Monday, April 30, 2007

The Exo Life wager - as it stands April 30th 2007.

Wager 1.

When will we observe the first Earth-like planet (Earth twin)
outside our own solar system?
--That is, a planet of roughly the same size, in the habitable zone around its star,
with an atmosphere, suitable for terraforming and eventually human settlements. --

See previous posts for details -
As of April 24th 07 - It almost looks like Jan has already won
this wager.
Certainly, If the Exo Earth around Gliese 581 is rocky,
has an atmosphere and is suitable for human settlement
- this in is a win for Jan!

But we need confirmation on the atmosphere and its rocky'ness. And
we need furher information on whether its 2G gravity pull is within the
definition of a "twin Earth".
All of this will probably be settled in the coming years -
but sofar wager 1 looks like a win for Jan.

Wager 2.

When will we discover the first certain signs of life outside Earth?
--A measurement on an exoplanets atmosphere that indicates life,
a fossil on Mars, bacteria in deep space or something else that
proves life outside the ecosphere of Earth.

Jan Holst Jensen:
Uncertain about detection of fossils and bacteria. But bets on
discovery of an exoplanet, with an atmosphere that indicates the
presence of life before 2020.

Simon Laub:
Bets on discovery of a fossil or a living bacteria (like structure)
or life structures (something that has the "feel" of life)
to be discovered inside our solar system and outside Earth -
within the next 50 years. I.e. before 2057.

And exoplanet with an atmosphere that indicates the presence of life
follows from one of the many interesting missions, such as Kepler, that will
be launched in the next decade. So Simon bets on discovery of an exo planet
with life before 2017.

Wager 3.

When will we have the first signal from exo life?
-- Direct observation of exo life.
A SETI signal, or a spacecraft that observes exo life
(fossils, bacteria), or a signal (a roar or likewise) from exo life,
or footprints or .. in short - when will we have direct signs of (exo) life.

Jan Holst Jensen:
Before 2050 we will have observed an exo planet with highlevel animals comparable
to vertebrates.

Simon Laub:
Thinks there will be a discovery of some kind of extraterrestrial life
within the solar system within the next 50 years. Probably very primitive
though. Direct discovery of life outside the solar system will take new technologies
in rocket design. And apparently rockettechnologies aren't proceeding that fast.
So the bet here is as bad as a 100 - 150 years from now - which is really just to say in some very distant future.

The hope rest on SETI signals.
We will have a SETI signal within the next 50 years. So, before 2057 we will have
our signal from exo life.

Wager 4.

When will we have our first signal from intelligent exo life?
I.e. exo life complex enough to
be on par with some of the intelligent species we have here on Earth.

Jan Holst Jensen:
Will be observed before 5060 - or never :-)

Simon Laub:
Obviously, the Fermi paradox still reigns - and could leave one
believing that we will never find intelligent extraterrestrtial life -

However, it just takes one brilliant new theory on how signals
are sent accross deep space to suddenly have a whole new approach.
So with advances in signal capabilities and general physics knowledge we
will come to explore whole new ways of communicating. Eventually, we
will tumble on a SETI signal- And it will happen before

revised April 30th 2007.

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Tuesday, April 24, 2007

Gliese 581 exo planet - WAUV - a major step towards a new Earth

In a find­ing that if con­firmed could stand as a land­mark in history, as­tro­no­mers have re­ported dis­co­v­er­ing the most Earth-like plan­et out­side our So­lar Sys­tem to date: a world that may have liq­uid oceans and thus life......

Located only 20.5 light-years away - Gliese 581 is among the 100 closest stars. So close, that we could consider sending a mission towards Gliese within this century!


Lets recapitulate what this blog is all about: A wager on when we will find the first true exo Earth.

We had talked about this for years before 2002 - but 5 years ago we formalized the bet to: When will we find Earth 2? And this blog was initialized - I.e.:

[The planet we are talking about must not only look like Earth in size and color - we think it must have an atmosphere,
perhaps even a diverse landscape where life can find many different
niche's. In some distant future it should be possible for
humans to settle the place. It short, it should be VERY Earthlike.
Obviously, all other kinds of planets will also be extremely
interesting, but here we are talking about Earth II. ]

It was further understood that the Exo Earth should be within the habitable zone of its star. Gravity should be Earth like - We didn't have to many details on what the atmosphere should be like - but the planet should have an atmosphere - and it should potentially be possible to terraform that atmosphere in order for people to be able to settle the planet. The planet should also have a "home" feeling - i.e. look like Earth- where it almost follows from this that there should be liquid water on the planet (but again, we left if for the the future to settle the exact details).

