December 24, 2019
Astronomers have found a planet the size of Earth "right next door".
Gee, I guess they didn't realize Venus was right over there.
According to Science Alerts:
"Here we present the discovery of GJ 1252 b, a small planet orbiting an M dwarf. The planet was initially discovered as a transiting planet candidate using TESS data," the researchers write.
"Based on the TESS data and additional follow-up data we are able to reject all false positive scenarios, showing it is a real planet."
GJ 1252 b is around 1.2 times the size of Earth, and around twice Earth's mass (so a bit denser than our home planet). It's orbiting a red dwarf star called GJ 1252, which is a little scrap of a thing, around 40 percent of the size and mass of the Sun.
The exoplanet whips around its star once every 12.4 hours - way too close for habitability, and probably tidally locked, where one side is always facing the star - but that tight orbit makes it attractive for another reason.
At just 66.5 light-years away, the system is at a close-enough distance that the star is bright enough for those follow-up observations we mentioned. In addition, the red dwarf is unusually calm for a star of its type; and the fact that the planet orbits it so often means there are plenty of opportunities to catch it moving in front of its host.
This is called a transit, and if the planet has an atmosphere, it will be back-lit by the star's light during transits, potentially allowing astronomers to see what's in it using spectroscopic observations.I wouldn't call sixty six and a half light years "next door", but it's close on an astronomical scale.
It would be absolutely uninhabitable - at least on the surface. A red dwarf usually has a strong solar wind, and that would strip away all the atmosphere. Also, almost all red dwarf stars are flare suns. Our own sun is a mild flare sun, nowhere near as active as most red dwarves. And at the close range of a planet like this, a solar flare would wipe out all life even if the place had an atmosphere.
The only really interesting thing about this discovery is that this planet is not a "super Earth' at four times the size of Earth but is just a little bit larger. And we were able to find it.
One thing is clear; the Star Trek vision of habitable planets all over the place just isn't so. There are lots of planets but I suspect finding truly Earthlike worlds is going to be really difficult.
We are going to need to learn to live in environments very different to what we have known. We are going to have to find a way to settle on moons and small planets, for instance, and live with low gravity. We are going to have to figure out how to live on asteroids and build space settlements. We can spin those for gravity (although a carbonaceous asteroid may just be a bunch of gravel and will fall apart if we try to spin it. We may eventually learn to live in zero g entirely. But we aren't going to be able to count on some pleasant planet that just happens to be a new Earth.
Of course, by the time we figure out a way to get between stars in years rather than centuries we'll have learned to live anywhere - and probably will be living everywhere.
Or, we could follow the advice of the modern luddites and give up technology, let ninety percent of our people die, and wind up living in a new neolithic. And then die when an asteroid or some other bad thing hits the Earth.
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