Podcaster: Dr. Pamela Gay;
Title: Escape Velocity Space News – EVSN: Cool Worlds, Exploding Stars, & an Asteroid That Missed Earth
Organization: Cosmoquest
Link: http://dailyspace.org/
Description: From August 20, 2020
Join us today as we look at how citizen science helped discover 100 cool worlds nearby. Then we examine evidence that exploding stars may have contributed to a mass extinction on Earth. Speaking of mass extinctions, an asteroid narrowly missed our planet last weekend.
Bio: Dr. Pamela Gay is a Senior Scientist at Planetary Science Institute and a Director of CosmoQuest.
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Transcript:
This is the daily space for today Thursday August 20th 2020 I am your host Beth Johnson, and I’m here to put planetary science in your brain To understand our place in the universe we have to understand the universe That’s a tall task though, and one I’m not generally equipped to cover I prefer to stay closer to home, and I particularly love planets Today’s news is all about planets and this first story is literally and figuratively cool a New paper in the astrophysical journal details the discovery of almost a hundred cool worlds known as brown dwarfs Which were found with the help of a huge group of citizen scientists Brown dwarfs are sometimes referred to as failed stars because they are between the most massive planets and the smallest stars in mass They don’t have enough mass to sustain nuclear reactions as a result They are cold and dim which also makes them very difficult to find in fact We only have success finding them in the relatively close vicinity of our Sun the backyard worlds project found nearly 1,500 new brown dwarfs and these hundred included in the paper are the coolest of the bunch with temperatures approaching that of Earth The data for this project was collected from a variety of programs run by the National Science Foundation’s National Optical Infrared Astronomy Research Laboratory or NOIR Lab and then made available to some 100,000 volunteers through the backyard worlds project Those volunteers carefully scoured the images for moving pixels and identified changes in the image and several observatories Including NASA’s Spitzer Space Telescope did follow-up observations to gather the temperature estimates The discovery of these very cool planets helps bridge a gap in the low temperature range of brown dwarfs according to lead author Aaron Meisner These cool worlds offer the opportunity for new insights into the formation and atmospheres of planets beyond the solar system This collection of cool brown dwarfs also allows us to accurately estimate the number of free-floating worlds roaming interstellar space near the Sun co-author Jackie Faraday explained This paper is evidence that the solar neighborhood is still uncharted territory and citizen scientists are excellent astronomical cartographers Mapping the coldest brown dwarfs down to the lowest masses gives us key insights into the low mass star formation Process while providing a target list for detailed studies of the atmospheres of Jupiter analogs My favorite part of this story is that it keeps referencing the nearness of the objects to our own Sun When in fact the closest one is 23 light-years away and most are 30 to 60 light-years away neighborhood indeed Hmm While these brown dwarfs may not be as close as the headlines imply That doesn’t mean that distant bodies cannot affect us here on Earth a new paper in the proceedings of the National Academy of Sciences Theorizes that cosmic rays from supernova may be responsible for at least one mass extinction event The event in question occurred between the Devonian and Carboniferous periods around 359 million years ago Rocks dated to this time contain numerous plant spores that show evidence of long-lasting ozone depletion while more terrestrial events could lead to that type of ozone catastrophe the evidence for those is Inconclusive at best the researchers proposed that a supernova or possibly more than one from about 65 million light-years away is the real culprit according to the article a Supernova delivers a one-two punch the explosion immediately bathes Earth with damaging UV x-rays and gamma rays Later the blast of supernova debris slams into the solar system subjecting the planet to long-lived irradiation from cosmic rays Accelerated by the supernova the damage to Earth and its ozone layer can last for up to 100 years however fossil evidence indicates a 300,000 year decline in biodiversity leading up to the Devonian Carboniferous mass extinction Suggesting the possibility of multiple catastrophes, maybe even multiple supernova explosions To prove their theory the team hopes to find a couple radioactive isotopes Plutonium-244 and samarium-146 in the rocks and fossils of the time period Since these isotopes do not occur naturally on Earth.
