NASA Shows Future Space Telescopes Could Detect Earth Twin

ToSeek · #1 (**permalink**) 12-April-2007, 01:49 AM

JPL Press Release:

Quote:

NASA Shows Future Space Telescopes Could Detect Earth Twin

For the first time ever, NASA researchers have successfully demonstrated in the laboratory that a space telescope rigged with special masks and mirrors could snap a photo of an Earth-like planet orbiting a nearby star. This accomplishment marks a dramatic step forward for missions like the proposed Terrestrial Planet Finder, designed to hunt for an Earth twin that might harbor life.

Trying to image an exoplanet – a planet orbiting a star other than the sun – is a daunting task, because its relatively dim glow is easily overpowered by the intense glare of its much bigger, brighter parent star. The challenge has been compared to looking for a firefly next to a searchlight.

Now, two researchers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have shown that a fairly simple coronagraph – an instrument used to "mask" a star's glare – paired with an adjustable mirror, could enable a space telescope to image a distant planet 10 billion times fainter than its central star.

“Our experiment demonstrates the suppression of glare extremely close to a star, clearing a field dark enough to allow us to see an Earth twin. This is at least a thousand times better than anything demonstrated previously,” said John Trauger, lead author of a paper appearing in the April 12 issue of Nature. This paper describes the system, called the High Contrast Imaging Testbed, and how the technique could be used with a telescope in space to see exoplanets. The lab experiment used a laser as a simulated star, with fainter copies of the star serving as “planets.”

To date, scientists have used various techniques to detect more than 200 exoplanets. Most of these exoplanets are from five to 4,000 times more massive than Earth, and are either too hot, too cold or too much of a giant gas ball to be considered likely habitats for life. So far, no one has managed to capture an image of an exoplanetary system that resembles our own solar system. Scientists are eager to take a closer look at nearby systems, to hunt for and then characterize any Earth-like planets – those with the right size, orbit and other traits considered friendly for life.

In the lab demonstration, the High Contrast and Imaging Testbed overcame two significant hurdles that all telescopes face when trying to image exoplanets – diffracted and scattered light.

When starlight hits the edge of a telescope’s primary mirror, it becomes slightly disturbed, producing a pattern of rings or spikes surrounding the major source of light in the focused image. This diffracted light can completely obscure any planets in the field of view.

To address this problem, Trauger and his colleagues at JPL fashioned a pair of masks for their system. The first, which resembles a blurry barcode, directly blocks most of the starlight, while the second clears away the diffracted rings and spikes. The combination creates enough darkness to allow the light of any planets to shine through.

“Mathematically, and sort of magically, this coronagraph blocks both the central star and its rings,” said Wesley Traub of JPL, co-author of the new paper and Terrestrial Planet Finder project scientist.

Scattered light presents the additional hurdle. Minor ripples on a telescope’s mirror produce “speckles” – faint copies of a star, shifted to the side, which can also hide planets. In the High Contrast Imaging Testbed, a deformable mirror the size of a large coin limits scattered light. With a surface that can be altered ever so slightly by computer-controlled actuators, this mirror compensates for the effects of minor imperfections in the telescope and instrument.

“This result is important because it points the way to building a space telescope with the ability to detect and characterize Earth-like planets around nearby stars,” Traub said.

For their next steps, Trauger and Traub plan to improve the suppression of speckles by a factor of 10, and extend the method to accommodate many wavelengths of light simultaneously.

More information on NASA's planet-finding missions, including Terrestrial Planet Finder, is at http://planetquest.jpl.nasa.gov .

JPL manages the Terrestrial Planet Finder mission for NASA's Science Mission Directorate, Washington. JPL is a division of the California Institute of Technology in Pasadena.

3rdvogon · #2 (**permalink**) 12-April-2007, 03:24 PM

This is interesting stuff.

Does this mean we might not have to wait until the end of this century before it becomes possible to launch a telescope capable of imaging an earthlike exoplanet. That will surely allow us to at least start putting some meaningful numbers into the Drake equation.

GaryFenza · #3 (**permalink**) 12-April-2007, 11:30 PM

nice, might be another earth out there with "life" just like our planet. To bad i probably wont be alive by then to see it

NEOWatcher · #4 (**permalink**) 13-April-2007, 12:40 PM

Quote:

Originally Posted by 3rdvogon

Does this mean we might not have to wait until the end of this century before it becomes possible to launch a telescope capable of imaging an earthlike exoplanet. That will surely allow us to at least start putting some meaningful numbers into the Drake equation.

I don't think the telescope is able to tell us whether it is a twin of Earth, but will be able to find them if they exist, and maybe tell if the density and chemistry is similar.

I am assuming that right now we can only tell exoplanet mass, and have a hard time separating the spectroscopy.

But yes, being able to "visually" seperate a planet from it's sun is exciting.

Trantor · #5 (**permalink**) 13-April-2007, 03:12 PM

This is very exciting news. I just hope this gets the funding that it deserves. I would really like to know what is out there, in terms of Earth-sized planets located in proper orbits around some of our stellar neighbors. I've always wanted to know about our nearest neighbor, the Alpha Centauri system; we know that there are no really big planets there, but there is plenty of room for smaller Earth-sized planets. Hopefully, we will be able to analyze the gases that make up the atmospheres of target planets, this should give a good indication of probable life.

In my opinion, this project should have at least as high a priority as the manned spaced program. Let's put some real effort into knowing more about our place in the Universe.

