Position of two stars relative to eachother

GTE

Hello,

I was looking out at the stars a few weeks back and if I stood with the moon ahead of me and looked around 90 degrees to the right I'd see two stars, one much brighter than the other.

A few weeks ago they looked as if they were two corners of a box (top left and bottom right for example)

Now they are nearly in line with eachother if we take a line perpendicular to the earth.

What's making them move like this?
I thought stars didn't move this dramatically.

Thanks
Bbk

paulosham

God is making them move like that.



But seriously, you are more than likely looking at Venus and Jupiter.

GTE

paulosham wrote: »

God is making them move like that.



But seriously, you are more than likely looking at Venus and Jupiter.

Ahh, now that would make a lot of sense!

Thanks!

Edit:

Quick question coming out of this, im guessing at one point they could be on opposite sides of the sky depending on how their orbits are at any one time?
Edit2: not so much opposite sides of the sky but I imagine they are quite as close to eachother as they can be, what's the craic when they are at their furthest is where I'm coming from.

If so, how long would it take for them to line up back to the way they are today?

Ill go do a google search now but I thought I'd ask people who know what they are on about aswell :-)

paulosham

They were in conjunction on the 15th of March and the next time will be in late May of next year. Venus will transit Jupiter in 2065 but I probably won't be around for that. Not sure when they are in opposition. You should download Stelarium, it's free http://www.stellarium.org/

gkell2

bbk wrote: »

Ahh, now that would make a lot of sense!

Thanks!

Edit:

Quick question coming out of this, im guessing at one point they could be on opposite sides of the sky depending on how their orbits are at any one time?
Edit2: not so much opposite sides of the sky but I imagine they are quite as close to eachother as they can be, what's the craic when they are at their furthest is where I'm coming from.

If so, how long would it take for them to line up back to the way they are today?

Ill go do a google search now but I thought I'd ask people who know what they are on about aswell :-)

Try this -

http://math-ed.com/Resources/GIS/Geometry_In_Space/java1/Temp/TLVisPOrbit.html

If you think of cars on a circuit,you are looking at Venus basically swerving around the Sun at its widest point and getting bigger and brighter as it catches up to us, in June it will overtake us -

http://www.masil-astro-imaging.com/SWI/UV%20montage%20flat.jpg

Unlike the planets moving in outer circuits,Venus has 'phases' which add to the spectacle in showing the planet getting brighter as it comes closer to us so that by June the half that faces the Sun will be bright and the other half that faces us will be completely dark as it whizzes by our slower moving planet as we watch it move in an inner orbital circuit -

http://www.youtube.com/watch?v=mTqT5pk9vTM


Galileo did more than most to popularize the telescope and use the observations effectively yet he still took time out to praise Copernicus for noting why Venus dims and brightens as it makes a circuit around the Sun and I hope Galileo's observation will answer your question in that Venus will eventually become less bright as the gap between it and the glare of the Sun diminishes until it is lost in the light of the central Sun -

"SALV.But the telescope plainly shows us its horns to be as bounded and
distinct as those of the moon, and they are seen to belong to a very
large circle, in a ratio almost forty times as great as the same disc
when it is beyond the sun, toward the end of its morning appearances. "

SAGR. 0 Nicholas Copernicus, what a pleasure it would have been for
you to see this part of your system confirmed by so clear an
experiment [telescope]!

SALV. Yes, but how much less would his sublime intellect be celebrated
among the learned! "
Galileo ,Dialogue Concerning the Two Chief World Systems, 1632

As Venus lags behind the Sun it is now the 'evening star' but when it overtakes us with the central Sun as a backdrop in June it precedes the dawn and becomes the 'morning star' as older people knew it.

GTE

paulosham wrote: »

They were in conjunction on the 15th of March and the next time will be in late May of next year. Venus will transit Jupiter in 2065 but I probably won't be around for that. Not sure when they are in opposition. You should download Stelarium, it's free http://www.stellarium.org/

Thanks for that. I looked up conjunction and basically it means that they will be close to eachother or at least in the same night sky? It happens regularly enough I suppose.

Interesting stuff.

Thanks all!

gkell2

bbk wrote: »

Thanks for that. I looked up conjunction and basically it means that they will be close to eachother or at least in the same night sky? It happens regularly enough I suppose.

Interesting stuff.

Thanks all!

Well,to be fair to the great astronomers,even those in antiquity,conjunctions were much more than this and the great triple conjunction in 1504 would have been seen by Copernicus as it is basically a line of sight event where planets overtake each other or the Earth overtakes these planets.

In 1504,observers would have seen the faster Mars overtake the slower moving and further Saturn and Jupiter only to stop and move in the opposite direction back past Jupiter and Saturn,stop and then overtake them once again,the latter effect being that the moving Earth is overtaking Mars and causes it to appear to move backwards.Within 10 years Copernicus had worked out that the Earth is turning daily and the loop-the-loop retrograde motion is an illusion due to the orbital motion of the Earth.The further the planet the less its apparent backward motion such as seen in the nearer Mars and the further Uranus but observers should have a good idea of these things by now -

http://apod.nasa.gov/apod/ap031216.html

It is nice to see that even with all the modern distractions that men here have taken the time out to inquire what is going on presently as the motions of Venus and Earth move the slower moving Jupiter from left to right of Venus in our respective orbital circuits and that is what conjunctions really represent.