When Will We Be Able to Spot Planets with Oxygen?

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mra...@willamette.edu

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Sep 12, 2006, 7:43:16 PM9/12/06
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Earth is the only planet we've discovered so far with oxygen because as
far as we know, the only way Oxygen can appear in a planets atmosphere
is as a bi-product of life.

Now, we've discovered other planets around other stars, but our
technology is really only at the point where we can see gas giants. But
if we develop our telescopes more, presumably we will eventually be
able to find other Earth-sized planets, as these are probably pretty
common.

http://www.universetoday.com/2006/09/08/earth-sized-planets-are-probably-common/


My question is, around what year do you think we will have developed
our telescopes enough to tell if those Earth-sized planets do or do not
contain oxygen?

--
Mike Ralls

James Nicoll

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Sep 12, 2006, 10:26:44 PM9/12/06
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In article <1158104596....@i3g2000cwc.googlegroups.com>,

<mra...@willamette.edu> wrote:
>Earth is the only planet we've discovered so far with oxygen because as
>far as we know, the only way Oxygen can appear in a planets atmosphere
>is as a bi-product of life.
>
>Now, we've discovered other planets around other stars, but our
>technology is really only at the point where we can see gas giants.

No. The pulsar planets are small (pulsars lend themselves to
detection) and we can spot smaller planets through microlensing.


--
http://www.cic.gc.ca/english/immigrate/
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll (For all your "The problem with
defending the English language [...]" T-shirt, cup and tote-bag needs)

Jack May

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Sep 12, 2006, 11:24:14 PM9/12/06
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"James Nicoll" <jdni...@panix.com> wrote in message
news:ee7q94$cr2$1...@reader1.panix.com...

> In article <1158104596....@i3g2000cwc.googlegroups.com>,
> <mra...@willamette.edu> wrote:
>>Earth is the only planet we've discovered so far with oxygen because as
>>far as we know, the only way Oxygen can appear in a planets atmosphere
>>is as a bi-product of life.
>>
>>Now, we've discovered other planets around other stars, but our
>>technology is really only at the point where we can see gas giants.
>
> No. The pulsar planets are small (pulsars lend themselves to
> detection) and we can spot smaller planets through microlensing.

What is microlensing?

James Nicoll

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Sep 13, 2006, 10:44:29 AM9/13/06
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In article <z9ednbS4ZZVK5JrY...@comcast.com>,

Jack May <jack...@comcast.net> wrote:
>
>"James Nicoll" <jdni...@panix.com> wrote in message
>news:ee7q94$cr2$1...@reader1.panix.com...
>> In article <1158104596....@i3g2000cwc.googlegroups.com>,
>> <mra...@willamette.edu> wrote:
>>>Earth is the only planet we've discovered so far with oxygen because as
>>>far as we know, the only way Oxygen can appear in a planets atmosphere
>>>is as a bi-product of life.
>>>
>>>Now, we've discovered other planets around other stars, but our
>>>technology is really only at the point where we can see gas giants.
>>
>> No. The pulsar planets are small (pulsars lend themselves to
>> detection) and we can spot smaller planets through microlensing.
>
>What is microlensing?
>
Gravity bends light, right? So any mass can act like a lens
and if a planet gets between us and a star, we can spot the lensing
effect.

The catch is that microlensing requires a particular arrangement
of star, planet and us, one that is unlikely and won't repeat, so you
need to examine a lot of stars to spot even one world this way and you
only get one short period of observation.

Microlensing can work at great distances, as shown by
OGLE-2005-BLG-390Lb, a 5.5 Earth mass planet found orbiting either
a red dwarf or a white dwarf about 21,000 light years from Earth.

William P. Baird

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Sep 13, 2006, 1:23:33 PM9/13/06
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mra...@willamette.edu wrote:

> My question is, around what year do you think we will have developed
> our telescopes enough to tell if those Earth-sized planets do or do not
> contain oxygen?

About five to ten years. Once we have a telescope that can resolve
the planetary disk, we'll be able to get spectrums of what's around it
PDQ.

So call it 2011 to 2016.

Actually, with some thought, we might be able to do it a lot sooner.
As soon as we detect a wobble of the right size, we can check to
see if the spectrum of the star changes accordingly as the planet
transverses the star.

That's instrumentation, a purposeful hunt, and luck then. Not a new
telescope. It might happen tomorrow depending on what the planet
hunters are doing.

