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Earth-like planet just 12 light-years away (sciencemag.org)
38 points by gautamc on Dec 19, 2012 | hide | past | web | favorite | 18 comments

Before reading article: "Earth-like, eh. This is going to be yet another one of those link bait articles identifying a gas giant closely orbiting some sun as being earth-like."

Article: "slight changes in Tau Ceti's motion through space suggest that the star may be responding to gravitational tugs from five planets that are only about two to seven times as massive as Earth"

After reading article: "I was wrong, there wasn't even a confirmed planet involved."

when you are looking that far away, you can't see any planets. They are not light source like stars.

The only way to figure out whether star has any planets around is to measure and interpret periodical gravitational vibrations.

You are of course right about 1 of the 3 methods of finding planets around distant stars but I feel droithomme was more commenting on the total disconnect between the post title and the actual discovery which is nothing like 'earth-like planet discovered around a star 12 light years away'.

Apologies for being a pedant

Thanks, yes that's correct. The key detail from the quote pull was "suggest", I didn't intend to indicate that this general method is detection is invalid.

The details in the article came down to they were pulling signal out from deep within noise in a way that other planet finders were skeptical of: "They're really digging deep into the noise here. The community is going to find it hard to accept planet discoveries from signals so deeply embedded in noise."

Even the researchers themselves are quoted as saying they don't consider anything here proven, they are just seeing if anyone else wants to have a go at finding further confirmation or disproof: "We felt that the best thing to do was to put the result out there and see if somebody can either independently confirm it or shoot it down."

The researchers themselves have not made the claim of finding an earth like planet around Tau Ceti at all. It's not been established or accepted by experts in the field that there are planets around this sun, what their orbits are, their composition, or that they are "earth-like" in a way that any non-specialist reader would interpret "earth-like". Even the authors don't make those claims. Maybe someday those things will be confirmed or disproved. Today is not that day.

The journalist is aware of this too. At the end of the article he says "If the planets exist...", acknowledging it is not established at all, before then engaging in fanciful speculation that is unlikely to appear in a reputable science news source with a competent editor: "That may just explain why no one from Tau Ceti has ever contacted beings as primitive as us."

Unless the planets happen to orbit very stable stars in the plane that sometimes puts them between earth and their star. With Kepler and some earth-bound telescopes you can discern the brightness dips from these and sometimes glean minimal spectroscopic information on the planet. Direct imaging is possible with interferometric methods and some more innovative approaches [1] but require funding.

[1] http://en.wikipedia.org/wiki/New_Worlds_Mission

title is linkbait-y.

It's saying that there MIGHT be some planets orbiting that star, but there's so much noise in the data that it's likely just noise and nothing else.

That is not how I read it at all.

The scientists took a lot of measurements over a long period, and carefully tried to remove as much noise as possible. After this, they think the remaining perturbation can be explained by a system of smallish planets. One of those planets looks like it could support life in a similar way to how Earth supports life.

There is a chance this perturbation is just noise, but the authors obviously think that the planetary system hypothesis is strong enough to ask the community for collaborating or contradictory data.

The title could have hedged its bets by adding 'might be' or similar terminology, but I honestly don't think that adds much to the conversation.


I was going to include the famous "title ending in '?'" rule of thumb, but missed the fact that the actual article and the title here differ. The actual title is of course "Another Earth Just 12 Light-Years Away?" which makes much more sense given the content.

The submitted title, I thus agree, is linkbaity.

You see, this is the benefit you get from not having experienced the 70's, everyone knows that the Grey Aliens come from Tau Ceti. Sheesh.

Fortunately, I think the last bit of annoying 70's alien phenomena will be past on December 22nd. Then we can all put to rest any question there might have been that we were visited by ancient astronauts.

"Then we can all put to rest any question there might have been that we were visited by ancient astronauts."

Good luck with that.

If I did my calculations right then at 17,000 mph it would take 474,568.57 years to get there.

After a journey that long, it would be a bit of a downer if the planet turned out to just have been noise!

Considering that is not even reaching Earth's (surface) escape velocity, the duration should not be a problem. The pioneer probes are doing about twice that now, the Helios probes come closer to 9x that at their closest approaches to the sun.

I wonder if SETI focuses in the direction of Earth-like planets, or if they just search the entire sky?

This should give you an idea:


at my old favorite Amstrad's game title star ;-)

If we can reach 10% of the speed of light in a few hundred years, maybe at that time we can have one-way missions like the suggested Mars trips now.

Such a trip might require a fusion power source though.

Wonder what crew size you would need to ensure genetic stability and the certainty that the crew would hang in there until the destination. It couldn't be a democratic arrangement onboard for sure.

I suspect for long term, generational-distance missions, stasis would be a far preferred option.

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