Earth to...Earth? Are you there?

jasamaman writes "So far all the planets found outside our solar system have been gas giants. So they are not habitable, and couldn't really hold life as we know it. But "planet hunter" David Charbonneau is looking for another planet just like Earth, and claims that astronomers are "very close"."

Comments

Re:How does he know?

[CrazyDwarf]

I'm glad you posted the section you did here, as I didn't remember his exact words (and I can sometimes be a stickler for comparing what he said to what people think he said.) It says, "We are close to being able to find Earth-like planets." He doesn't say we're close to finding one, just that we're close to being able to find one. That's quite a big difference, especially when you consider that space is mostly empty. It could be 20 years after we are able to find one that we actually do.

Just to kind of explain that to some of our slower readers... and this is in no way accurate, but just an example to help understand... if putting a coke bottle on the end of a telescope enables us to detect Earth-like planets, then we still have to search the skies with that telescope. That could take a long time, with the vastness of space.

Re:Close, but not that close

[Royster]

First, we need to find an extra-solar system in which Earth-sized planets exist. It's now believed that these are fairly few and far between. The reason is that a vast majority of the gas giant systems we've discovered so far have their gas giants in either really close orbits to their stars, or are highly eliptical with passes close to their stars. In these situations, Earth-like planets would likely be tossed into their stars, or more likely, tossed into open space, by the gravitational effect of the giants.

Oh, bullshit.

The methods we have used until now to find extra-solar planets are extremely biased to find (a) large planets, (b) very close to the star and (c) in highly elliptical orbits. To make conclusions about the distribution of Earth-like planets from biased samples is foolhardy.

It's as if you decided to count species by sitting in one place in the woods looking through a pair of binoculars. Sure, you would see all of the large mammals and birds that happened by, but you'd miss the vast majority of species by seeing hardly any of the incects (maybe a few fireflies if you were savvy enough to recognize them as animals) and none of the water dwelling animals. You conclusions about the distribution of species would be worthless because you saw only the easiest animals to spot.