Monday, June 16, 2008 | Reason : In the News | print version

Astronomers find batch of 'super-Earths'

by The Age

Thanks to Andrew Heggie for the link.

http://www.theage.com.au/world/astronomers-find-batch-of-superearths-20080616-2rjd.html

Astronomers find batch of 'super-Earths'

An artist's impression of the trio of super-Earths discovered by an European team using the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, Chile, after five years of monitoring. Photo: HO

European researchers today said they discovered a batch of three "super-Earths'' orbiting a nearby star, and two other solar systems with small planets as well.

They said their findings, presented at a conference in France, suggest that Earth-like planets may be very common.

"Does every single star harbour planets and, if yes, how many?'' asked Michel Mayor of Switzerland's Geneva Observatory.

"We may not yet know the answer but we are making huge progress towards it,'' Mayor said in a statement.

The trio of planets orbit a star slightly less massive than our Sun, 42 light-years away towards the southern Doradus and Pictor constellations.

A light-year is the distance light can travel in one year at a speed of 300,000km per second - or about 9.5 trillion kilometres.

The planets are bigger than Earth - one is 4.2 times the mass, one is 6.7 times and the third is 9.4 times.

They orbit their star at extremely rapid speeds - one whizzing around in just four days, compared with Earth's 365 days, one taking 10 days and the slowest taking 20 days.

Mayor and colleagues used the High Accuracy Radial velocity Planet Searcher or HARPS, a telescope at La Silla observatory in Chile, to find the planets.

More than 270 so-called exoplanets have been found. Most are giants, resembling Jupiter or Saturn. Smaller planets closer to the size of Earth are far more difficult to spot.

None can be imaged directly at such distances but can be spotted indirectly using radio waves or, in the case of HARPS, spectrographic measurements. As a planet orbits, it makes the star wobble very slightly and this can be measured.

"With the advent of much more precise instruments such as the HARPS spectrograph ... we can now discover smaller planets, with masses between 2 and 10 times the Earth's mass,'' said Stephane Udry, who also worked on the study.

The team also said they found a planet 7.5 times the mass of Earth orbiting the star HD 181433 in 9.5 days. This star also has a Jupiter-like planet that orbits every three years.

Another solar system has a planet 22 times the mass of Earth, orbiting every four days, and a Saturn-like planet with a three-year period.

"Clearly these planets are only the tip of the iceberg,'' said Mayor.

"The analysis of all the stars studied with HARPS shows that about one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital periods shorter than 50 days.''

Reuters

Add to del.icio.us Posted: Monday, June 16, 2008 | Permalink

Comments 1 - 50 of 92 |

Reload Comments | Back to Top | Page Numbers

1. Comment #193874 by leodavinci on June 16, 2008 at 7:19 am

Cool, or should i say Goldilocks Zone.

Other Comments by leodavinci

2. Comment #193881 by MarcLindenberg on June 16, 2008 at 7:32 am

Wow, so now when Earth is dying we will have a place to go :P

It's pretty cool to think that there might be lots of Earth-like planets out there...

Other Comments by MarcLindenberg

3. Comment #193895 by Gwaihir on June 16, 2008 at 7:45 am

I have been meaning to ask my pastor what the catholic church's stand is on exoplanets. Ha!
If we can find earth-like planets orbiting nearby stars, then there are possibly billions more, or even trillions more. The universe is a kind place.

Other Comments by Gwaihir

4. Comment #193900 by pwuk on June 16, 2008 at 7:47 am

That'll be handy, for when we become immortal :-)

Other Comments by pwuk

5. Comment #193903 by robotaholic on June 16, 2008 at 7:51 am

more places to strip-mine!

Other Comments by robotaholic

6. Comment #193918 by SPS on June 16, 2008 at 8:06 am

Is it too early to have my thumb out?

Other Comments by SPS

7. Comment #193925 by bugaboo on June 16, 2008 at 8:11 am

can someone explain to me (or point me in the right direction to find out)why the orbits are of such short duration?

Other Comments by bugaboo

8. Comment #193942 by schmeer on June 16, 2008 at 8:26 am

"can someone explain to me (or point me in the right direction to find out)why the orbits are of such short duration?"

Most likely it is because the "wobble" in brightness that indicates a planet is present is much easier to see when the variation occurs over a shorter time period. To find a planet with a year comparable to our own, you'd have to watch it for years. If the planet orbits in a few days you can see the change in brightness in a week's work.