FTL_Diesel · #6 (**permalink**) 13-April-2007, 03:45 PM

Quote:

Originally Posted by NEOWatcher

I don't think the telescope is able to tell us whether it is a twin of Earth, but will be able to find them if they exist, and maybe tell if the density and chemistry is similar.

I am assuming that right now we can only tell exoplanet mass, and have a hard time separating the spectroscopy.

But yes, being able to "visually" seperate a planet from it's sun is exciting.

If you can collect photons from the planet ("visually separate" it), you can do spectroscopy.

NEOWatcher · #7 (**permalink**) 13-April-2007, 04:19 PM

Quote:

Originally Posted by FTL_Diesel

If you can collect photons from the planet ("visually separate" it), you can do spectroscopy.

Yep, I worded that funny...I meant that without this technology you can't seperate it.

Van Rijn · #8 (**permalink**) 14-April-2007, 06:58 AM

Quote:

Originally Posted by 3rdvogon

This is interesting stuff.

Does this mean we might not have to wait until the end of this century before it becomes possible to launch a telescope capable of imaging an earthlike exoplanet. That will surely allow us to at least start putting some meaningful numbers into the Drake equation.

I expect we will be seeing quite a few earth sized exoplanets in the next two or three decades.

Amber Robot · #9 (**permalink**) 17-April-2007, 03:22 PM

Quote:

Originally Posted by FTL_Diesel

If you can collect photons from the planet ("visually separate" it), you can do spectroscopy.

Depends on how faint it is. And what spectral resolving power you want to get.

LurchGS · #10 (**permalink**) 18-April-2007, 05:28 AM

ToSeek - you scared me there.. I had visions of that *Awful* movie / tv series "Earth 2" (I think it was - too lazy to look it up) - about the alternate earth on the other side of the sun - everything identical except the natural charge on things.. or something like that.

You shouldn't do that to an old man.

Kullat Nunu · #11 (**permalink**) 19-April-2007, 12:08 AM

Well, it can't be the '90s Earth 2 series as it doesn't occur on the "counter-Earth".

EDIT: Maybe this one?

Van Rijn · #12 (**permalink**) 19-April-2007, 12:51 AM

Quote:

Originally Posted by Kullat Nunu

Well, it can't be the '90s Earth 2 series as it doesn't occur on the "counter-Earth".

EDIT: Maybe this one?

Or perhaps this:

http://en.wikipedia.org/wiki/The_Str...281973_film%29

which was a series pilot, but it didn't get sufficient interest.

There are two Earth IIs - the '90s series (where people go to another solar system) and the 1971 made for TV movie:

http://www.imdb.com/title/tt0067039/

about life on an earth orbiting space station (I thought it was done pretty well, given budget limits), not to be confused with the Roddenberry pilot movie, Genesis II.

cosmo-julie · #13 (**permalink**) 01-May-2007, 08:28 PM

its ludicrous but fun - we're running a challenge to name earths twin

surely you can do better than "581c" ?

Amber Robot · #14 (**permalink**) 02-May-2007, 03:29 PM

Quote:

Originally Posted by cosmo-julie

its ludicrous but fun - we're running a challenge to name earths twin

Isn't it a bit hyperbolic to use the word "twin"? The planet is at least 5 times as massive as the Earth and we have no idea what kind of surface/atmosphere it might have. Certainly Venus and Mars are both much closer to being "Earth's Twin" than this planet.

NEOWatcher · #15 (**permalink**) 02-May-2007, 04:57 PM

Quote:

Originally Posted by Amber Robot

Isn't it a bit hyperbolic to use the word "twin"? The planet is at least 5 times as massive as the Earth and we have no idea what kind of surface/atmosphere it might have. Certainly Venus and Mars are both much closer to being "Earth's Twin" than this planet.

Kallut's link was the first one that I heard this particular find refered to as a twin. Since it's a blog, I tend ignore it. I believe this thread adds to the confusion by saying there is technology to find A twin.

Media is (generally) refering to the newly found planet as a super Earth.
This thread is refering to technology that would be able to find a twin Earth.

Besides, what criteria is used to determine twin-ality? At what boundry is a twin not a twin?

01101001 · #16 (**permalink**) 11-January-2008, 06:39 PM

Thread revival

AAS News

Same folks from OP propose a different platform for their method:

NewScientist (purveyors of some facts, some hype): Balloon-borne telescope could image exoplanets

Quote:

A balloon-borne telescope afloat in the stratosphere could offer a direct view of planets in other solar systems, says a team of researchers. If successful, the lofty scheme would deliver images of alien worlds impossible to see from the ground – and all for a fraction of what it would cost to do the job from space.
"It's one of those ideas that actually has a remote chance of making it off the drawing board," says team leader Wes Traub, a senior research scientist at NASA's Jet Propulsion Lab in Pasadena, California, US.
[...]
"We'll be seeking funding for a balloon-borne coronagraph this year," said Traub, who presented his results this week at the American Astronomical Society meeting in Austin, Texas. "If we come up with a good design, maybe we'll have a chance at this."
The proposal drew interest from astronomers – along with some reservations about whether a balloon-borne telescope could be controlled with enough precision to tease out the elusive images of exoplanets.
Traub estimates the project, dubbed "Planetscope", would cost $10 million dollars, roughly 1% the cost of a space-based planet imager.

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