Podcaster: Richard Drumm
Title: Space Scoop: Could Aliens Be Closer Than We Thought?
Organization:365 Days Of Astronomy
Link : astrosphere.org ; http://unawe.org/kids/unawe1134/
Description: Space scoop, news for children
Bio: Richard Drumm is President of the Charlottesville Astronomical Society and President of 3D – Drumm Digital Design, a video production company with clients such as Kodak, Xerox and GlaxoSmithKline Pharmaceuticals. He was an observer with the UVa Parallax Program at McCormick Observatory in 1981 & 1982. He has found that his greatest passion in life is public outreach astronomy and he pursues it at every opportunity.
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Transcript:
This is 365 Days of Astronomy. Today we bring you a new episode in our Space Scoop series. This show is produced in collaboration with Universe Awareness, a program that strives to inspire every child with our wonderful cosmos.
Today’s story is:
Could Aliens Be Closer Than We Thought?
Um… Well, no. They aren’t.
Consider this:
When early explorers first set out from Europe headed west across the Atlantic Ocean, many people thought the world was flat. They worried that if you sailed far enough, you would drop off the Earth into nothing.
There were many others, however, who suspected the Earth was spherical and that sailing west could take you to the far EAST, avoiding the lengthy sail around Africa.
Today, not only has every corner of the Earth been thoroughly explored, we’ve also visited every other planet and a couple dwarf planets in our Solar System. These, too, are voyages of discovery!
Now our voyages of discovery have led us to ‘exoplanets’ — worlds beyond our Solar System. But we’re not traveling to them just yet. We’re using our telescopes to pay them a visit of sorts.
In 1992, we tracked down the first planet orbiting a distant star. Since then over 3,300 distant worlds have been recorded.
There are planets that have 60 times the mass of Jupiter, others are not much bigger than the Moon. Some are hot enough to melt steel, others are frostier than Pluto.
We’ve discovered exoplanets orbiting giant stars, orbiting dead stars and even “rogue” planets that don’t orbit any star at all, wandering through the galaxy alone.
Yet the most exciting exoplanets of all are those which are similar to our home planet. These are the planets that could carry life: rocky planets where the temperature is cool enough and also warm enough for liquid water to exist on their surface.
It turns out there is a planet somewhat like this orbiting the closest star to our Solar System! It’s just 4.243 light years away!
That’s kinda cool!
Proxima Centauri, a red dwarf or M dwarf star, orbits the double star we call Alpha Centauri or Rigil Kentaurus. Making its rocky new world the closest exoplanet to us.
It’s called Proxima b. Proxima a is the M dwarf.
It was discovered with the radial velocity technique by the Pale Red Dot team of European astronomers. They were using the HARPS spectrograph on the ESO 3.6 meter telescope at the La Silla Observatory in Chile.
That’s the 3.6 meter telescope’s observatory dome in today’s album artwork. You can also see a small inset graphic with some of the data the team acquired. The constellation Centaurus is labeled and Alpha & Proxima are both circled and labeled.
The team’s name is a take off from the Pale Blue Dot image of Earth, that Carl Sagan had Voyager 1 take, where our home planet was just a single blue pixel.
Our new neighbor is slightly more massive than the Earth, at least 1.3 times Earth’s mass, and it could be much more massive than that depending on its orbital inclination.
It orbits 7.3 million kilometers away from Proxima, even closer to its star than Mercury does to the Sun, circling it in just 11.2 days.
However, because its star is much cooler than the Sun, the new planet is still in what we call the “habitable zone” where liquid water is possible.
But is it comfortable enough for life? We’re not sure yet, but you can bet this is the next question astronomers will be trying to answer!
We can say a few things about the system right off the bat. It’s likely that the planet is either:
1. Tidally locked onto the star the way our Moon is locked to Earth, with one side facing us at all times.
or…
2. The planet is in a 3:2 resonance orbit with the M dwarf. It would rotate on its axis three times for every two orbits around its star. Our planet Mercury does this.
We don’t know if the planet has an atmosphere or not. If there is one and the planet is tidally locked, it might quickly freeze out on the back side as frost, leaving the planet without an atmosphere.
We can also say that Proxima Centauri is a flare star. American astronomer Harlow Shapley made this discovery in 1951. This is a variable star that puts out massive stellar flares and pours out beaucoup UV light & X-rays.
The fact that Proxima is a flare star complicated the data acquisition. The team had to monitor Proxima from several other observatories during the 90 days of data gathering.
This way flare events could be detected and the possibly contaminated data that was gotten during flares could be ignored.
This flare star business means that Proxima b is bathed in radiation and any life there will likely have to be underground. So don’t expect it to be anything more advanced than bacteria.
Honestly.
So despite what you’ve read online and in the papers, it’s not Earth LIKE. It’s Earth SIZED and in the habitable zone, but that’s as far as it goes. You probably wouldn’t want to live there.
Hey Here’s A Cool Fact:
There’s a plan to send a very, very tiny spacecraft to Proxima Centauri in 20 years. It’ll be called StarShot.
They’ll have to aim a little over 2° to the south west of Alpha to hit Proxima, though, it orbits that far away from it, about a tenth of a light year. They’ll want to launch a couple spacecraft to cover all the bases.
I wish them well.
Thank you for listening to the 365 Days of Astronomy Podcast!
End of podcast:
365 Days of Astronomy
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The 365 Days of Astronomy Podcast is produced by Astrosphere New Media. Audio post-production by Richard Drumm. Bandwidth donated by libsyn.com and wizzard media. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at 365DaysOfAstronomy.org or email us at info@365DaysOfAstronomy.org. This year we will celebrate more discoveries and stories from the universe. Join us and share your story. Until tomorrow! Goodbye!