Will

> Mike Ralls

--
William P Baird Do you know why the road less traveled by
Home: anzhalyu@gmail. has so few sightseers? Normally, there
Work: wba...@nersc.go is something big, mean, with very sharp
Blog: thedragonstales teeth - and quite the appetite! - waiting
+ com/v/.blogspot.com somewhere along its dark and twisty bends.

Thomas Womack

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Sep 13, 2006, 2:35:53 PM9/13/06
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In article <1158168213.9...@m73g2000cwd.googlegroups.com>,

William P. Baird <anzh...@gmail.com> wrote:
>mra...@willamette.edu wrote:
>
>> My question is, around what year do you think we will have developed
>> our telescopes enough to tell if those Earth-sized planets do or do not
>> contain oxygen?
>
>About five to ten years. Once we have a telescope that can resolve
>the planetary disk, we'll be able to get spectrums of what's around it
>PDQ.

A telescope capable of resolving the disks of Earth-sized planets and
looking for oxygen in the spectrum would be obliged to be above the
atmosphere, and if it's to be working in ten years then silicon
carbide would be being polished and metal bent today. I don't know of
any such project; the first-generation space interferometers might be
able to do detection but not spectroscopy, and they're arbitrarily
delayed thanks to the focus on the Moon enforced on NASA by the
present US administration.

> Actually, with some thought, we might be able to do it a lot sooner.
> As soon as we detect a wobble of the right size, we can check to
> see if the spectrum of the star changes accordingly as the planet
> transverses the star.

That's been done to detect sodium in the atmosphere of close-in
superjovians, using Hubble, and focussing on sodium because it has the
right spectral properties. HD209458b blocks 1.5% of the disc of the
star, has presumably a rather extended atmosphere given its
temperature, and transits every 3.52 days; an Earth-like planet in an
at all plausible orbit would transit much more rarely, block very much
less of the disc of the star, and be I suspect impossible to detect
with current or planned telescopes.

Tom

A.Mo...@nhm.ac.uk

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Sep 13, 2006, 9:02:25 PM9/13/06
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William P. Baird schrieb:

> About five to ten years. Once we have a telescope that can resolve
> the planetary disk, we'll be able to get spectrums of what's around it
> PDQ.
>
> So call it 2011 to 2016.
>

Actually, it is actually possible to resolve a planetary disk - to a
certain degree
(e.g. for Beta Pictoris: Telesco et al.(2005) Nature 433). Even
spectroscopy is possible. However, not yet good enough for planets.

Recently, in a talk one of the planet hunters claimed that they expect
to detect earth sized planets with the current techniques in the time
frame above.

Andreas


--
Andreas Morlok
Department of Earth and Planetary Sciences
Kobe University
Kobe
Japan

Mike Combs

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Sep 14, 2006, 1:28:30 PM9/14/06
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"Thomas Womack" <two...@chiark.greenend.org.uk> wrote in message
news:P3v*Ip...@news.chiark.greenend.org.uk...

>
> A telescope capable of resolving the disks of Earth-sized planets and
> looking for oxygen in the spectrum would be obliged to be above the
> atmosphere,

I myself wrote a short sf story where I talked about detecting the
"absorption lines of oxygen and water vapor", but I subsequently read
somewhere that where oxygen is concerned, one would be much more likely to
detect the lines for ozone, and then infer the presence of oxygen.

--


Regards,
Mike Combs
----------------------------------------------------------------------
By all that you hold dear on this good Earth
I bid you stand, Men of the West!
Aragorn


Jens Egon Nyborg

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Sep 14, 2006, 3:03:06 PM9/14/06
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Thomas Womack wrote:
> In article <1158168213.9...@m73g2000cwd.googlegroups.com>,
> William P. Baird <anzh...@gmail.com> wrote:
>
>>mra...@willamette.edu wrote:
>>
>>
>>>My question is, around what year do you think we will have developed
>>>our telescopes enough to tell if those Earth-sized planets do or do not
>>>contain oxygen?
>>
>>About five to ten years. Once we have a telescope that can resolve
>>the planetary disk, we'll be able to get spectrums of what's around it
>>PDQ.
>
>
> A telescope capable of resolving the disks of Earth-sized planets and
> looking for oxygen in the spectrum would be obliged to be above the
> atmosphere, and if it's to be working in ten years then silicon
> carbide would be being polished and metal bent today. I don't know of
> any such project; the first-generation space interferometers might be
> able to do detection but not spectroscopy, and they're arbitrarily
> delayed thanks to the focus on the Moon enforced on NASA by the
> present US administration.
>

In Europe we have CoRoT http://exoplanet.eu/corot.html which will pave
the way for Darwin http://www.esa.int/esaSC/120382_index_0_m.html by
findig the planets that Darwin will do spectroscopy on.

