Next year there is a plan to send a space telescope to L2 with the main objective being to search for Earth-like planets around Sun-like stars in the habitable zone.<p>Like Kepler and TESS telescopes it will use the transit method to find new exoplanets, but unlike any mission before, it's going to look at the same spot in the sky for over a year. Super excited to see what data it brings back to us.<p>The telescope is called PLATO ( <a href="https://en.wikipedia.org/wiki/PLATO_(spacecraft)" rel="nofollow">https://en.wikipedia.org/wiki/PLATO_(spacecraft)</a> )<p>I contributed to the project a few years back, very happy to answer any questions.
Let me remind you guys that "just 20 light years" = roughly 200 trillion kms. At the speed of voyager 1, it takes roughly 1600 yrs to travel 1 trillion kms. 200 trillion kms would take 320,000 years to reach there. Even if you increased the speed of voyager 1 by 10 times, it would still take 32000 years to reach. We really need to up the speed by a factor of 10000 before we can get anywhere close to human lifetime achievable travel times.
The existence of the Super-earth was not directly observed, but was instead inferred by the gravitational lensing of all the democracy[0] being spread in a sphere around the planet.<p>[0] <a href="https://helldivers.fandom.com/wiki/Super_Earth" rel="nofollow">https://helldivers.fandom.com/wiki/Super_Earth</a>
Highly recommend listening to In our Times (BBC) episode "The Habitability of Planets" that was aired last month.<p><a href="https://www.bbc.co.uk/programmes/m0025vvd" rel="nofollow">https://www.bbc.co.uk/programmes/m0025vvd</a>
<a href="https://www.aanda.org/articles/aa/full_html/2025/01/aa51769-24/aa51769-24.html" rel="nofollow">https://www.aanda.org/articles/aa/full_html/2025/01/aa51769-...</a> (<i>"Revisiting the multi-planetary system of the nearby star HD 20794"</i>)
"the new planet ... tak[es] 647 days to complete an orbit around its star, 40 days less than Mars. This orbit places it within the habitable zone of the system, meaning it is at the right distance from its star to sustain liquid water on its surface"<p>1. That orbit make it really cold relative to Earth - like Mars is.<p>2. It doesn't say that the planet has a human-breathable atmosphere; it might, but it might not - like Mars.<p>Also,<p>3. Gravity force is g<i>M</i>m/R^2 right? Let's say same density as earth, and that density is uniform. Now, the mass relates to the radius by R^3, so the gravity force will be higher by 6^{1/3}, or about 1.817x higher than Earth.<p>So, would you say this is a habitable planet? It's kind of a stretch.
My napkin math says the surface gravity would be around 30 m/s2.<p>I'm not looking forward to a visit. Maybe it has a large moon like Earth. If it is in the same proportion as ours, the moon might even be friendly to humans.
So can we now have a trio of ulra large optical telescopes, flying in an ultra high resolution formation, used to create images useing optical interferometry, now. Now? Want!
And if the international astronomic comunity drags there feet , advocating for more "science" missions, and getting proof of exo habbitats befor they can look for them, tenures safe, then lets defund the whole mess, and build telescopes at scale, get optical data, and THEN they can theorise in they very own arm chairs at home, about all the anomalies they want.
I'm sure the aliens reading that are saying "Thank god! They aren't coming here." :-)<p>But on a more serious note, this is some great science. I am super impressed by how sensitive the instruments need to be to chart the fluctuations due to mass here at 20 light years. I'm always on the fence about whether or not we should focus a beam of RF with some modulation on it in their direction, on the one hand it would say "hello! we see you!" on the other that might not be a good idea.
Is there a way to estimate gravity on remote planets? Wouldn't the mass of this body, which is six times larger than Earth rule out the habitability?
"Intersecting" the habitable zone isn't the same as "within," I find it curious that discussion of the ramifications are far down, it seems pretty salient to me...<p>The idea of an ecosystem hence culture for which a fundamental cycle is a year of fallow hibernation followed by a year of fertile plenty is quite compelling as a scifi trope though.<p>Me I'd name the planet Persephone for this reason.
The Raleigh criteria for 1km resolution at 20ly requires an interferometer with a baseline of 120,000km. That’s about a third of the way to The Moon or 10x the diameter for The Earth.<p>How far away is such technology?<p>For 1000km resolution the requirement is three orders of magnitude smaller, or ~120km. Could such a device be terrestrial?
Since each star is different, it seems like the inner and outer limits of each habitable zone would also be different for various stars. Is it just the mass of the star that determines this, or are there other factors?
Just a reminder that if, for some reason, we discover technological civilization on that planet, it's very, very bad news for us as a species.<p>I'm talking about the Fermi Paradox. Basically, given all the stars we can see and that we see planetary systems around virtually every star we look at, then a decent portion of them should have rocky planets in the habitable zone. A portion of those should have the conditions conducive to life. A certain percentage of those will develop technological life.<p>Each of these steps that reduces the likelihood of technological life is called a "filter" in Fermi Paradox parlance. These vary from small filters to so-called "Great Filters". The idea of a Great Filter is almost no species gets beyond it. All the heavy elements we have access to might be a Great Filter.<p>As a reminder, anything heavier than helium is made in a star. Normal stars only make elements up to iron. It takes a supernovae or a neutron star merger to make elements heavier than this. So, for Earth to exist as is, there had to be a star relatively close to us that was the right size to basically go supernova. It had to be born, live and die before the Sun formed and that material had to be captured in our proto-planetary disk and ultimately become part of Earth.<p>We have thus far found absolutely zero evidence of these alien civilizations so the question is why? If we find an equivalent civilization to us on a really close neighbour then by Bayesian reasoning, it means it's significantly more likely that a Great Filter is still ahead of us.
lets have a look <a href="https://en.wikipedia.org/wiki/Solar_gravitational_lens" rel="nofollow">https://en.wikipedia.org/wiki/Solar_gravitational_lens</a>
Only 20 lightyears sounds good, and the elliptical orbit within the habitable bounds sounds also good, comparable to our summer-winter shifts. Now they need to detect water
My second, more intelligent, rational take: goodness, that's exciting! I can't wait to see more research as it follows.<p>My first, drowned-in-doom-news take: can I move there? Immediately?
Super Earths are a one-way trip right? If you land, you can never take off again due to the tyranny of the rocket equation.<p>Barring science fiction, of course.
> HD 20794, a star with a slightly lower mass than the Sun and located just 20 light-years away<p>I'd prefer to hear about interstallar travel news rather than DeepSeek ones :-) The pale-blue-dot is really generating anxiety :-/