[physics] Aerobraking-ception

[SpaceSphereOfDeath]

What would happen if a, say a Titan like body passed close to the earth, not 'lithobraking' close, but so their atmospheres touch.

What do you think would happen, would they both slowdown due to drag, or somthing else?

[drakesdoom]

The smaller body would be ripped apart by gravity gradient and scattered into a short term ring as it bombards the larger body over the next few thousand years.

[Dkmdlb]

Sounds like a good weekend to me....

[Mr Shifty]

http://en.wikipedia.org/wiki/Roche_limit

[magnemoe]

However it was an 10-30 meter asteroid who passed trough the atmosphere and missed.

This is however pretty unlikely as the atmosphere is very thin compared with earths diameter.

The aerobrake layer between where you don't just lose 1-2 Km/s or reenter is far thinner. In KSP its just a few km in even on Jool. And if the astroid managed an aerobrake orbit the next Pe would be too deep unless Pe was lifted. In shot much more unlikely than an gravity capture.

Now for someting masive like an dinosaur killer or larger the atmosphere would be an minor force as the mass is so large.

[PakledHostage]

There have been a couple of documented cases of Earth grazing asteroids that passed through our atmosphere without impacting or being captured. I recall first reading about the real-life Great Daylight Fireball in Arthur C. Clarke's The Hammer of God. It seems that it passed within 57 km of the surface at 14 km/s and lost 800 m/s during its 100 second encounter with our atmosphere. The great daylight fireball did not appear to break up, but the asteroid that caused the meteor procession of 1860 did.

[Arbolus]

Something the size of Titan wouldn't break up in the short time that it's within Earth's Roche limit, though there would be plenty of huge earthquakes on both bodies and some loose rocks would be exchanged. And I don't think it would be slowed significantly, because only a small fraction of its surface would ever be in contact with Earth's atmosphere.

However, one thing that is likely to happen is that the Earth would tear away quite a lot of Titan's atmosphere. How much of the gas is captured and how much escapes depends on many factors, but if enough is captured it would be comparable in mass to our own atmosphere and might end up asphyxiating us all.