And we had:
Jan Holst Jensen: - The Kepler Mission will find such a planet more or less immediately after launch. That is in 2007 - 2008.

Simon Laub: Was a little bit more cautious, ..So he is betting on 2012.

The interesting date is the confirmation date. But we are ok with a little wiggle-room for a debate on whether we should instead be talking discovery date. Discovery date is allowed - if the discovery
has all the hallmarks of a confirmation as well.


Fast forward to April 24th 2007...

Gliese's planet is in the habitable zone of the Star!
The red dwarf Gliese 581, is smaller and colder than the Sun – and thus less luminous – the planet lies in the habitable zone, the region around a star where water could be liquid!

Glies's planets gravity would be twice that of Earth.
Which then makes it open to interpretation, whether that is something humans could settle. But for now it seems ok.

Moreover, the planet around Gliese's radius is estimated to only 1.5 times the Earth’s radius, and models predict that the planet should be either rocky – like our Earth – or covered with oceans,” he said.

Obviously, we need confirmation on all of this. But so far this is very promising.

With water and an atmosphere on Gliesse's Earth like planet - a nice blue feel to it - Jan is the winner of our wager.
Long before the Kepler mission even made it to liftoff...

But we need more details. The wager is not settled yet!


The Gliese story so far - April 24th 2007:


In a find­ing that if con­firmed could stand as a land­mark in history, as­tro­no­mers have re­ported dis­co­v­er­ing the most Earth-like plan­et out­side our So­lar Sys­tem to date: a world that may have liq­uid oceans and thus life.

Swiss, French and Por­tu­guese sci­en­tists found the body, es­ti­mated as 50 per­cent wid­er than our Earth, or­bit­ing a so-called red dwarf star rel­a­tively close to Earth. The star is thought to har­bor two oth­er plan­ets al­so.

The new­found exo­pla­n­et—as as­tro­no­mers call plan­ets around stars oth­er than the Sun—would be the small­est such body ev­er re­ported.

None­the­less, the object is es­ti­mat­ed to weigh as much as five Earths, part­ly thanks to its great­er width. For the same rea­son, it would have more than twice Earth’s sur­face ar­ea. His­tor­i­cally, only large exo­pla­n­ets lend them­selves to hu­man de­tect­ion, though that is chang­ing.

Oth­er cu­ri­ous fea­tures of the new­found plan­et are that grav­i­ty at its sur­face would be around twice as strong as on Earth; and its year is just 13 Earth days long, as it comp­letes one or­bit about its sun in that time.

It’s 14 times clos­er to its star than we are from our Sun, re­search­ers said. But since its host star, the red dwarf Gliese 581, is smaller and cool­er than the Sun, the plan­et nev­ertheless would lie in its hab­it­a­ble zone—the re­gion around a star with suit­a­ble tem­pe­r­a­tures for liq­uid wa­ter.

Av­er­age tem­pe­r­a­tures on this “supe­r-Earth” lie be­tween 0 and 40 de­grees Cel­si­us (32 to 104 de­grees Fahren­heit), “and wa­ter would thus be liq­uid,” said Sté­phane Udry of Switz­er­land’s Ge­ne­va Ob­serv­a­to­ry, lead au­thor of a pa­pe­r re­port­ing the re­sult. “Mod­els pre­dict that the plan­et should be ei­ther rock­y—like our Earth—or cov­ered with oceans,” he added.

Liq­uid wa­ter is crit­i­cal to life as we know it,” not­ed Xa­vi­er Delfosse, a mem­ber of the team from Gre­no­ble Uni­ver­si­ty, France.

“Be­cause of its tem­pe­r­a­ture and rel­a­tive prox­im­i­ty, this plan­et will most prob­a­bly be a very im­por­tant tar­get of the fu­ture space mis­sions ded­i­cat­ed to the search for extra-terrestrial life. On the treas­ure map of the Uni­verse, one would be tempted to mark this plan­et with an X.”

The host star, Gliese 581, is among the 100 clos­est stars to us, ly­ing 20.5 light-years away in the con­stel­la­tion Li­bra (“the Scales.”) A light-year is the dis­tance light trav­els in a year.

Gliese 581 has one third the mass of our Sun. Such small stars, called red dwarfs, are at least 50 times faint­er than the Sun and are be­lieved to be the most com­mon stars in our gal­axy. Among the 100 clos­est stars to the Sun, 80 be­long to this class.

“Red dwarfs are ide­al tar­gets for the search for such plan­ets be­cause they emit less light, and the hab­it­a­ble zone is thus much clos­er to them than it is around the Sun,” said Xa­vi­er Bon­fils, a co-re­searcher from Lis­bon Uni­ver­si­ty. Plan­ets near a star are eas­i­er to de­tect be­cause their grav­i­ta­tion­al pull af­fects the par­ent star no­tice­ably, in­duc­ing some­thing of a wig­gling mo­tion.

