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View Full Version : Detection of ExtraSolar Planets through Sun's Wobble



jaeger
2005-Apr-01, 11:36 PM
The article on GQ Lupi has me wondering. Would a civilization on a planet 10 to 50 light years away with technology roughly equivalent to current Earth technology be able to surmise that planets orbit the Sun because of gravitational wobble? Or are Jupiter and Saturn not large enough to cause a noticeable wobble?

sol_g2v
2005-Apr-02, 01:41 AM
Since we can detect planets less massive than Saturn with our current level of technology than others at the same level should be able to do the same, provided they observe for a sufficient length of time.

Romanus
2005-Apr-02, 02:19 AM
We could easily detect Jupiter, and Saturn if we were willing to wait long enough. Uranus and Neptune would be theoretically detectable via astrometry, but that would take a long, long time as you can imagine.

Tacitus
2005-Apr-02, 03:07 AM
The article on GQ Lupi has me wondering. Would a civilization on a planet 10 to 50 light years away with technology roughly equivalent to current Earth technology be able to surmise that planets orbit the Sun because of gravitational wobble? Or are Jupiter and Saturn not large enough to cause a noticeable wobble?

Yes, all the gas giants would be detectable over a long enough period.

If by "roughly equivalent", you mean give or take 100 years (which is not much in the grand scheme of things) then they could also probably deduce the presence of the rocky planets of Mars, Earth, and Venus.

But I think that other, more direct detection techniques will eclipse (no pun intended) the "wobble" method - at least for nearby stars - within the next decade or two, so if the equivalent technology aliens are out there, they are probably observing our little planet through hi-tech space telescopes as we write.

nutant gene 71
2005-Apr-02, 03:46 AM
The article on GQ Lupi has me wondering. Would a civilization on a planet 10 to 50 light years away with technology roughly equivalent to current Earth technology be able to surmise that planets orbit the Sun because of gravitational wobble? Or are Jupiter and Saturn not large enough to cause a noticeable wobble?
Here's the link to First Confirmed Picture of a Planet (http://www.space.com/scienceastronomy/050401_first_extrasolarplanet_pic.html). It appears to be about 3 times the distance of Neptune from our Sun, and at 2000K has enough luminosity to be visible. The orbit is 1200 years, about the time of Charlemagne's reign to now, so hard to catch its wobble, since just discovered. At that high temp, might it be more like an odd star. A cool protostar or hot protoplanet? What would happen if Jupiter or Saturn suddenly ignited? I wonder if the explosion would send it flying out to 100 AU orbit, like the GQ Lupi protoplanet? It sure would leave a mess for the rest of us. #-o

TravisM
2005-Apr-02, 05:29 PM
Well, they wouldn't ignite. If they did, magically, then no. They wouldn't move either. They're spherical. Where's the directional thrust needed.
And, yes, it is thought to be a warm protoplanet. 1 to 2 times jupiter mass...