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Is it possible to run off the planet?

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If an object is moving parallel to the ground at ground level, neither rising nor falling, is it possible that it could still leave the planet if moving fast enough?

Not factoring in aerodynamics or air friction, just toying with the concept of a ground "speed limit", beyond which a super speedster (absent a power that keeps them earthbound) will simply go rocketing off into space.

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Yeah, there's this simple concept called "escape velocity". I recommend googling it.

It is not quite that simple. If you running, when do you "take off" and how fast would you need to be going to maintain enough speed to escape earth's gravity.

 

I can see running up a hill and getting to the top and going from there. It would all depend on the height of the hill I suspect...

 

Doc

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I included the relevant calculations on my rookie Flash build in the downloads section.

 

From: https://forum.rpg.net/showthread.php?795840-HERO6E-My-rookie-JLA-builds&p=20707008#post20707008

 

0 8) Orbital Speed Running: Flight 16m, No Turn Mode (+1/4), Reduced Endurance (0 END; +1/2), MegaScale (1m = 1 km; +1), Noncombat Acceleration/Deceleration (+1) (60 Active Points); Only In Contact With A Surface (This Limitation is primarily due to his Psychological Limitation: Fear of Flying. Flash believes that he can't properly fly without spinning arms or something similar. Reduce active points down to 50 without this Limitation; -1/4) Real Cost: 40

[Notes: Top Speed (with current Advantages) = 18,000mph ( ~ Mach 24) or 8km/s (kilometers per second). Velocity Based DCV = 17. Orbital speed at Sea Level = 7.90973km/s (This means that IF he were to lose contact with the surface while AT or ABOVE this speed he will NOT fall due to Gravity since he's traveling at ESCAPE VELOCITY!)] - END=0

 

0 9) Speed Force Running: Flight 10m, No Turn Mode (+1/4), Combat Acceleration/Deceleration (+1/4), Reduced Endurance (0 END; +1/2), Noncombat Acceleration/Deceleration (+1), Usable Simultaneously (up to 2 people at once; +1), Grantor can take back power at any time, Recipient must be within Limited Range of the Grantor for power to be granted, MegaScale (1m = 10,000 km; +2) (60 Active Points); Only In Contact With A Surface (This Limitation is primarily due to his Psychological Limitation: Fear of Flying. Flash believes that he can't properly fly without spinning arms or something similar. Reduce active points down to 50 without this Limitation; -1/4) Real Cost: 40

[Notes: Top Speed (with current Advantages) = 111,846,814 mph or 50,000km/s (kilometers per second) or ~ 1/6th the speed of light (approximately 300,000 km/s, or 186,000 miles per second). From (http://dcanimated.wikia.com/wiki/Divided_We_Fall) his globe circling attack versus Braniac/Luthor 1st Run: 10 seconds @4,000 km/second, 2nd Run: 9 seconds @4,444 km/s, 3rd Run: 11 seconds @3,636 km/s, 4th Run: 5 seconds @8,000 km/s and final 5th Run: 1 second @40,000 km/s] - END=0

 

 

HM

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Yes, but at what velocity and air resistance compensation, I have no idea.  I would guess if you bought FTL for 10 points defined as running, you could do it rather easily. :)

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On a side note, at full escape velocity(around 11km per second), a character reaches the "horizon line"(the furthest point they could see the ground ahead of them) in about half a second.  The horizon line is due to the curvature of the planet.  So, one way of looking at it is that at a high enough speed, it kinda is like running off a "ramp".  Not really but it's a fun image.  :)

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Yes. It's more a case of "How does a super speedster running at such speeds manage to not go into space?". The comic book physics of their special effect may well answer that question, however. For example, if their "speed" is caused by temporal effects and they *actually* run normally form their own perspective, it's more of a pseudo speed and they'll stay on the ground. 

 

(You do realise that this is a velocity of around 40,000 kph?)

 

The horizon radius isn't relevant here. That's calculated from the viewpoint of your eyes and the tangent between that point and the earth's surface What you can actually see at the horizon line depends on the height of the objects that lie past it - that's just a matter of geometry.

 

The contact point between your foot and the ground is effectively already a tangent point (zero distance) and has no horizon. The dropoff happens immediately, though even on a perfect sphere the size of the earth this would be insignificant between one step and another. Essentially every step forward you drop a tiny amount ( and your vertical axis rotates a tiny bit forward) as well.

 

The dropoff for a kilometre of horizontal distance is roughly 78.5mm, but it's an exponential, not a linear relationship. 10km puts you 7.85 metres high, 100km puts you around 785 m high and travelling sideways 1000km puts you 78km up, which is effectively outside the atmosphere.

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In summary:

 

1.     The escape velocity for Earth is 11.2 km per second.  This is how fast you need to go to get out of the gravity well.

2.     7.9 km/s is the orbital velocity at 1m. Going faster than that will not get you out of the gravity well, it will get you a higher orbit, at least until you reach escape velocity.

3.     It will make a difference which direction you are running, because the planet is rotating.

4.     Rockets don’t start off at escape velocity, they accelerate up a long way to where the escape velocity is much lower.  Just saying.

5.     This is Hero, so we sort of assume that you are protected from the natural consequences of our powers.  If we can shoot lasers from our eyes, we assume that our eyes don’t fry.  If we are running, we assume you stay on the surface you are running on.  Assuming that there are ‘natural physics’ consequences to Hero powers, will lead to trouble.  Some idiot is going to say they can grab someone, accelerate them to escape velocity then chuck them off the planet.  Hmm.  I think not.

6.     If you are using natural physics consequences, you really can not ignore air resistance, and other forces.  If you were travelling at escape velocity at sea level you would ignite from air resistance.  The air would slow you down and you don’t have any way to maintain your velocity once you leave the surface because you are running.

7.     If you really, really have to do this, it is a power trick, and will only work once.

8.     If you have a flight speed of 1m/s you can get out of the gravity well, eventually.

9.     If you have bought running, you can not use it as leaping or flying, without the appropriate build so, technically, it does not matter if you can theoretically run at lightspeed, you would still not leave the surface you are running on.

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I watched on You Tube an episode of ‘60s Flash and that is how they got him to leave earth. The villain ran so fast that he couldn’t stop (Or he couldn’t change direction apparently) and he ran right up a ramp and back into space.

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I've been in cars moving so fast that they start to lift off the pavement, which let me clue you is not a very comfortable sensation.  I don't think a runner would have that problem mostly because their wind resistance is not going under them so much as ramming around them.

 

In Hero terms, of course, the power "running" does not allow you to fly or leave the ground, so it doesn't matter how fast you go.

 

Personally I've never liked the concept of putting real world limitations and physics on a game which inherently violates physics and logic to begin with.  If you can believe someone can run 11,000 mph, let alone breathe at that speed, then its completely reasonable they could stay on the ground comfortably as well.

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