I just came across this really fun page. What would happen to our solar system if another star came hurtling through it? Well, this page will show you. Give it a try. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

http://janus.astro.umd.edu/orbits/rstar.html

Try these inputs to see something really funny:

Start date: Jan. 01, 1990
Show outer planets
Star's mass: .5
Closest distance: 5 AU
Speed: Average

Have fun. And hope it never happens in real life.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

Tennis Anyone?

Too Bad it Only Shows The Inner, or The Outer Planets, but Not at Same Time; Now That would be Interesting.

The Term, DEEP Doo-Doo, Definitely comes To Mind!

__________________
If you Ignore YOUR Rights, they Will go away.

WOW! What a fun site.

If only I could achieve those kind of bank shots when I play billiards!


(:raig

Great Site, David.

Has anyone been able to get the Earth to become a satellite of the Rogue Star? I've been able to pawn off Venus, but not the Earth. [img]/phpBB/images/smiles/icon_smile.gif[/img]

I ran it twice, using David's suggested starting conditions, once at Average and once at Below Average speed, and got different results. That doesn't bother me, of course, I would more or less expect that--except that in the first run, we had Uranus literally bouncing off the Sun! Ran right up to it and bounced as clearly as you could ask.

I somehow suspect that that wouldn't actually happen that way! [img]/phpBB/images/smiles/icon_razz.gif[/img]

Anyway, certainly a great site!

The (I wonder if it's available as a screen-saver) Curtmudgeon

Get rid of all those pesky outer planets; show Jupiter whose its daddy!

2/01/01 Start
Outer Planets
.4 Solar Masses
2.3 AU closest
Above Average Speed

__________________
But I, remembering, pitied well
And loved them, who, with lonely light,
In empty infinite spaces dwell,
Disconsolate. For, all the night,
I heard the thin gnat-voices cry,
Star to faint star, across the sky.

—— Rupert Brooke,

That's entertaining. [img]/phpBB/images/smiles/icon_wink.gif[/img] I think the parameters of the program's representation of "solar masses" vs. "speed" on entering and leaving the solar system is more aesthetic rather than scientific. (i.e. perhaps not really based on real data for our sun, planets, and a proposed star.) But its still fun.

In one version, I had Mercury collide with Venus while the Earth and Mars shared near orbital positions for a year. Then things settled down for Earth and Mars in new orbits.

In another version, (an 8 mass rouge star entering fast at 1 AU,) the whole solar system flew apart, but while rapidly leaving the the area, the sun recaptured the earth with earth's orbit appearing to again be at about the same "93 million mile" distance from the sun! The new sun-earth system then exited the screen at high speed to who knows where! That would be a wild ride. [img]/phpBB/images/smiles/icon_eek.gif[/img]

<font size=-1>[ This Message was edited by: Chip on 2002-07-19 20:14 ]</font>

Great!

But years ago I had a share-ware program for my Mac that did things like this, only better. I can't run it on this PC and I'd love to find a Windows version. I appeal to anybody; do you know of any simple (free or cheap! ) celestial mechanics programs out there that can let you set up your own system with whatever masses and orbital parameters you choose? I need one as a teaching tool, soon! Any leads appreciated!

I tried it with average speed, .5 solar masses and a distance of 1 AU. Earth was history. I then tried it with 5 AU. Earth faired OK but Mars was quite perturbed.

I ran it again with the same parameters to see what happened to the outer planets. All of them except Saturn got kicked out of the system. Saturn ended up in a highly eliptical orbit.

Very cool site.

I did [img]/phpBB/images/smiles/icon_smile.gif[/img] Really close orbit though...

02-01-2001, 9 masses(!) closest approach 1 AU, Very slow speed...

Actually it was an accident I meant to put in .9 masses... [img]/phpBB/images/smiles/icon_razz.gif[/img]

__________________
"Ignorance has caused more calamity than malignity" H.G. Wells

"Getting lost is part of exploring." Uniqua in "Backyardigans-Heart of the Jungle"

"Trying to wrap my head around creationist astronomy is like trying to ride a unicycle around a Moebius strip: it’s off-balance, physically impossible, full of one-sided arguments, and in the end you don’t go anywhere." Phil Plait

I ran 1 Solar mass at 1A.U., very fast starting January 2003 through the inner system. Clears the field!!!!!!

What gives??? I run it about 6 times with different parameters and then it won't work any more?

...found another one, probably better:

http://www.tillnow.com/solar/

I ran your numbers and the 9 mass object comes back to the sun again dragging the Earth, Venus and Mercury along. Mercury and Venus get ejected during the second close pass to the sun. The Earth might get picked up again by the 9 mass object, but the time runs out and they move off screen. Darn. [img]/phpBB/images/smiles/icon_smile.gif[/img] The orbits of the three planets make a neat pattern.

Kizarvexis

I can do you one that is better. Use these numbers.

02/01/2001
Inner
.1 Solar Masses
.1 AU
Above Avg Speed

Kizarvexis
P.S. Then change the speed to average to get a close up view of Mars and Mercury. [img]/phpBB/images/smiles/icon_smile.gif[/img]

PPS. Just try all the speeds with .1 mass and .1 AU. You get some really weird and dangerous orbits.