Other Comments by schmeer

9. Comment #193947 by Quetzalcoatl on June 16, 2008 at 8:30 am

Bugaboo-

as to the reason why the planets actually have such a short orbit, they could have formed that close in to the star, but it's more likely that they formed further out and their orbits were disturbed, perhaps by a rogue gas giant, sending them spiralling in towards the sun.

Other Comments by Quetzalcoatl

10. Comment #193948 by EvidenceOnly on June 16, 2008 at 8:32 am

Although this should cause religious people to reflect on the silliness of their believes that god (which one?) created us and that he/she/it has a plan for us, most will probably conclude that it is the devil who is corrupting us with science or that it is the devil who is creating these fake images to make us doubt god.

This would imply that the devil is technologically superior to god which would make the devil god himself/herself/itself.

This would be just funny if the religious would keep religion to the privacy of their own home and stay out of politics.

Other Comments by EvidenceOnly

11. Comment #193953 by bugaboo on June 16, 2008 at 8:36 am

Schmeer and Quetz

Thanks. Another wobble hypothesis-i like it!

Other Comments by bugaboo

12. Comment #193958 by moderndaythomas on June 16, 2008 at 8:43 am

42 light-years away towards the southern Doradus and Pictor constellations.

That's a Sunday drive.

Other Comments by moderndaythomas

13. Comment #193963 by Kentrel on June 16, 2008 at 8:48 am

"This would be just funny if the religious would keep religion to the privacy of their own home and stay out of politics."

As you are the first person to mention religion in this thread I feel I should point out to you, that it would be also nice if in a science thread, some people wouldn't keep dragging religion into it...

Other Comments by Kentrel

14. Comment #193967 by Steve Zara on June 16, 2008 at 8:51 am

Comment #193947 by Quetzalcoatl

as to the reason why the planets actually have such a short orbit, they could have formed that close in to the star, but it's more likely that they formed further out and their orbits were disturbed, perhaps by a rogue gas giant, sending them spiralling in towards the sun.

Absolutely.

There is another factor at work here too. These are simply the Earth-like planets we can detect. It might be more common for Earth-like planets to be at Earth-like distances.

Other Comments by Steve Zara

15. Comment #193972 by Quetzalcoatl on June 16, 2008 at 8:55 am

Steve-

oh, definitely. We'll be finding Earth-size planets in Goldilocks zones within the next decade or so, probably. A few years ago, we couldn't even detect large gas giants. Science moves on!

Other Comments by Quetzalcoatl

16. Comment #193973 by Steve Zara on June 16, 2008 at 8:58 am

Comment #193972 by Quetzalcoatl

Heh. Don't get me started on the subject of Goldilocks zones!

I can thoroughly recommend "Evolving the Alien" by Jack Cohen and Ian Stewart. It puts to rest the idea of the Goldilocks zone.

Even an extra-solar planet with no warmth other than internal radioactive decay could be as full of (simple) life forms as the Earth. (Being extra-solar, it would have a thick atmosphere of insulating hydrogen, and the surface temperature would be nice and warm for billions of years)

Other Comments by Steve Zara

17. Comment #193980 by Quetzalcoatl on June 16, 2008 at 9:01 am

Steve-

well, let's face it, when we have the ability to, everyone will be looking in the Goldilocks zones anyway. And they are at least the best place to look to find planets capable of supporting us, ie with liquid water and reasonable temperatures.

I'll check out that book- I enjoyed The Science of Discworld books they wrote.

Other Comments by Quetzalcoatl

18. Comment #193981 by passutoba on June 16, 2008 at 9:02 am

sorry if this a dumb question, but would the short orbit time mean they also rotate faster on their axis?

Other Comments by passutoba

19. Comment #193987 by Quetzalcoatl on June 16, 2008 at 9:07 am

Passutoba-

not necessarily. Venus, for instance, has a very long day compared to ours. Depending on the type of star, it's also possible that the planets are tide-locked so that one side permanently faces the star.

Other Comments by Quetzalcoatl

20. Comment #193991 by black wolf on June 16, 2008 at 9:10 am

Strategy: convince the nutters that those planets are the place God meant them to live on, have them pool their billions, build a generation ship and off they go. I'd like to keep Earth for reasonable people.

