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We’ve found an Earth-like planet orbiting a star RIGHT NEXT DOOR TO OUR SUN!
Pack your bags, kids!
Hello there soon-to-be Proxima Centurians!
Trace here for DNews.
A few weeks back we started hearing rumors, really exciting rumors tales of the discovery
of a planet… and then we freaked out.
Because those rumors are true!
Today, astronomers announced our closest neighbor star, Proxima Centauri, has a rocky planet
orbiting in the habitable zone.
Ladies and gentlemen, this is Proxima b!
The planet is around 30% more massive than Earth and is mind-blowingly close to its star.
It only takes a little over 11 days for the planet to complete a single orbit -- it's
95 percent closer to Proxima than we are to our sun. It doesn't burn up because Proxima
is a red dwarf star, so it's much cooler and smaller than our sun.
The habitable zone around any star is the distance at which a planet needs to orbit
that’s not too hot and not too cold for liquid water to exist on its surface. As
far as we can tell, where there's water there's a possibility for life.
This is why astrobiologists get excited when they find exoplanets in habitable zones.
Just because a planet is in a habitable zone, though, doesn't mean we can live there.
And even though liquid water could exist on Proxima b, that doesn't mean it has any.
On top of that, red dwarf stars like Proxima Centauri emit more intense x-ray flares, and
ultraviolet energies than our own sun.
So, while we probably can't live there, it's exciting because before 1995 we'd never confirmed
a single exoplanet.
For all we knew, there were no planets out there…
Much less one RIGHT NEXT DOOR… only four point two light-years away!
Which is still far, but in astronomical terms that's ludicrously close.
So this is exciting for many reasons.
First, this Proxima b is the closest exoplanet beyond our solar system. Which is great.
But, the fact that it’s Earth-sized AND orbits inside the habitable zone are both
Because c'mon.
There’s currently a lot of excitement for that possibility and plans in place to send
spacecraft to other stars, but we need new technology.
Our fastest current spacecraft would take about 80,000 years to get to Proxima Centauri,
but if we could go 10-percent the speed of light we'd cut that to 50 years.
We can't go that fast yet, but now maybe engineers and scientists will be inspired to figure
out how to get to this new planet.
Especially, if it’s Earth-like when we get there!
But that’s a big IF.
Though the media is calling Proxima b an “Earth-like” world, that’s not particularly accurate.
Just because a world is small and rocky like Earth, and orbits in the habitable zone, doesn’t
make it an oasis fit for life.
Just look at Mars and Venus; both of those are in our habitable zone and neither are
particularly Earth-like!
I already mentioned the powerful X-ray and ultraviolet radiation that Proxima b is likely
subject to… not great for biology.
But also, red dwarfs are known to flare regularly, blasting any planets with radiation.
This means the Proxima b would have to have a thick atmosphere and powerful magnetosphere
to protect it from damaging space weather if life were to flourish.
For now, we have no clue if it has either.
And then there’s the question of Proxima b’s really tight orbit.
When a planet orbits its star so closely, it will become “tidally locked” -- this
causes one hemisphere to constantly face the star while the other is in constant night.
That is VERY un-Earth-like, and can make for INSANE planetary weather.
One side cooks while the other freezes.
Look, in the end, this is still a VERY important AND historic discovery.
To have any world that just so happens to have any Earthy qualities on our galactic
doorstep is an incredible stroke of luck and will undoubtedly become a point of scientific
interest that could inspire Earthlings to see interstellar travel as a possibility.
When it comes to finding these tiny little planets, how do we know so much about them when
thay are so far away?
DiscoveryNews Space Producer Dr. Ian O'Neill explains that for you, here.
Special thanks to Dr. Ian O'Neill for all his help with this story!
We couldn't done it without you. You're a star, man!
How do you feel about this discovery?
Are you excited? Are you nervous? You want to go to there?
Let us know in the comments, and please subscribe. so you'll get more DNews



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Sh, Gang (Aaron) 發佈於 2016 年 8 月 25 日    Sh, Gang (Aaron) 翻譯    Mandy Lin 審核
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