Red dwarfs are al­so ex­pected to live ex­traor­di­nar­ily long be­cause they burn fu­el slow­ly. A red dwarf one-third the Sun’s mass, like Gliese 581, would typ­i­cal­ly shine for some 130 bil­lion years, out­liv­ing the Sun by thir­teen times. That might re­lieve at least one source of stress for any in­hab­i­tants of a red dwarf sys­tem. We on Earth are al­ready half­way through the Sun’s life­time, though much time re­mains.

Two years ago, Udry and his team found anoth­er plan­et around Gliese 581, es­ti­mat­ed to weigh as much as 15 Earths—about as much as Nep­tune—and or­bit­ing the star in 5.4 days.

At the time, the as­tro­no­mers had al­ready not­ed hints of anoth­er plan­et, Udry and col­leagues said. They thus took new mea­sure­ments and found the new “supe­r-Earth,” as well as a like­ly third plan­et weigh­ing eight Earths and or­bit­ing in 84 days. The find­ings have been sub­mit­ted to the re­search jour­nal As­tron­o­my and As­t­ro­phys­ics, the sci­en­tists said.

The find was pos­si­ble thanks to an in­stru­ment known as a spec­tro­graph on the Eu­ro­pe­an South­ern Ob­serv­a­to­ry’s 3.6-meter tel­e­scope at La Silla, Chil­e, ac­cord­ing to the group. The in­s­tru­ment, called the High Ac­cu­ra­cy Ra­di­al Ve­loc­i­ty for Plan­e­tary Search­er, is touted as one of the most suc­cess­ful tools for de­tecting exo­pla­n­ets to date.

The in­stru­ment meas­ured wig­gles in the star’s mo­tion cor­re­spond­ing to ve­loc­i­ty changes of just two to three me­ters per sec­ond—the speed of a brisk walk, ac­cord­ing to the Ge­ne­va Ob­serv­a­to­ry’s Mi­chel May­or, prin­ci­pal in­ves­ti­ga­tor for the in­stru­ment. Giv­en the re­sults so far, “Earth-mass plan­ets around red dwarfs are with­in reach” of dis­cov­ery, he pre­dicted.


An international team of astronomers from Switzerland, France and Portugal have discovered the most Earth-like planet outside our Solar System to date.

The planet has a radius only 50 percent larger than Earth and is very likely to contain liquid water on its surface.

The research team used the European Southern Observatory’s (ESO’s) 3.6-m telescope to discover the super-Earth, which has a mass about five times that of the Earth and orbits a red dwarf already known to harbour a Neptune-mass planet.

Astronomers believe there is a strong possibility in the presence of a third planet with a mass about eight times that of the Earth in the system.

However, unlike our Earth, this planet takes only 13 days to complete one orbit round its star. It is also 14 times closer to its star than the Earth is from the Sun.

However, since its host star, the red dwarf Gliese 581, is smaller and colder than the Sun – and thus less luminous – the planet lies in the habitable zone, the region around a star where water could be liquid!

“We have estimated that the mean temperature of this super-Earth lies between 0 and 40 degrees Celsius, and water would thus be liquid,” said Stéphane Udry from the Geneva Observatory, Switzerland and lead-author of the paper in the journal Astronomy and Astrophysics.

“Moreover, its radius should be only 1.5 times the Earth’s radius, and models predict that the planet should be either rocky – like our Earth – or covered with oceans,” he said.

“Liquid water is critical to life as we know it and because of its temperature and relative proximity, this planet will most probably be a very important target of the future space missions dedicated to the search for extra-terrestrial life. On the treasure map of the Universe, one would be tempted to mark this planet with an X,” added Xavier Delfosse, a member of the team from Grenoble University, France.

According to the research team, the host star, Gliese 581, is among the 100 closest stars to us, located only 20.5 light-years away in the constellation Libra (“the Scales”).

The star has a mass only one third that of the Sun. Such red dwarfs are at least 50 times intrinsically fainter than the Sun and are the most common stars in our Galaxy. Among the 100 closest stars to the Sun, 80 belong to this class.

“Red dwarfs are ideal targets for the search for such planets because they emit less light, and the habitable zone is thus much closer to them than it is around the Sun. Any planets that lie in this zone are more easily detected with the radial-velocity method, the most successful in detecting exoplanets,” said Xavier Bonfils, a co-worker from Lisbon University.

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Wednesday, April 18, 2007

Getting closer - exo planet with water

We are getting closer to that Exo Earth ... all the time.

