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View Full Version : Does our sun wobble?

Plat
2005-Apr-03, 06:56 AM
If aliens right now were looking at our sun checking for planets and using the wobble method, would our sun wobble? or does it only wobbe when there is a Hot Jupiter with an eccentric orbit?

Crazieman
2005-Apr-03, 07:00 AM
I'm not sure.

I would think Jupiter occultations viewed from a distance could be noticed

Normandy6644
2005-Apr-03, 07:08 AM
It depends on how powerful their instruments are. Right now our current technology allows us to see a 3 m/s velocity shift, and that might be the best possible (I'm not sure on that one though). Jupiter is close enough to the sun (5 AU I think) to induce at least a 3 m/s velocity shift, so I would imagine an alien astronomer would be able to tell that the sun has planets. As least Jupiter, and maybe even Saturn.

A Thousand Pardons
2005-Apr-03, 12:53 PM
Jupiter is close enough to the sun (5 AU I think) to induce at least a 3 m/s velocity shift, so I would imagine an alien astronomer would be able to tell that the sun has planets.
Jupiter is about 777 million km from the Sun, and its period is 11.86 years. So, its velocity is 2*pi*777*10^9 m/11.86*365.25*24*60*60 s, or 13,000 m/s. Since Jupiter is about a thousand times less massive, the velocity induced in the Sun would be about 13 m/s

Normandy6644
2005-Apr-03, 03:54 PM
Jupiter is close enough to the sun (5 AU I think) to induce at least a 3 m/s velocity shift, so I would imagine an alien astronomer would be able to tell that the sun has planets.
Jupiter is about 777 million km from the Sun, and its period is 11.86 years. So, its velocity is 2*pi*777*10^9 m/11.86*365.25*24*60*60 s, or 13,000 m/s. Since Jupiter is about a thousand times less massive, the velocity induced in the Sun would be about 13 m/s

Well there you go, it would be easily detectable with our current technology. Looking around it seems that Saturn is right on the edge, perturbing the sun about 2.8 m/s.

dutche
2005-Apr-06, 09:05 PM
by wobble, do you mean as the earth wobbles? i think this is due to the moon being tidaly locked to the earth. i don;t know if any planets are tidally locked to the sun (but i know mercury is close)

tracer
2005-Apr-07, 01:05 AM
Since Jupiter is about a thousand times less massive, the velocity induced in the Sun would be about 13 m/s

Looking around it seems that Saturn is right on the edge, perturbing the sun about 2.8 m/s.
So, which is it? 13 m/s or 2.8 m/s?

Normandy6644
2005-Apr-07, 02:09 AM
Since Jupiter is about a thousand times less massive, the velocity induced in the Sun would be about 13 m/s

Looking around it seems that Saturn is right on the edge, perturbing the sun about 2.8 m/s.
So, which is it? 13 m/s or 2.8 m/s?

Jupiter is 13, Saturn is 2.8.

dvb
2005-Apr-07, 02:56 AM
by wobble, do you mean as the earth wobbles? i think this is due to the moon being tidaly locked to the earth. i don;t know if any planets are tidally locked to the sun (but i know mercury is close)

Yes, our sun wobbles from the planets pulling on it. :D

Plat
2005-Apr-07, 03:11 AM
I mean if aliens were looking at our sun using the wobble method....but it would take longer to see a wobble from a planet that is further away right?

crosscountry
2005-Apr-07, 03:31 PM
I mean if aliens were looking at our sun using the wobble method....but it would take longer to see a wobble from a planet that is further away right?

yes. it's periodic. Jupiter is further than the earth and thus a slower period.

the planets we've found have very small periods (some as little as 3 days) and are more easily detectible on short scale time frames.

plantes like Jupiter would take at least 1/2 period to find. but use many periods to find others.

saturn would take even longer.

Charlie in Dayton
2005-Apr-08, 05:49 AM
Wobble, no.

Bobble, yes.

...ouch...no more...I'll stop, I promise... [-X

01101001
2005-Aug-23, 05:51 AM
NASA Feature: The Story Before the Story of Extrasolar Planets (http://www.nasa.gov/vision/universe/newworlds/SIM-young-star-study.html)

But with SIM PlanetQuest [Launch 2011], scientists will be able to measure a star's wobble with exquisite precision against a background of stars so distant they appear to be stationary. Using this technique, Beichman's group expects to be able to detect planets of less than one Jupiter mass at distances greater than five times the distance from Earth to the Sun, which is where Jupiter orbits in our own solar system, as well as larger planets closer in.

Donnie B.
2005-Aug-23, 12:35 PM
SIM PlanetQuest... sounds like a good idea for a plug-in for The Sims! 8)