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Spider-Man

Banned

From: Pennsylvania

Registered: 2003-08-20

Posts: 163

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Re: Extrasolar Planetary Systems - Could we detect the small planets?

Many scientists today, including Dr. Zubrin, advance the notion that stars with planets are the rule, and no longer the exception.  I certainly believe this, and it makes a lot of sense.

The only planets we are able to detect (so far with little more than just their gravitational Doppler effect on their parent star) have been gas giants, due to their enormous masses which pull on the stars they revolve around.  Any little rocky bodies (like Earth) would not be observable (indeed, keep in mind how hard it is to see Neptune or Uranus, even with a telescope, or even how long it took to discover the asteroid belt, even though we were looking through it almost every time we tried to see Jupiter or Saturn).

Planets being the rule of stars, I thought, "Why then doesn't the Alpha Centauri system have planets?"

It doesn't have gas giants, of course, or their effect would have been known to us long ago.  Truly, the role of the large gas giants themselves is replaced by the small star Proxima Centauri, a pool for the congregation of excess hydrogen and helium.
Nevertheless, all stellar nebulae should theoretically contain plenty of carbonaceous and metallic material to form rocky planets, like the ones of our inner Solar sytem.  All the hydrogen in a stellar nebula has less inertia than heavier elements like iron and other minerals, and so it is pulled to the center most rapidly, forming a star, or stars as with the Alpha Centauri system.  Any leftover rocky material would doubtlessly coalece, and form planets.

This means that stars as close as our neighbors Alpha Centauri A, B, and Proxima Centauri might very well harbor any number of rocky, Earth-sized planets, planets which could harbor water, or even life!  What we've dreamed of could be right next door, and might have been there under our noses all the time!

I believe that in the future we should strongly consider an unmanned interstellar probe like the Orion that would travel to Alpha Centauri, perhaps releasing smaller probes, some that would orbit Centauri A, others for B, and maybe one for Proxima, whilst the other subprobes could break off and examine the extent of the system and take pictures and search for planets.
It would be quite a project, but just imagine the potential finds!

May we find extraterrestrial forms of life in our neighboring stellar system, within our own, and beyond!

Shaun Barrett

Member

From: Cairns, Queensland, Australia

Registered: 2001-12-28

Posts: 2,843

Re: Extrasolar Planetary Systems - Could we detect the small planets?

It was once thought that binary stars didn't have planets because of gravitational instability. Apparently, we now know they do.
    I'm not sure, though, with a more complicated gravitational dance such as occurs in the Centauri system. There seems no reason to doubt that Alpha and Beta Centauri as a binary pair could host an array of planets, even though they are quite a distance from each other, but would adding in a distant Proxima Centauri cause subtle perturbations leading to fatal instability of planetary orbits?

    I have no idea myself but maybe that's why nobody is looking for planets in that system (?).
                                          ???

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The word 'aerobics' came about when the gym instructors got together and said: If we're going to charge $10 an hour, we can't call it Jumping Up and Down.   - Rita Rudner

space_psibrain

Member

Registered: 2002-02-15

Posts: 83

Re: Extrasolar Planetary Systems - Could we detect the small planets?

Of course, that brings up the whole nuclear power in space debate, but sending off probes would be a sound idea.

As for the Centauri System, I believe the dance of the 3 stars does make it more unstable than would be suitable for planetary formation, but perhaps not. Some even say that the sun might have a distant, dark companion....

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"What you don't realize about peace, is that is cannot be achieved by yielding to an enemy. Rather, peace is something that must be fought for, and if it is necessary for a war to be fought to preserve the peace, then I would more than willingly give my life for the cause of peace."

BoBo

Member

Registered: 2003-11-02

Posts: 5

Re: Extrasolar Planetary Systems - Could we detect the small planets?

There are multiple technologies and missions currently under planning and development to detect Earth like planets around nearby stars. Here are some examples:

NGST (Next Generation Space telescope)
http://ngst.gsfc.nasa.gov/FAQ/

Kepler Space Telescope
http://planetquest.jpl.nasa.gov/Kepler/ … index.html

SIM (Space Interferometry Mission)
http://planetquest.jpl.nasa.gov/SIM/sim_facts.html

TPF (Terrestrial Planet Finder) 
http://planetquest.jpl.nasa.gov/TPF/tpf_facts.html

and many more...
Here is a much bigger list (not all links are working within though):
http://www.spacetoday.org/DeepSpa....ns.html

BoBo

Member

Registered: 2003-11-02

Posts: 5

Re: Extrasolar Planetary Systems - Could we detect the small planets?

Here is another really fresh one, almost working... 
We will have to wait 2 more years for it to be fully operational but I think this is the one with the potential of the earliest results in regards of extra Solar system planets (10 times better than the Hubble ST).

http://www.spacedaily.com/news/telescopes-03zr.html

Gennaro

Member

From: Eta Cassiopeiae (no, Sweden re

Registered: 2003-03-25

Posts: 591

Re: Extrasolar Planetary Systems - Could we detect the small planets?

Indeed, I find it highly plausible that the Alpha Centauri system might harbour a number of rocky planets, maybe even gas giants. Only because we haven't spotted them yet doesn't mean they aren't there.
That a binary star system comparable to Alpha Centauri A and B's proximity can hold stable planetary orbits has already been proven :

Check out the Gamma Cephei system:

http://www.extrasolar.net/star.asp?StarID=196

http://www.space.com/scienceastronomy/b … 21009.html

Little Proxima is so enourmously far away from the main pair (several thousand AU's) that I don't think it has any noticable effect on planetary orbits or formation.

Orion probe? Well certainly you mean a fusion craft? An Orion ship at 2 percent light speed (1 percent/light exhaust velocity) would still take 215 years to reach Alpha Centauri.

Anyway, why not take a while to look at this map and contemplate how extremely fortunate we are to have the next yellow star system (constituting about 3 percent of the galaxy population) just next door:

http://www.anzwers.org/free/universe/20lys.html

All about Alpha Centauri:

http://www.solstation.com/stars/alp-cent3.htm

Josh Cryer

Moderator

Registered: 2001-09-29

Posts: 3,830

Re: Extrasolar Planetary Systems - Could we detect the small planets?

Hey, check out Celestia guys. It in includes many stars with probably plantary orbits! I didn't find this out until just recently (I've known about Celestia, I just didn't know it had extrasolar orbits pinned down!). It's pretty awesome.

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Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.

Mars_B4_Moon

Member

Registered: 2006-03-23

Posts: 9,294

Re: Extrasolar Planetary Systems - Could we detect the small planets?

an old topic on the limits of what can be seen

Finding Atmospheres on Red Dwarf Planets Will Take Hundreds of Hours of Webb Time

https://www.universetoday.com/166245/fi … webb-time/