NASA's Kepler space telescope finishes its original mission catalog NASA’s Kepler space telescope has finished cataloging possible planets in the direction of the Cygnus constellation. At a news conference today, NASA astrobuffs announced that the telescope has identified 219 new planet candidates. Ten are about the size of the Earth and are in the “Goldilocks zone” – they’re at the magic …
Although we've been gazing at the sky for as long as there have been people, we still know almost nothing about the universe we live in.
Kepler is doing a great job of advancing that knowledge, but this is the infancy of the planet-hunting sciences, so I wouldn't be at all surprised if we decide the types of planets are a sort of sliding scale rather than hard and fast rules.
Mini-Neptunes and Super-Earths might sort of merge into each other at some point.
Mini-Neptunes and Super-Earths might sort of merge into each other at some point.
I wonder if you're approaching this purely from the point of view of size rather than composition. The current thinking is that rocky planets tend to form in the inner system while gas and ice planets form successively further out, where it is much colder. This doesn't mean planets can't migrate from these positions, but a hybrid rock/ice planet would have to migrate while it was being formed -- it's more likely that a collision, a gravitational slingshot or close orbital resonance would break it up than move it. For example, look what Jupiter has done (and continues to do) to the material in the asteroid belt.
What if a planet formed in the inner system, was transposed by deflections in the early system into the outer systems (objects were much smaller then as the system was still forming), thus gaining itself a nice thick ice coat, then getting deflected into the goldilocks zone, where that nice thick coat mostly thawed?
A lazy hypothesis of how the earth got water.
There will be plenty of opportunities for more of this work. I'd like to see more work on getting into Earth orbit cheaply, and then some agreeable ways to move towards practical propulsion within the Solar System and then on an interstellar basis.
Perhaps, but in higher gravity environments they're likely to be smaller rather than larger.
Did I miss the point in the article where we accounted for the recognised bias in exoplanet discovery caused by the design of the Kepler mission and were thus able to draw accurate conclusions about the nature of planets in the galaxy as a whole? No, I thought not...
From the article: "Only exoplanets with orbital periods less than a hundred days were considered".
Turning the telescopes the other way around, this would mean that aliens would only find Mercury in our solar system. Not exactly a representative sample.
When the discovery technique relies upon a planet 'eclipsing' its star for us, then clearly we are going to miss a lot of larger orbit planets - plus of course, any system that's not on the 'right' orbital plane to pass between the star and us.
Hence whilst I think all the discoveries so far are wonderful, it seems a bit pre-emptive to start classifying a family tree of planets..
Fully agreed. I remember when this all started a large number of Jupiter sized planets (or even bigger) leading to many articles stating things like "Most other planetary systems do not contain earth sized planets" or "Alien life unlikely as other planetary systems made up only of gas giants".
Of course the real reason was that we simply couldn't detect Earth sized planets. We are still at a stage where there are huge constraints on our ability to detect them, and should wait until things improve before coming up with a classification system
From the article: "Only exoplanets with orbital periods less than a hundred days were considered".Turning the telescopes the other way around, this would mean that aliens would only find Mercury in our solar system. Not exactly a representative sample.
When the discovery technique relies upon a planet 'eclipsing' its star for us, then clearly we are going to miss a lot of larger orbit planets - plus of course, any system that's not on the 'right' orbital plane to pass between the star and us.
Hence whilst I think all the discoveries so far are wonderful, it seems a bit pre-emptive to start classifying a family tree of planets..
Yes, it's pre-emptive. But we classify what we can, and adjust the classification models as we learn more. That's kinda how things work.
Otherwise, at what point would you suggest we should we start classifying? How will we know when we have enough data that we can start work without being pre-emptive? Given the size of the galaxy, the biases inherent in every observation technique we've come up with, and the sheer difficulty in spotting objects like Sedna even when they're in our own system, it's clear to me that we're not going to be getting even close to an accurate picture of things for some time to come.
But even if we did have a chance of getting to a that point, we still shouldn't be waiting until we have a clearer picture of the real planet distribution before starting to classify them. The problem is that the picture can only become clear with the help of the classification work, so we really do have to do some classifying work up-front, even if we know it's going to be superseded.
Did I read correctly. every 4000 or so planets gives around 40 - 50 earth like candidates (call it 10% then)
And we looked just at Cygnus. (Assuming the same statistics apply to every other section of the galaxy)
So vast numbers of other planets must exist that could hold life and other human colonies.
"Did I read correctly. every 4000 or so planets gives around 40 - 50 earth like candidates" -- Avatar of They
You read correctly.
"(call it 10% then)"
You call incorrectly.
Pedantry aside, up voted because it is pretty amazing ... even at 1% that's a lot of other "Earths" and my mind is similarly blown.
Which suggests you're going to see planets with a certain set of properties.
And they are not likely to be those of an Earth.
That said this is an excellent result for a first serious pass at the problem. I fully expect that the team have learned a lot about what is possible in building a planet hunting telescope and how to improve such a mission. While the mission design seems unlikely to find very Earth like planets the statistical analysis of planets found versus types of sun surveyed should (if done carefully) reveal some interesting patters to help inform people who model how solar systems form.
However the Fermi paradox remains. It's definitely looking like there are plenty of planets on which life can evolve and at least some of them should get to be intelligent.
So why isn't anyone talking? Is the human race too early, or too late to the party?
So why isn't anyone talking?
Perhaps they've listened to our radio and TV broadcasts, and are just waiting for the box set?
Or more likely, they're hiding.
Or they've decided to cancel their subscription, and have despatched the war fleet. Simon Cowell has doomed us all!
"Or they've decided to cancel their subscription, and have despatched the war fleet. Simon Cowell has doomed us all!"
Presumably an alien civilization capable of interstellar travel will be technologically and culturally much more advanced than us, and so most likely have a much more sophisticated sense of fashion. Most of us will survive the encounter, but high-waisted trousers will be history...
"It is estimated that only 1 per cent of stars host super-Jupiters, planets that are more massive than Jupiter with short orbital periods of about 10 days."
Even if you read this at 100 days that's a very short orbital period and hence a very close orbit for a Sun sized star and most likely a little toasty for a gas giant. Since I'd expect there to be a lot more further out, where they didn't look, I'm not sure this estimate is particularly useful.
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