Other Comments by black wolf

21. Comment #193993 by Steve Zara on June 16, 2008 at 9:11 am

Comment #193980 by Quetzalcoatl

well, let's face it, when we have the ability to, everyone will be looking in the Goldilocks zones anyway.

Yeah, that is inevitable :)

And they are at least the best place to look to find planets capable of supporting us, ie with liquid water and reasonable temperatures.

Actually, that probably isn't true. Earth was only what we consider "Earth-like" for about the past 600 million years - a tiny fraction of its existence.

There is most likely far more warm water in the underground seas of gas giant moons, the result of tidal heating.

Other Comments by Steve Zara

22. Comment #193997 by wiz220 on June 16, 2008 at 9:13 am

The most likely reason for finding planets with short periods is that they are easier to detect with both the wobble method and the blocked light method. If the planet had an orbit that was very long (a year or more) you have to observe the star for a longer time to see the wobble caused by the planet's gravity. Also, you would have to be looking at the star at JUST the right time to see the light from the star dim due to a planet passing between us and the star (if you were not using the wobble detection method.

If the planet is orbiting quickly the wobble is more pronounced because it's happening at a higher rate. You would also have a better chance of seeing the star dim because of a planet passing in front of it (second detection method).

Other Comments by wiz220

23. Comment #194000 by Quetzalcoatl on June 16, 2008 at 9:16 am

Steve-

well, yes, but by "supporting us" I meant Earth-like worlds that we can actually walk around on with maybe a pressure suit or something for the atmosphere. In practical terms they would be easier to settle than a gas giant moon.

Other Comments by Quetzalcoatl

24. Comment #194008 by Steve Zara on June 16, 2008 at 9:24 am

Comment #194000 by Quetzalcoatl

Ah! I see what you mean.

It still probably isn't going to be likely. We would have a lot of problems living on Earth more than a hundred or so million years ago, as the oxygen varied so much.

Other Comments by Steve Zara

25. Comment #194012 by Quetzalcoatl on June 16, 2008 at 9:30 am

Steve-

we're getting into sci-fi territory now! You raise a good point- many sci-fi novels don't cover the idea that different oxygen levels make it unlikely that very many earth-size planets will be sufficiently earth-like for humans to live on without either domed colonies or genetic modification. Even I didn't think about it in my books :(

Other Comments by Quetzalcoatl

26. Comment #194013 by mesomodel on June 16, 2008 at 9:30 am

Comment #193981 by passutoba

sorry if this a dumb question, but would the short orbit time mean they also rotate faster on their axis?

No, not necessarily. Different phenomena.

Other Comments by mesomodel

27. Comment #194032 by entheogensmurf on June 16, 2008 at 9:52 am

MarcLindenberg,

Earth is dying, or I should say we are destroying (killing) the planet.

I do agree that it's cool that Earth-like planets are popping up. Now we just need the engines, the ability to survive a trip that lasts over 40 years and the ability to terraform.

Other Comments by entheogensmurf

28. Comment #194035 by Steve Zara on June 16, 2008 at 9:58 am

Comment #194032 by entheogensmurf

Earth is dying, or I should say we are destroying (killing) the planet.

I think that is a bit strong. If millions of years of continent-sized lava flows in the Permian could not destroy life, and if an asteroid collision with a force of millions of nuclear weapons at the end of the Cretaceous could not do it, then we can't.

Other Comments by Steve Zara

29. Comment #194037 by evolver23 on June 16, 2008 at 10:03 am

Question:

Is the word "super-Earths" used simply because of their size? Are the planets known to be rocky, rather than gas giants? Or have the researchers been able to analyze the chemical composition of the planets' atmospheres via spectroscopy? I guess I'm just wondering what exactly the distinction is between these exoplanets and previously discovered ones.

Other Comments by evolver23

30. Comment #194044 by moderndaythomas on June 16, 2008 at 10:24 am

I can thoroughly recommend "Evolving the Alien" by Jack Cohen and Ian Stewart. It puts to rest the idea of the Goldilocks zone.

This brings to mind something that I had read from one of Sagans books. In it he imagines what life evolving on (in) a gaseous planet such as Jupiter would be like.

I recall thinking that it would be difficult to do anything when you couldn't set foot on a crusty surface, but just think about the albatross.
Here's a bird that lives in the windiest places on the earth. It can stay aloft indefinitely. It needs not expend energy in flight, all it has to do is extend its wings and the wind does all the work.