They had to have come from space in a cosmic explosion Lead author Brian Fields Explains that these isotopes are like green bananas and here is my favorite quote today When you see green bananas in Illinois, you know, they are fresh and you know They did not grow here like bananas plutonium-244 and samarium-146 decay over time So if we find these radioisotopes on Earth today We know they are fresh and not from here the green bananas of the isotope world and thus the smoking guns of a nearby supernova We here at CosmoQuest wish the team luck in their search for these isotopes.
I’m Honestly pretty excited to see where this story goes Of course when we talk about extinction events everyone immediately thinks of dinosaurs and giant asteroids Which is why our next story has been a question on our show several times this week Over the weekend an asteroid formerly known as ZTF 0DQ-DXQ Was discovered by the Zwicky Transient Facility several other telescopes were able to do quick follow-up observations and confirmed to the size and trajectory of the asteroid Unfortunately, it was discovered after it already zipped by Earth Fortunately, it’s only about the size of an SUV. So it wouldn’t have caused any damage It came within 3,000 kilometers of Earth though making it the closest known asteroid to miss Earth Since the tiny visitor was confirmed by multiple observatories. It is now known as 2020 QG, which Let’s be honest isn’t much better of a name While we’re on the topic of asteroids We have one more tiny piece of news to share today the Hayabusa 2 spacecraft which visited asteroid Ryugu from June 2018 to November 2019 Is on its way home with samples.
The Japan Aerospace Exploration Agency received permission from the Australian government To land the sample capsule in the Woomera prohibited area in South Australia. The landing is scheduled for December 6 More samples y’all of an asteroid Japan has done this before and I am still impressed and excited. We’ll update later this year.
So stay tuned Finally on a more sober note, our thoughts are with everyone affected by the wildfires here in California I have been surrounded by smoke ash has been falling on the balcony and the roof and the cars And the air has been toxic. I have friends that have been evacuated from their homes Last night. I got emotional watching the death images of a fire camera in the Santa Cruz Mountains and then dr Pamela and I spent part of the night watching the fire encroach upon the observatory We are happy.
However to report the observatory survived the night There are unconfirmed reports that some residence buildings were destroyed a couple small domes suffered damage and the majority of the complex We’ll need a deep cleaning. Oh Good news indeed Thank you to Cal fire for working to preserve this important piece of our local history and our ongoing scientific endeavors I know that a lot of people are losing homes and struggling and our worry for a collection of domes and buildings Can seem crass by comparison? Feelings cannot be helped though The observatory is a huge part of the history of San Jose and there’s a ton of astronomy going on there to this day well Not this day, but up until the fire Lick has been an important part of my career short as it has been so far during my internship at SETI I went up for a tour with my undergraduate class and I took my mentor.
Dr Peter Yeniskens After the tour was over and I had gotten to look at Saturn through the big 36-inch telescope Peter and I worked on my research project the cameras for all sky meteor surveillance It’s a box of 24 security cameras that point up at the sky in a domed array and they photograph the sky all night We did some maintenance and upgrades while we were there and collected the hard drives I then had to go through the data and find meteors and meteor showers It was the best summer of my life to be honest I hope that we can soon update with good news about those cameras.
They were still collecting data last I heard 2020 has been rough y’all. I know that you know that I want to hug my friends in person I want to breathe freely without masks. I want to travel Since none of that can happen right now.
I’m glad to have all of you listeners Stay safe everyone, please That rounds out the news for today, this has been the Daily Space Today’s episode was written by me Beth Johnson Engineering is provided by Allie Pelfrey and web content is produced by me. The show is executive produced by dr Pamela Gay You can get a complete transcript show notes and see images related to each of our stories at our website daily space org We are production of the Planetary Science Institute a 501 c3 nonprofit Dedicated to exploring our solar system and beyond we are here Thanks to the generous contributions of people like you. The best way you can support us is through patreon.com Slash Cosmo quest X like us. Please review us your reviews wherever you listen to podcasts We’ll make it easier for others to find this show. Please help grow our community You never know whose life you can improve with a daily dose of science
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365 Days of Astronomy
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As we wrap up today’s episode, we are looking forward to unravel more stories from the Universe. With every new discovery from ground-based and space-based observatories, and each milestone in space exploration, we come closer to understanding the cosmos and our place within it.
Until next time let the stars guide your curiosity!