First Sign Of Water Found On An Alien World

New Scientist ^ | 4-10-2007 | David Shiga

[blam]

First sign of water found on an alien world

22:07 10 April 2007
NewScientist.com news service
David Shiga

Water has been detected in the atmosphere of an alien world for the first time, a new analysis of Hubble Space Telescope data suggests. Water was widely believed to exist on the planet, but previous observations with other telescopes had failed to find it.

The planet, called HD 209458b, is about 70% as massive as Jupiter and is scorched by the heat of its parent star, which it orbits 9 times as close as Mercury does to the Sun.

Because it is one of a small number of extrasolar planets observed to pass directly in front of and behind their parent stars as seen from Earth, astronomers have been able to glean a lot of information – such as its size and mass – about the distant world.

In February, researchers using the infrared-sensitive Spitzer Space Telescope announced that there was no sign of water vapour in its atmosphere. Since the molecule is expected to be abundant in the atmospheres of extrasolar planets, some speculated that the water signal was obscured by a dusty haze.

Now, Hubble observations seem to have revealed the missing water. Travis Barman of Lowell Observatory in Flagstaff, Arizona, US, did a computer analysis of previously obtained Hubble data taken when the planet partially eclipsed its parent star.

Filtered starlight

The amount of light blocked during these eclipses was previously used to precisely determine the planet's radius, which is about 30% greater than that of Jupiter.

Hubble observed light from the host star that had filtered through the outer reaches of the planet's atmosphere. Because of its specific chemical composition, the atmosphere is more transparent at some wavelengths than others.

[kinoxi]

I always take these extrasolar measurements with a grain of salt.

[RightWhale]

Water would not be uncommon. If they find one with oxygen as well, look out!

[adorno]

Water would not be uncommon. If they find one with oxygen as well, look out!

The big news will be when they discover a planet with a lot of CO2. Then we can ship Al Gore and John Kerry to do battle with the governments there to stop their global warming.

[RightWhale]

There’s one within spitting distance. Venus is some day going to be extremely valuable real estate.

[Pietro]

"HD 209458b, is about 70% as massive as Jupiter"

"...determine the planet's radius, which is about 30% greater than that of Jupiter.

So what's it going to be Horace?

[Alter Kaker]

So what's it going to be Horace?

What's your point? There's no contradiction between those two statements.

[Tzimisce]

Interesting.

[Tzimisce]

Interesting.

[Glenn]

So what's it going to be Horace?

Mass and Size are two different animals. Just ask my auntie Hortense.

[Enchante]

"is scorched by the heat of its parent star, which it orbits 9 times as close as Mercury does to the Sun"

Therefore, I hope that human-emitted CO2 will not be considered the cause of excessive heating on this planet...

[Chode]

i know i went to public skool, but...
The planet, called HD 209458b, is about 70% as massive as Jupiter and is scorched by the heat of its parent star, which it orbits 9 times as close as Mercury does to the Sun.

...previously used to precisely determine the planet's radius, which is about 30% greater than that of Jupiter.

ok... so which is it???

and nine times closer than Mercury as compared to what? it's already closest to the sun.

[calex59]

Anyone who can look up at the night sky and believe we are the only planet with life need to have their head examined.

[Alter Kaker]

ok... so which is it???

The planet is less massive than Jupiter, but physically larger. The two are not the same measurement. Just like a bowling ball is more massive and yet smaller than a beach ball.

and nine times closer than Mercury as compared to what?

That's just poor writing. Its orbit is 1/9th as far out as Mercury's -- in other words, it's extremely close to its star.

[SuzyQue]

You’re scaring me. It is denser than Jupiter, and therefore has a smaller diameter, and it is not in our solar system.

[hobblemaster]

I blame Global Warming

[TommyDale]

I hear they also discovered several cases of Scotch.

[chaos_5]

"HD 209458b, is about 70% as massive as Jupiter"

"...determine the planet's radius, which is about 30% greater than that of Jupiter.

So what's it going to be Horace?

You seem to be confusing some definitions. I hope this will clear things up for you.

 

Mass - Abbr. m Physics A property of matter equal to the measure of an object's resistance to changes in either the speed or direction of its motion. The mass of an object is not dependent on gravity and therefore is different from but proportional to its weight

 

http://dictionary.reference.com/browse/mass

 

Radius - A straight line extending from the center of a circle or sphere to the circumference or surface:

 

http://dictionary.reference.com/browse/radius

 

See, what they are saying is, if you put the two planets on a scale Jupiter would be heavier, but HD 209458b would be bigger.

[Recon Dad]

The planet, called HD 209458b

I will name this world “Tanning World” much better than the above.

[Chode]

thx...