Other Comments by moderndaythomas

31. Comment #194049 by aussieatheist_111 on June 16, 2008 at 10:31 am

Strategy: convince the nutters that those planets are the place God meant them to live on, have them pool their billions, build a generation ship and off they go. I'd like to keep Earth for reasonable people.

No - that's unfair on those already living there!

Other Comments by aussieatheist_111

32. Comment #194063 by bugaboo on June 16, 2008 at 11:13 am

30. Comment #194044 by moderndaythomas

I was fortunate enough to attend a series of lectures (Gifford lectures) given by Carl Sagan in Glasgow some twenty years ago. I remember he speculated on life forms evolving on gas giants, "floaters" I think he called them. I havent kept up with advances in astronomy (hangs head in shame), save for simply marvelling at the images from hubble etc.

The book Steve Zara recommends looks good so just ordered it from Amazon. Must catch/keep up.

Other Comments by bugaboo

33. Comment #194099 by squinky on June 16, 2008 at 12:17 pm

Moderndaythomas,

Your albatross analogy is wishful thinking. This bird doesn't lay eggs on the wind nor incubate them on a zephyr. The little hatchlings don't parachute around in little eggshells until their wings have strengthened to glide and not flap.

Until we understand how self-replicating molecules formed on the early Earth and where (assuming we ever do), the 'Goldilocks Zone' should be amended to the 'Bollocks Zone'. All the GZ means is that liquid water is present. So! Let's talk self-replicating RNA or how to create a working cell before we skip several billion steps to arrive at the impressively adapted Jovean Waterbird that effortlessly glides through hydrogen gas.

Other Comments by squinky

34. Comment #194103 by moderndaythomas on June 16, 2008 at 12:22 pm

squinky.
Your albatross analogy is wishful thinking.

Alas, you got me.

I wasn't claiming that they gave birth to flying eggs, merely that where there is wind, there is lift and where there is lift there is flight.
And here an organism can thrive.

edit: even a simpler organism. Which by the way might find it easier to stay aloft considering it is under less weight restrictions.

Other Comments by moderndaythomas

35. Comment #194134 by gr8hands on June 16, 2008 at 12:57 pm

In "Contact" the bible-thumping character's first reaction to the proof of extraterrestrial life was "we don't even know if they believe in god."

I somehow don't think reality will be much different, unfortunately. The religious will worry about evangelizing the planet, or contact with dangerous alien ideas and blasphemies.

Other Comments by gr8hands

36. Comment #194151 by davem on June 16, 2008 at 1:13 pm

@entheogensmurf:
"Now we just need the engines, the ability to survive a trip that lasts over 40 years and the ability to terraform."

... only to meet the natives, who are planning to do the same to us...

Other Comments by davem

37. Comment #194158 by moderndaythomas on June 16, 2008 at 1:25 pm

In "Contact" the bible-thumping character's first reaction to the proof of extraterrestrial life was "we don't even know if they believe in god."

One of the most frustrating parts to the book. I've always wondered what thought provoking fiction we all lost when Sagan died.

Other Comments by moderndaythomas

38. Comment #194176 by aheggie on June 16, 2008 at 1:50 pm

Given the tantalizing prospect of confirming other "Goldilocks planets", the beginning of life, in whatever soup, has yet to be sorted out despite fascinating experimental attempts.

I am sure many of us keep a keen eye on the excellent Pharyngula website. A simple, but thoughtful approach to a possible replicating process leading to life as we understand it was recently posted on Pharyngula::

http://www.youtube.com/watch?v=U6QYDdgP9eg

Other Comments by aheggie

39. Comment #194181 by Alfrescoid on June 16, 2008 at 2:00 pm

If millions of years of continent-sized lava flows in the Permian could not destroy life, and if an asteroid collision with a force of millions of nuclear weapons at the end of the Cretaceous could not do it, then we can't.

Agreed. But as Sagan so succinctly put it, we are unique as a species in one fundamental way - the ability to wipe ourselves (and a good portion of our cousin species) out.

Oh, life would arise again (and again), but wouldn't it be a shame if the cosmic observer aboard Sagan's spaceship would have to wait several hundreds of millions of years for the next technological society to arrive before watching them achieve the possibility of interstellar travel?

Wouldn't he think it such a tragedy to know the humans nearly made it, and probably would have if they could have stopped bickering with each other long enough?

