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It's only 42 years away. Bring towels.
November 9, 2012 3:05 AM   Subscribe

Well now, this is an interesting discovery... Reexamination of data collect through HARPS has resulted in finding three additional planets bringing the total to six. One of which is safely within the goldilocks zone of its star.
posted by michswiss (26 comments total) 10 users marked this as a favorite

 
Does anyone have any in-depth (but reasonably accessible for an amateur) guides to understanding the technology/science behind how distant star 'wobbles' and 'brightness shifts' are being used to established scientific consensus that we're finding planets around stars?

The precision of the instruments and experiments necessary for this astounds me and I'd like to learn more.
posted by panaceanot at 3:26 AM on November 9, 2012


... I guess I'm looking for something that James Gleick or Paul Davies might write about the HARPS link.
posted by panaceanot at 3:29 AM on November 9, 2012


The planet in question is in a star system 42 light-years away...RUH-ROH
posted by Smart Dalek at 3:36 AM on November 9, 2012


Just in time for Carl Sagan Day!
posted by Mezentian at 3:37 AM on November 9, 2012


42 you say?
posted by CautionToTheWind at 3:49 AM on November 9, 2012 [1 favorite]


Hey bestest mod team... happy to have my earlier comments removed... sincere yet unhelpful questions followed by a bunch of jokey memes might not be the best lead-in for this topic.
posted by panaceanot at 3:57 AM on November 9, 2012


Too bad for Mittens that they found Kolob just after the election, rather than before it.
posted by Wordshore at 4:22 AM on November 9, 2012 [1 favorite]


As many as we're finding, it seems like our current detection methods only work where the disk of the system is edge-on in our view, which has got to mean that we're still only able to look at a small sampling of stars. How many trillions of planets remain undetectable? It's like when a kid on a cave tour asks how many undiscovered caves there are & the guide stammers for a response.
posted by Devils Rancher at 4:23 AM on November 9, 2012


Launch the "come to Earth and kill us" ships now!
posted by pracowity at 4:32 AM on November 9, 2012


found at a period of 320 days.

PLANET WITH NO WINTER, SCIENTISTS SAY
SPRING COULD START RIGHT AFTER CHRISTMAS
posted by DU at 4:41 AM on November 9, 2012


Does anyone have any in-depth (but reasonably accessible for an amateur) guides to understanding the technology/science behind how distant star 'wobbles' and 'brightness shifts'

I don't know of any comprehensive guides, but the concepts you want to look up are spectroscopy, absorption lines & red & blue shift.
posted by Devils Rancher at 4:53 AM on November 9, 2012


Go to your library's online catalog and search for "exoplanets".
posted by DU at 4:56 AM on November 9, 2012


One of which is safely within the goldilocks zone of its star.


What sort of bears live on that planet is what I would like to know.
posted by louche mustachio at 6:22 AM on November 9, 2012


What sort of bears live on that planet is what I would like to know.

Living on a planet with seven times the mass of earth, terrifyingly strong, low-rider bears.
posted by Mooski at 6:32 AM on November 9, 2012 [7 favorites]


Does anyone have any in-depth (but reasonably accessible for an amateur) guides to understanding the technology/science behind how distant star 'wobbles' and 'brightness shifts' are being used to established scientific consensus that we're finding planets around stars?

I attended a lecture on the Kepler project once. As I recall, the brightness shift method is essentially this. Any planets, when they are between us and the star, will block some of the light reaching earth. So we do the following:

1) record light output of star every day
2) look for drop in output
3) if drops appear in a fixed periods, you have planets

Note that there may be several planets with different periods, and it will take potentially many years to gather the data since each planet will only occlude the star when it's at the point in its orbit that it's between us and the star.
posted by CheeseDigestsAll at 6:34 AM on November 9, 2012


Any planets, when they are between us and the star, will block some of the light reaching earth.

