What are rogue planets?

[Admin]

Discover the strange world of rogue planets left to wander the cosmos untethered to any star.

What are rogue planets? : Read more

 

[Unclear Engineer]

They be where the space pirates base their marauding space ships - Argh!

Seriously, if there really are 20 such planets per star in the Milky Way. what are the odds that one will get close enough to Earth that we will notice it inside the solar system?

I would expect that has happened in the last 4.6 billion years.

Hopefully, the odds are extremely low that such a planet will come sailing into our solar system on a trajectory that comes anywhere near Earth, or any other planet. It would not have to actually physically hit Earth to have a drastic effect. A "gravitational collision", where the planets interact gravitationally without physically touching, could still disrupt Earth's orbit enough to destroy habitability.

And there is no way we are going to be able to deflect an incoming object with a mass anywhere near the mass of the Earth, or even the mass of the Moon.

 

[Wolfshadw]

A "gravitational collision", where the planets interact gravitationally without physically touching, could still disrupt Earth's orbit enough to destroy habitability.

I don't think a rogue planet would even need to get that close to cause problems on a planetary scale. Just get close enough to the Oort cloud and generate a new heavy bombardment on the inner solar system. Problem solved!

-Wolf sends

 

[Unclear Engineer]

I doubt that a planet the size of Earth going through the Oort Cloud would produce a "heavy bombardment". We would probably get some comets - over about a thousand years. But, not a calculation, just my SWAG.

 

[Philly]

I have always felt that if humanity and life is to ever leave our sun, in a million years this is how it will travel to another star. Take the whole planet and all the life on it. Of course the tech in a million years most likely will allow us to do this. Much easier than a space ship. If it takes 3 million years to get to the next star system so be it.

 

[Wolfshadw]

I have always felt that if humanity and life is to ever leave our sun, in a million years this is how it will travel to another star. Take the whole planet and all the life on it. Of course the tech in a million years most likely will allow us to do this. Much easier than a space ship. If it takes 3 million years to get to the next star system so be it.

If, in a million (or billion) years, we had the technology to maintain life on Earth without the Sun, why would we need to travel to a new star system?

-Wolf sends

 

[Classical Motion]

We might survive going rouge temp wise. M field keeps atmosphere and we have lots a recyclable super heated water to warm and moisten the air.

But what are we gonna use for light. We need light to power the herb.

And if we don't take the moon with us, our surface will be reground. Continuously I bet..

 

[Helio]

I doubt that a planet the size of Earth going through the Oort Cloud would produce a "heavy bombardment". We would probably get some comets - over about a thousand years. But, not a calculation, just my SWAG.

Yes, and I vaguely recall reading about the limited effects that would come from an unwanted intruder passing through the Oort Cloud.

As for the collision probability question, IMO, given that there are about 20k Apollo NEO asteroids -- the ones that cross our orbit -- without impacting us... much... it seems likely the probability would be extra unlikely of a rogue causing havoc.

 

[Unclear Engineer]

I agree that the likelihood of a rogue planet hitting us, or even getting close, seems really tiny.

But, comparing it to the Apollo asteroids is not really similar enough. The Apollo asteroids are tiny in mass compared to something Earth's size or larger. If something even the mass of Mars came within the Moon's orbit, we would have a "gravitational collision" that would seriously affect Earth's future habitability due to orbit changes.

 

[COLGeek]

Just for grins:

The Wandering Earth - Wikipedia

en.wikipedia.org

 

[billslugg]

I like the part where the Earth was saved from destruction.

 

[Helio]

I agree that the likelihood of a rogue planet hitting us, or even getting close, seems really tiny.

Yes, their cross-sections are much smaller. Thus, if 20,000 Earth-sized objects were also Apollo objects, then missions to Mars becomes far more relevant.

But, comparing it to the Apollo asteroids is not really similar enough. The Apollo asteroids are tiny in mass compared to something Earth's size or larger. If something even the mass of Mars came within the Moon's orbit, we would have a "gravitational collision" that would seriously affect Earth's future habitability due to orbit changes.

Yes, but the point is to compare ~ 23,000 asteroids (Apollo & Aten) crossing Earth's orbit, as well as, staying within a few million miles of that orbit, with that of a few rogue planets many trillions of miles away from Earth's orbit.

I would guess someone has actually done the probability of such an impact.

 

[Helio]

Just for grins:

The Wandering Earth - Wikipedia

en.wikipedia.org

What a hoot! Thanks, that looks like fun, even with the Swiss cheese level of plot holes.

 

[Unclear Engineer]

At this point in our discovery process, I don't think we have a very good idea of how many of what size bodies are out there, untethered to another star. And, it is not clear that we know where the closest one is, now, or where that one is headed.

Perhaps we will get some better data soon, part of it in the search for "planet 9" of our own solar system. But, at this point, if we can't show that planet 9 doesn't exist, we also can't show that there isn't a rogue planet closing in on us at this very moment (if you assume a trillion miles out is "closing in" just because its trajectory will eventually get it here).

 

[Helio]

At this point in our discovery process, I don't think we have a very good idea of how many of what size bodies are out there, untethered to another star. And, it is not clear that we know where the closest one is, now, or where that one is headed.

Perhaps we will get some better data soon, part of it in the search for "planet 9" of our own solar system. But, at this point, if we can't show that planet 9 doesn't exist, we also can't show that there isn't a rogue planet closing in on us at this very moment (if you assume a trillion miles out is "closing in" just because its trajectory will eventually get it here).

Yes. The newer and better IR survey scopes have the potential to find more rogues. But only the larger ones. So, perhaps there are IMFs (Initial Mass Functions) for planetary formation, which might produce the multiplier needed for each large rogue.