Other Comments by Alfrescoid

40. Comment #194183 by moderndaythomas on June 16, 2008 at 2:05 pm

but wouldn't it be a shame if the cosmic observer aboard Sagan's spaceship would have to wait several hundreds of millions of years for the next technological society to arrive before watching them achieve the possibility of interstellar travel?

That's assuming it's inevitable. I think the jury's still out on this one.

In fact, now that this thread is almost all Sagan, I recall his analogy to life in the universe liken to a Christmas tree with its lights flashing individually.
One light on here and then it's out then another on there and then that one's out, etc.

Other Comments by moderndaythomas

41. Comment #194187 by HourglassMemory on June 16, 2008 at 2:10 pm

Imagine those planets each developed their own intelligent species.
You'd have Star Wars!

Other Comments by HourglassMemory

42. Comment #194205 by Koreman on June 16, 2008 at 2:27 pm

@Comment #194013 by mesomodel on June 16, 2008 at 9:30 am

Not quite. Planets in rapid orbits are close to their host star. Tidal locks will be fairly common with such planets, like the moons' spin is locked to its orbit around earth. In respect to the planets detected it's rather safe to say their spins have slowed down.

Other Comments by Koreman

43. Comment #194209 by MelM on June 16, 2008 at 2:28 pm

Don't make travel plans just yet. Wikipedia says:

Link: Super-earth.
A Super-Earth is the popular misnomer for a large extrasolar terrestrial planet. The standard criterion is that it has a least twice the mass of Earth, but less than ten Earth masses.

In the topic "Terrestrial planet", there are links to projects attempting to image the exoplanets.

Link: Terrestrial planets.
A number of telescopes capable of directly imaging extrasolar terrestrial planets are on the drawing board. These include the Terrestrial Planet Finder, Space Interferometry Mission, Darwin, New Worlds Mission, the kepler mission, and Overwhelmingly Large Telescope

Other Comments by MelM

44. Comment #194230 by HitbLade on June 16, 2008 at 2:43 pm

But hey, the vatican already said it's "OK" to believe there are aliens out there :D I guess we go there and determine if they have a soul, or if we just baptize them to be safe before we slaughter them. Worked in the past.

Other Comments by HitbLade

45. Comment #194276 by moderndaythomas on June 16, 2008 at 3:09 pm

MelM .

Right, 9.4 times the mass of Earth would make it rather difficult to get up off my seat and fetch a Keith's....that's beer.

Other Comments by moderndaythomas

46. Comment #194366 by bachfiend on June 16, 2008 at 4:37 pm

The first thing that occurred to me when I read this article was; has anyone actually named these new planets? If not this would be a great money-making exercise, perhaps we could auction the naming rights on eBay? The second thing that occurred to me is that I wouldn't want to move to one of them; the thought that I'd be 967 years old on the one orbiting in 20 days doesn't appeal.

Other Comments by bachfiend

47. Comment #194368 by Drool on June 16, 2008 at 4:40 pm

Newbie question. The article mentions mass, but aren't they just indirectly measuring size and inferring mass - or does size generally correspond to mass for planets of this type?

Other Comments by Drool

48. Comment #194373 by mordacious1 on June 16, 2008 at 4:57 pm

42 light years away, let's see, if we can get Scotty to maintain warp 10 (She canna do it Cuptun), we should be there in...wait what about the Klingons?

Other Comments by mordacious1

49. Comment #194389 by bachfiend on June 16, 2008 at 5:23 pm

Getting back to something serious, the planet Earth, aged 4,000,000,000 years, said in a release published on; http://www.thedailymash.co.uk/news/environment/i'll-be-just-fine,-says-planet-20080306774/
that it isn't worried about global warming.

Other Comments by bachfiend

50. Comment #194400 by Rational_G on June 16, 2008 at 5:40 pm

Close in planets are faster to detect (faster orbital periods) and easier to detect (greater doppler shift) using the wobble method.

So we have discovered more of these type. The technique is getting better which is why we can detect smaller "super earth size" now as opposed to "gas giant size'' as in Jupiter size, Neptune size etc.

Pretty exciting.

A different method for finding exoplanets is the planetary transit method. The ESA Corot spacecraft uses this method and has found two Jupiter size exoplanets and possibly a smaller one.

See

http://www.esa.int/SPECIALS/COROT/SEMF0C2MDAF_0.html

http://www.esa.int/SPECIALS/COROT/SEM9E91YUFF_0.html

No word on whether Jesus has saved these places yet............

Other Comments by Rational_G