Logically, then, any system having planets that do not come between the primary and us remain unseen. Therefore, there are likely many, many more planets out there that we will not be able to discover with current technology.
posted by Guy_Inamonkeysuit at 6:54 AM on November 9, 2012


That's what I was talking about upthread. Both the doppler effect and the luminance detection modes require that we have an edge-on view of the planetary disk in question. So odds are slim that any given star, planets or no, is going to reveal its planets to us through our current detection schemes. Really, in the end, considering how many planets we've "seen" now, should point up that tiny sampling reveals how many more could be possibly, though undetectable. Surely there's math for this -- you could calculate the number of degrees of rotation vs. the angle at which we can detect interference (can't be more than a degree or two, if that?) to say what percentage of stars are potentially even observable.
posted by Devils Rancher at 7:34 AM on November 9, 2012


Guy_Inamonkeysuit: that's only one method. HARPS uses a different method - it measures the movement of the star due to the planet. This is still limited in inclination angles available, but not as limited as the occlusion method.

And yes, Devils Rancher - the mathematics for that part of the selection is straightforward.

I expect despite this the much more significant issue is the limited distances we can do this to. HARPS requires fairly bright stars to make its precision measurements, and even Kepler only gets out to a little over a kiloparsec in a relatively limited area I believe. The galaxy is 30 kiloparsecs across though... and then there's all those other galaxies.
posted by edd at 8:03 AM on November 9, 2012


I find it funny that the same urge I have to look up on Google Maps when a news story happens in a place I've not heard of (pull up GM, type in, go study the geographical context of the location) just happened here.

"Oh, possibly habitable planet, huh? We'll let me see what the driving time is."
posted by jscott at 8:07 AM on November 9, 2012


Confused. According to Apple Maps, these three new planets lie just outside Ann Arbor, off I-94.
posted by Wordshore at 8:15 AM on November 9, 2012 [1 favorite]


jscott: "Oh, possibly habitable planet, huh? We'll let me see what the driving time is."

At 60 mph, about 469.75 million years. A bit more if we stop to eat.
posted by hangashore at 8:44 AM on November 9, 2012


At 60 mph, about 469.75 million years. A bit more if we stop to eat.

Hollow out an asteroid and fill it with Red Bull. We're gonna need a bigger iPod...
posted by CynicalKnight at 9:16 AM on November 9, 2012


The country which is favorite to first announce contact with alien life ... is not the USA.
posted by Wordshore at 9:19 AM on November 9, 2012


>Living on a planet with seven times the mass of earth

It's 1.9g - you'd have to be pretty strong to walk around with a double of yourself on your shoulders. But think of all the real estate in a planet that size. Maybe exoskeletons are the key.
posted by stbalbach at 10:17 AM on November 9, 2012


Does anyone have any in-depth (but reasonably accessible for an amateur) guides to understanding the technology/science ...

If you're in Canada, CBC's Nature of Things has an episode on Planet Hunters next week:
http://www.cbc.ca/natureofthings/episode/planet-hunters.html

If you're in Vancouver, MIT prof Sara Seager is speaking at SFU next Thursday afternoon and there are a few seats left. http://www.sfu.ca/dean-gradstudies/blog/events/SaraSeager.html
(The downtown Vancouver lecture on Friday night is long sold-out and waitlisted.)
posted by wenat at 1:28 PM on November 9, 2012


The surface gravity depends on the density. We don't know the radius so we can guess at a few possible average densities and calculate the gravity and surface area.

Density = same as Earth (5515 kg/m3); Surface Gravity = 1.9g; Surface Area 3.7 earths

But let say the planet was made of pure silicon, then:
Density = Silicon (2330 kg/m3); Surface Gravity = 1.08g; Surface Area 6.5 earths

Or maybe it's a water world
Density = Water (1000 kg/m3); Surface Gravity = 0.61g; Surface Area 11.4 earths

So if the planet was a mixture of silicate rocks and ice without a significant iron core it might well have earth like gravity.

A planet with 7 times earths mass with a surface gravity of 1g would need an average density of about 2100 kg/m3 and would have a surface area equal to 7 earths.
posted by Long Way To Go at 1:34 PM on November 9, 2012 [1 favorite]


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