Astronomers have detected water in the atmosphere of a planet outside our solar system for the first time.

The finding, to be detailed in an upcoming issue of Astrophysical Journal, confirms previous theories that say water vapor should be present in the atmospheres of nearly all the known extrasolar planets. Even hot Jupiters, gaseous planets that orbit closer to their stars than Mercury to our Sun, are thought to have water.

The discovery, announced today, means one of the most crucial elements for life as we know it can exist around planets orbiting other stars.

“We know that water vapor exists in the atmospheres of one extrasolar planet and there is good reason to believe that other extrasolar planets contain water vapor,” said Travis Barman, an astronomer at the Lowell Observatory in Arizona who made the discovery.

HD209458b is a world well-known among planet hunters. In 1999, it became the first planet to be directly observed around a normal star outside our solar system and, a few years later, was the first exoplanet confirmed to have oxygen and carbon in its atmosphere.

HD209458b is separated from its star by only about 4 million miles (7 million kilometers)—about 100 times closer than Jupiter is to our sun—and is so hot scientists think about it is losing about 10,000 tons of material every second as vented gas.

"Water actually survives over a broad range of temperatures," Barman explained. "It would need to get quite a bit hotter to completely break the water molecules apart."

Using a combination of previously published Hubble Space Telescope measurements and new theoretical models, Barman found strong evidence for water absorption in the atmosphere of the extrasolar planet HD209458b.

Barman took advantage of the fact that HD209458b is a so-called “transiting planet,” meaning it passes directly in front of its star as seen from Earth. It transits every three-and-a-half days.

When this happens, water vapor in the planet’s atmosphere causes the planet to appear slightly larger in the infrared part of the starlight than in the visible portion.

Barman found the water signature after applying new theoretical models he developed to visible and infrared Hubble data collected by Harvard student Heather Knutson last year, which measured the perceived size of the planet over a broad range of wavelengths.


Other scientist wonder why many exo planets don't have
water - wondering whether they have been to Earth centric.....

Scientists taking their first "sniffs of air" from planets outside our solar system are baffled by what they didn't find: water.

One of the more basic assumptions of astronomy is that the two distant, hot gaseous planets they examined must contain water in their atmospheres. The two suns the planets orbit closely have hydrogen and oxygen, the stable building blocks of water. These planets' atmospheres — examined for the first time using light spectra to determine the air's chemical composition — are supposed to be made up of the same thing, good old H2O.

But when two different teams of astronomers used NASA's Spitzer Space Telescope for this new type of extrasolar planet research, they both came up dry, according to research published in Thursday's edition of Nature and the online version of the Astrophysical Journal Letters.

The study of one planet found hints of fine silicate-particle clouds. Research on the other planet found no chemical fingerprints for any of the molecules scientists were seeking.

Approach too ‘Earth-centric’
"We had expected this tremendous signature of water ... and it wasn't there," said the study leader for one team, Carl Grillmair of the California Institute of Technology and Spitzer Science Center. "The very fact that we've been surprised here is a wake-up call. We obviously need to do some more work."

Grillmair's colleague, Harvard astronomy professor David Charbonneau, said these surprising "sniffs of air from an alien world" tell astronomers not to be so Earth-centric in thinking about other planets.

"These are very different beasts. These are unlike any other planets in the solar system," Charbonneau said. "We're limited by our imagination in thinking about the different avenues that these atmospheres take place in."

Our own solar system has two planets without water in the atmosphere, Grillmair noted: Mercury, which doesn't have an atmosphere, and Venus, which is a different type of planet from the huge gaseous ones that would be expected to have the components of water in the air.

Water may be hiding, scientists suggest
So far, scientists have found 213 planets outside our solar system, but only 14 have orbits that make it possible for this type of study; only eight or nine of those are close enough to see. Grillmair's team studied the closest, which goes by the catchy name HD 189733b. It's a mere 360 trillion miles from Earth in the constellation Vulpecula. The other planet, HD209458b, is about 900 trillion miles away in the constellation Pegasus, and it's the one with the strange silicate cloud.

So where'd the water go?

Maybe it's hiding, scientists suggest. The water could be under dust clouds, or all the airborne water molecules have the same temperature, making it impossible to see using an infrared spectrograph. Or maybe it's just not there and astronomers have to go back to the drawing board when it comes to these alien planets.

The other finding on the more distant of the two planets seems to indicate that the atmosphere is full of silicon-oxygen compounds, said study lead author L. Jeremy Richardson of NASA's Goddard Space Flight Center.

"They'd be like dust grains and they would form clouds," Richardson said. And that cloud of silicates could be blocking the space telescope from measuring lower-lying water, he and other scientists said.

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