<font size=-1>[ This Message was edited by: Kizarvexis on 2002-07-20 07:04 ]</font>

<font size=-1>[ This Message was edited by: Kizarvexis on 2002-07-20 07:06 ]</font>

I've been playing. [img]/phpBB/images/smiles/icon_smile.gif[/img]

I'm tired of orbiting clockwise around the sun and getting a tan takes too long. Try this.

02/01/2001
Inner
.1 mass
.2 AU
Above Avg Speed

Kizarvexis

Well I'm glad everybody liked my find. It sure is fun to see what kind of havoc you can inflict upon our system isn't it.

Now, I'm sure the simulation uses real physics, but it's also true that it doesn't take every possible influence into account. For one thing, it's only 2-dimensional and the rogue star must come in along the ecliptical plane. Also, I noticed that if you have a simulation that sends an outer planet into the inner solar system, and then run the same simulation on the inner system, that outer planet doesn't appear, which would probably alter things quite a bit.

Now as for the "bouncing Uranus" example I gave above, I was shocked to see it too, which is why I gave that example. My guess is that it's not really bouncing, but just circling the Sun at such a tight perihelion that the scale can't show it, so it looks like a bounce. The same could be said of any simulation where two planets seem to collide.

There also seems to be a bug in the system. I can't get any simulation to appear where the star is exactly 1 solar mass. The server is also appallingly slow to connect sometimes. Maybe it sometimes takes a lot of time to process the inputs.

So, while it can't be said to be a completely accurate simulation, it sure shows you what kind of effects there would be in such an encounter. And judging from all the possible times I've put in, it looks like most of them would be unpleasant (to understate it terribly).

Finally, thanks to roidspop for the system simulator program. I'm going to give it a try.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

Started having another play with the rogue star program, anyone enjoy playing keepy-uppy with mercury??

Try this:

Default date
inner planets
0.5 solar mass
1 AU
Very slow

I found some problems. The Sun is never affected, no matter how massive the rogue star. Setting a 10 Sun mass rogue star, at 5 AU, the rogue star was captured by the Sun.

Seems to be a general problem with most simulations in that you like to use the sun as a reference point and therefore have it's position stated as a constant. Hopefully someone will be brave and program the sun to move around as well. Might try it myself at some point, then I can play around with binary system sims....

I don't think that's a problem. The simulation is given with the Sun as the reference frame, so naturally it stands still. It's not that it isn't affected, just that the "camera" is always centered on it.

In a different frame of reference you'd be seeing the Sun orbiting the rogue star.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

I think it is a problem. In the case I described, the star performed a perfectly elliptical orbit around the Sun, when they should revolve around a common CG. Then, even if the Sun was a fixed reference, the orbital pattern of the rogue star wouldn´t be that fashion. An astronomy newby would be confused.

Predictably they couldn´t cope with the 3 bodies problem.

But i´m not willing to disrepute the simulation, which is very nice indeed.

I think it would be nice if you could view the sim using a point in space as the reference point, although this runs the risk of losing all the objects off the edge of the creen during one of the more spectacular flybys, but hey, that's why we like that program!!

A-ha!

I’d been looking for that one. Thanks a lot, David.

Well know i get it why they call it eh ROGUE star because it caused such a SCANDAL!!!!!!!!!!!

With the following parameters:

Date: 4/28/03
Inner Planets
.5 Solar Masses
.9 Au
Average Speed


Mercury gets carried off and orbits the rogue star!

__________________
"Is that a laser pointer? Well...that's fantastic! I mean...wow..that's just...GREAT!"
-Donald Rumsfeld before a Nov. 2001 speech
(His enthusiasm was muted, however, when he learned he could not guide a bomb with it.)

A question:
The site does not seem to have any parameters to account for the position of the rogue star when it enters the solar system. Just the shortest distance to the Sun. Surely, the effect on the orbits also depends on the direction from which the rogue star approaches the planets!
Still a cool simulation, anyway.

Jupiter as a ping pong ball?
2/01/2001
Outer Planets
6 Solar Masses
6 AU
Average Speed

All of the outer planets scatter except Jupiter, which keeps pinging off the Sun!

__________________
"Is that a laser pointer? Well...that's fantastic! I mean...wow..that's just...GREAT!"
-Donald Rumsfeld before a Nov. 2001 speech
(His enthusiasm was muted, however, when he learned he could not guide a bomb with it.)

Mercury didn't like those other planets, anyways.

Date: 5/15/2003
Inner planets
2 Solar Masses
.1 AU
Slow

PANDEMONIUM!!!!!!!

4/28/4003
Outer Planets
100 Solar Masses
20 AU
Average Speed



WHOA!!!!!!!!!!

__________________
"Is that a laser pointer? Well...that's fantastic! I mean...wow..that's just...GREAT!"
-Donald Rumsfeld before a Nov. 2001 speech
(His enthusiasm was muted, however, when he learned he could not guide a bomb with it.)