Launch for CoRoT is planned to November 15, Darwin not before 2015.

Thomas Womack

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Sep 14, 2006, 7:35:31 PM9/14/06
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In article <eec3fv$49o$1...@home.itg.ti.com>,

Mike Combs <mike...@nospam.com_chg_nospam_2_ti> wrote:
>"Thomas Womack" <two...@chiark.greenend.org.uk> wrote in message
>news:P3v*Ip...@news.chiark.greenend.org.uk...
>>
>> A telescope capable of resolving the disks of Earth-sized planets and
>> looking for oxygen in the spectrum would be obliged to be above the
>> atmosphere,
>
>I myself wrote a short sf story where I talked about detecting the
>"absorption lines of oxygen and water vapor", but I subsequently read
>somewhere that where oxygen is concerned, one would be much more likely to
>detect the lines for ozone, and then infer the presence of oxygen.

The lines for ozone are, tautologically, in that portion of the UV spectrum
absorbed by the ozone layer, so you've got just the same problem trying to
look for it from the ground.

[OK, there's a teeny-tiny line at 602nm, but the optical depths of the
ozone layer on Earth and of the ozone layer you're trying to detect on
an Earth-like planet are going to be confusingly similar in any case]

Tom

Mr Astrolomer

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Oct 24, 2006, 3:18:06 AM10/24/06
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James Nicoll wrote:

> In article <1158104596....@i3g2000cwc.googlegroups.com>,
> <mra...@willamette.edu> wrote:
> >Earth is the only planet we've discovered so far with oxygen because as
> >far as we know, the only way Oxygen can appear in a planets atmosphere
> >is as a bi-product of life.
> >
> >Now, we've discovered other planets around other stars, but our
> >technology is really only at the point where we can see gas giants.
>
> No. The pulsar planets are small (pulsars lend themselves to
> detection) and we can spot smaller planets through microlensing.

via the maldum fornax?

Mr Astrolomer

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Oct 24, 2006, 3:20:45 AM10/24/06
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James Nicoll wrote:

so do you see the star or just infer its existence gravitationally - I would
ask our local Astronomer Royal, "Boomer", but he is busy waiting on protons
to decay so Im asking you ?

Mr Astrolomer

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Oct 24, 2006, 3:26:01 AM10/24/06
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do you want an an answer or a commercial about it ?

Jack May

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Oct 28, 2006, 2:06:16 AM10/28/06
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"Mr Astrolomer" <hu...@hoopah.net> wrote in message
news:453DBECD...@hoopah.net...

>
>
> James Nicoll wrote:
>
>> In article <z9ednbS4ZZVK5JrY...@comcast.com>,
>> Jack May <jack...@comcast.net> wrote:
>> >
>> >"James Nicoll" <jdni...@panix.com> wrote in message

> so do you see the star or just infer its existence gravitationally - I

> would
> ask our local Astronomer Royal, "Boomer", but he is busy waiting on
> protons
> to decay so Im asking you ?

The gravitational field is bending the light so you get an image like you
would get looking through a lens. My guess is that here is probably some
computer processing to correct the distortions of the gravitational lens.


Thomas Womack

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Oct 28, 2006, 4:05:26 AM10/28/06
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In article <453DBECD...@hoopah.net>,
Mr Astrolomer <hu...@hoopah.net> wrote:

>> Microlensing can work at great distances, as shown by
>> OGLE-2005-BLG-390Lb, a 5.5 Earth mass planet found orbiting either
>> a red dwarf or a white dwarf about 21,000 light years from Earth.

>so do you see the star or just infer its existence gravitationally - I would
>ask our local Astronomer Royal, "Boomer", but he is busy waiting on protons
>to decay so Im asking you ?

What you see is that the star behind the star with the planetary
system goes brighter and dimmer in a strange pattern; you then take a
model of the lensing system, and try to fit the pattern of dimmings by
changing the parameters of the model.

If you actually look in that direction, you see the light of the two
stars combined; careful spectroscopy and astrophysical modelling lets
you work out what two kinds of star you've got, the gravitational-lens
work gives you some idea of the mass of the lensing star, and if the
lensing and lensed stars are of obviously different masses you can
tell which is which.

Or you can wait a thousand years for the stars to move far enough
apart to be resolvable by Hubble, but by that point your civilisation
has fallen and you've run out of astrophysics funding.

Tom

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