It seems like there’s a new Earth-like planet making the headlines practically every month
these days.
And, well, we found another one!
But even though we’ve found a lot of new planets lately, astronomers have reason to
be especially excited about this one.
Most of the exoplanets we find are either thousands of light years away or positioned
in a way that makes them tough to study — but this one’s in an almost perfect setup for
us to learn more about it.
Last week in the journal Nature, an international team of scientists announced they’d discovered
a new exoplanet called LHS 1140b, which orbits a red dwarf star only 40 light years away.
1140b is special because it’s relatively close to Earth and it transits, or passes
in front of, its star, which makes it much easier to study.
It was first discovered in 2014 as part of the MEarth Project, which searches for planets
around M dwarf stars, which are stars with less than 60% the mass of the Sun.
But it took another two years to confirm that the planet was really there.
So far, we know that 1140b is what’s called a super Earth: a common type of planet bigger
than the Earth but smaller than Neptune.
Super Earths are often gas planets, but 1140b is pretty dense: it’s more than six times
heavier than Earth, even though it’s only about 1.4 times as wide.
So the planet is probably made of rock or metal instead of gas, and its gravity is strong
enough that it could have an atmosphere, too.
But life there would still be a lot different from home.
For one thing, I hope you like cake and ice cream, because you’d celebrate your birthday
around once an Earth month.
The planet orbits its star every 25 days, and it also gets ten times closer to its parent
star than Earth does to the Sun.
But the star is a red dwarf, which is much cooler and dimmer than the Sun, so even though
it’s really close to its star, the planet actually gets less than half the light Earth
does.
That’s not a whole lot of light, but it could be enough for liquid water to exist
on the planet’s surface!
The star is also a lot more stable than many other red dwarfs, so it gives off much less
dangerous radiation.
Between its rocky surface, the amount of sunlight it gets, and the possible atmosphere, 1140b
would be a great place to look for signs of life — like certain kinds of molecules in
its atmosphere.
Luckily for us, 1140b’s orbit takes it between its star and Earth, which means we might be
able to learn more about its atmosphere based on the way light passes through it.
But astronomers won’t be able to study that atmosphere — or even confirm that it actually
exists — until October, when 1140b passes in front of its star again.
So we’ll have to wait until then to know more.
Meanwhile, much closer to home, the International Space Station might be getting a new neighbor!
The China Manned Space Program is hoping to build a space station by 2022, and last week,
they accomplished a major step in that project: they launched their first cargo ship.
The ship, called Tianzhou-1, launched aboard a Long March-7 Y2 rocket on April 20.
It’s the latest in a series of successful missions:
Since 2003, when they sent their first astronauts to space, China’s done a bunch of crewed
missions.
And in 2011, they launched Tiangong-1, a space laboratory that operated for four and a half
years.
That went well, so they did it again and launched another lab, Tiangong-2, last September, which
is still in orbit.
In October, two astronauts even lived and worked in the space lab for 33 days, completing
China’s longest crewed mission so far.
These labs are much smaller than China’s planned space station, but they've been an
important building block in getting ready for that next project.
Now, you can’t really have a space station without being able to send up food and supplies,
so testing Tianzhou-1 in orbit is the next step.
They’ve already done more than 600 ground tests of the docking hardware, so the main
goal of this mission is to perform docking and refueling tests between the cargo ship
and the Tiangong-2 lab.
If all goes well, Tianzhou-1 will be able to use this docking technology to bring up
to 6000 kilograms of food and supplies to the future space station.
Once it’s completed, the station will orbit 393 kilometers above the Earth, which is about
the same height as the ISS, which orbits at about 400 kilometers.
But just because the two stations will share the same traffic lane doesn’t mean they’ll
crash into each other: That’s why we have orbital engineers.
China’s space station will also be much smaller — only 60- to 70,000 kilograms,
which is about a sixth of the mass of the ISS.
But everyone has to start somewhere, and China has big plans for their future in space.
Who knows?
Maybe someday they’ll visit our new planetary neighbor 1140b!
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