# Thread: Would Superman generate a contrail?

1. I've been doing a lot of reading over the past few days trying to figure out what it would be like to have Superman in the real world. The rules are that you suspend one point of disbelieve, which is that Superman would have all these powers. The challenge is understanding how they would behave in the real world.

In this example, if Superman were flying so fast a stationary observer couldn't see him:
1. How fast would that have to be?
2. Would that speed create sufficient friction to generate heat and what would this look like?
3. Would that speed generate a contrail caused by the change in air pressure left in his wake?

This is meant to be a bit of interesting fun but I'd also really appreciate some good intellgent answers!

Thanks,

2.

3. Bons question

4. What effect would that speed have on Superman's immediate surroundings? i.e. a few tables might get blown over, right?

4. How fast do you have to be going before a stationary observer cannot see you?

5. Hi SpeedFreak. After posing the first part of my question (1. How fast would that have to be?), I realised that it would probably be relative according to the distance of the observer from Superman and also probably depend on the angle of his trajectory relative to them.

With that in mind, let's pick some specific average speeds to work with:
a. The muzzle velocity of a rifle bullet: 1.7km/s
b. Re-entry speed of a space shuttle: 7.8km/s
c. Escape velocity from the ground on Earth: 11.2km/s

These are just some really high speeds to use as benchmarks.

6. There shouldn't be any contrail. A contrail is caused by condensation of airplane engine exhaust, and Superman doesn't emit any exhaust. He moves by some unexplained force. There is also sometimes a vapor trail at airplane wing tip vortices, but Superman's lift does not come from wings. Again it's some unexplained force.

7. Thanks, Harold. Couldn't contrails be formed by the change in pressure left in his wake, such as the vapor cone that can occur when a plane breaks the sound barrier in humid conditions?

8. Originally Posted by Harold14370
There shouldn't be any contrail. A contrail is caused by condensation of airplane engine exhaust, and Superman doesn't emit any exhaust. He moves by some unexplained force. There is also sometimes a vapor trail at airplane wing tip vortices, but Superman's lift does not come from wings. Again it's some unexplained force.
Not entirely true. Contrails can be generated by the wakes from wingtips strictly from the pressure differences. I've observed it numerous times when landing in big jets.

9. only if he farted at high altitude

10. Originally Posted by fizzlooney
only if he farted at high altitude
I guess you don't understand atmospheric physics.

11. Originally Posted by MustUsePowers

In this example, if Superman were flying so fast a stationary observer couldn't see him:
1. How fast would that have to be?
2. Would that speed create sufficient friction to generate heat and what would this look like?
3. Would that speed generate a contrail caused by the change in air pressure left in his wake?

This is meant to be a bit of interesting fun but I'd also really appreciate some good intellgent answers!

Thanks,
Do you mean he's flying faster than the speed of light, or that he's flying faster than the frame rate of the human eye allows us to track him?

If he's going faster than light through the air, there's a chance he might emit Cherenkov Radiation, which is a blue light that gets emitted when electrons move faster through a medium than the speed at which light would move through the same medium (not faster than C, though, because C is the speed of light in a vacuum).

If I remember right, Superman sometimes flies to distant galaxies, so he must be able to move faster than C also.... but there's no way to know what that would cause because no object has ever been observed to move faster than C.

12. What's going on here?

No one's ever heard of SUPERFLUIDITY ?