of, all is as it should be – they also look like we had expected.
From galactic-scale science, we next turn to a story of binary star formation in which the forming stars have gravitationally swept the surrounding gas and dust into the shape of a pretzel. In new images taken by the Atacama Large Millimeter Array, astronomers have been studying the youngest forming stars in the Benard 59 dark nebula. This remarkably complex system includes an outer dust disk that surrounds both stars, and each star also has its own disk that appears to be about the size of our solar system’s asteroid belt. These disks have complex structures that channel material from the large outer disk, in toward each individual star. The complexity comes from a variety of factors, including the motions of these two stars as the orbit around each other and the motions of the disks while they orbit around the stars. With this structure, seeing is believing and it also really helps with understanding. We have an image on our website, dailyspace.org, that you can see for yourself.
And that rounds out our show for today.
Thank you all for listening. The Daily Space is produced by Susie Murph, and is a product of the Planetary Science Institute, a 501(c)3 non profit dedicated to exploring our Solar System and beyond. We are made possible through the generous contributions of people like you. If you would like to learn more, please check us out on patreon.com/cosmoquestx
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