Last week, a celebrity favorite here at SciShow -- the visionary billionaire Elon Musk -- displayed
the first crewed spacecraft to be unveiled in the U.S. since 1981.
Meanwhile, a planet somewhat like Earth, only waaaay bigger, is making heads get scratched
and minds be blown as it challenges our theories about how planets form -- and how the universe
itself evolved.
I'm Reid Reimers. Welcome to SciShow Space News.
[INTRO]
On Monday, astronomers from the Harvard-Smithsonian Center for Astrophysics announced they'd discovered
a whole new class of exoplanet -- a kind of giant terrestrial world they call a mega-Earth.
This new category is based on a planet first observed by the Kepler Space Telescope in
May 2011, an alien world known as Kepler-10c.
When Kepler observed the planet transiting across its star, Kepler 10, astronomers measured
it to be about two-and-a-half times the size of Earth.
And because of its size, they assumed it was a type of planet called a Mini-Neptune, with
a terrestrial core a little bit denser than Earth's and enough gravitation to accumulate
a thick atmosphere of hydrogen and helium.
But astronomers followed up their Kepler observation with another instrument in the Canary Islands,
known as the HARPS-N. And using its spectrometer, they found that the orbit of the star Kepler
10 was being pulled on by a truly massive object.
It turned out that Kepler-10c was about 17 times as massive as Earth -- much more than
anyone expected. And for anything to be that heavy, it's gotta be rock, all rock, and really
dense rock!
Which is kind of problematic, because that kind of density just...doesn't make sense.
First of all, there's not all that much solid material out there.
Hydrogen and helium are much more abundant than the elements like silicon and iron which
make rock.
And we've long thought that planets with about ten times the mass of Earth would necessarily
attract thick layers of gas with their gravity.
So we've been assuming that all the massive planets we find are gas giants like Jupiter.
But Kepler-10c challenges that assumption, and astronomers aren't sure how that can be.
It also challenges our theories about how the whole universe formed. Early in the universe's
14 billion year-life, everything was made out of the two lightest and simplest elements,
hydrogen and helium. Generations of stars fused those elements into heavier and heavier
atoms, eventually resulting in elements like iron that make up rock.
But the Kepler-10 star system formed 11 billion years ago, before the first generations of
stars had time to create such materials. Sooo where did the rock come from? Astronomers
are pretty dumbfounded.
So thanks a lot, Kepler-10c. I guess it's back to the drawing board.
Finally, NASA astronauts are done catching rides with the Russians.
Last week, SpaceX CEO Elon Musk unveiled the first manned American spacecraft to be available
since the closing of the NASA shuttle program in 2011.
Now SpaceX's Dragon V2 will be available to shuttle astronauts to the International Space
Station from US soil for the low price of twenty million dollars. It'll bring them back,
too--taking up to ten space trips in its lifetime.
It's a pretty awesome little machine. Capable of transporting seven people, the craft has
the first fully printed engine, called the SuperDraco, made with an alloy of nickel and
iron.
Dragon V2 has eight of these powerful and spontaneously igniting SuperDracos, which
Musk says will propel the craft with the maneuverability of a helicopter, allowing for precise docking
and re-entry.
And a state-of-the-art heat shield will protect the crew during re-entry into Earth's atmosphere.
Dragon V2 will take its first test flight later this year. And we can't wait!
Thanks for joining me for this update for the week's space news!
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