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Denis12
2006-Mar-23, 10:50 PM
I have tried to jumping as high as i can here on earth near my hometown in the Netherlands on a beach(it was a very clear day) with a hot burning sun ,extreme for the end of March (i am sunburned) but that is normal when you get a whole day on the beach. But i dont know how high you can exactly jump here on earth with 1 G in comparison how high the apollo astronauts have jumped on the moon. I thought it was a good day today to try jumping as high as i can ,but i dont even know how high it is possible with 1 G. I know that the Apollo astronauts has done it with one sixth G. Does anyone know how high you can jump on the earth and on Mars and the other planets? I think that it is interesting stuff for future manned missions to the other planets in our solarsystem. Thanks. Denis12.

Saluki
2006-Mar-23, 11:09 PM
It is not quite as high as you would think. Remember that the Appolo astronauts (and any other astronauts in the forseeable future) are encumbered by quite a bit of equipment, and their motion is restricted by space suits. I am sure others will come in with links, but I recall astronauts talking about trying to jump around and realizing pretty quickly that if they got too carried away they might fall down, which would be fairly dangerous on the Moon.

ToSeek
2006-Mar-23, 11:21 PM
Armstrong jumped (he estimates) about five or six feet but just about lost his balance. Later astronauts were more prudent. See these for various discussions of the issue with respect to the Apollo Moon missions:

http://www.bautforum.com/showthread.php?t=1100

http://www.bautforum.com/showthread.php?t=3544

http://www.clavius.org/gravleap.html

antoniseb
2006-Mar-24, 12:36 AM
If you were to assume a domed habitat on the various worlds with conditions such that a human could comfortably wear a track uniform, it would be possible for someone to jump roughly six times as high on the Moon as on the Earth. Likewise about two and a half times as high on Mars as on the Earth.

When measuring how high someone can jump, for this purpose, you should consider how high a person's center of gravity is lifted in the jump. Thus a two meter tall high jumper starts with his center of gravity about a meter off the ground already. When he jumps to clear the bar, he can twist his body such that the center of gravity is never actually above the bar. It is extraordinary for someone to raise his center of gravity more than a meter, even when clearing a bar two meter off the ground. This same athelete who jumps over a bar two meters up could clear a bar 3.5 meters high on Mars, and 7 meters high on the Moon.

Note that it would take some practice for an athlete to achieve this because his muscles are tuned to be most efficient on the Earth.

joema
2006-Mar-24, 02:17 AM
...This same athlete who jumps over a bar two meters up could clear a bar 3.5 meters high on Mars, and 7 meters high on the Moon...
Good point. There were many old references from the 50s and 60s saying a person could jump 36 feet (11 m) high on the moon. They simply took what an athlete high jumper could clear on earth -- about 6 ft (1.8 m) -- and multiplied by six. That's obviously wrong. On earth much of a high jumper's clearance is achieved by body position, which you don't multiply by six on the moon.

As you pointed out the height would be closer to 7 meters (23 ft), and that would take an expert. I'd guess the average unencumbered person could jump about 12 ft (3.7 m) high (about 6x the distance of a vertical jump on earth with legs down), including a couple of feet for pulling your legs up. A basketball player might jump 16-18 ft (4.9 m - 5.5m) high.

GDwarf
2006-Mar-24, 02:20 AM
The current high-jump record is 2.45m, on the moon, with proper training, and no bulky suit, the record would've been 14.7m, or 49 feet, pretty impressive.

Edit: D'oh, he wouldn't jump exactly that high, but it'd be somewhere around that, wouldn't it?

DALeffler
2006-Mar-24, 02:44 AM
Moon Olympics!

I want tickets to the Pole Vault....

But how 'bout track events? How fast can you run on the moon?

At first blush, I'd think 1/2MV^2 would preclude any contact sport...

Denis12
2006-Mar-24, 02:44 AM
I will try to measure my jump tomorrow ,i want to know how high you can jump on earth,because gravity is also a great interest for me. I hope for another sunny day tomorrow. I look forward to see the first astronauts jumping on Mars. And on its moons ,Phobos and Deimos,but that will be a (very) high jump i think.

antoniseb
2006-Mar-24, 02:52 AM
And on its moons ,Phobos and Deimos,but that will be a (very) high jump i think.

I think that on Phobos and Deimos, you could jump and not come back down, if you jumped with as much force as a human can put into a jump.

joema
2006-Mar-24, 04:29 AM
The current high-jump record is 2.45m, on the moon, with proper training, and no bulky suit, the record would've been 14.7m, or 49 feet, pretty impressive.

Edit: D'oh, he wouldn't jump exactly that high, but it'd be somewhere around that, wouldn't it?
No, as I tried to explain above, you can't take the current high jump record and multiply by six.

If that same high jumper on earth simply jumped straight up with legs vertical (like trying to touch a basketball rim), his feet would only be about 3 ft (< 1m) off the floor). THAT is the number you multiply by six to approximate jumping height on the moon.

Of course the above would require an unencumbered person, which means a large pressurized dome.

But jumping is nothing -- inside that pressurized dome at 1/6 g, you could strap on wings and fly like a bird.

Kaptain K
2006-Mar-24, 05:10 AM
But jumping is nothing -- inside that pressurized dome at 1/6 g, you could strap on wings and fly like a bird.
See Menace from Earth by Robert A Heinlein.

The Saint
2006-Mar-26, 04:05 PM
Are there any photos or footage of Armstrong's 5-6' jump?

Jeff Root
2006-Mar-26, 06:50 PM
I'm not going to do much research to verify this. My recollection
is that Armstrong said that he was not going to take any chances,
on the very first EVA on the Moon, so he didn't try to jump very
high, and didn't jump nearly as high as later astronauts did.

However, in order to get back up to the lowest rung of the ladder,
he did have to jump up about three feet, with the help of his hands
on the ladder. He did that before he stepped off of the LM footpad,
to test what he would have to do at the end of the EVA.

The distance from the lowest rung of the ladder to the footpad
prompted Pete Conrad, on Apollo 12, to say, "Whoopee! Man, that
may have been a small step for Neil, but that's a long one for me!"
Conrad was the shortest Apollo astronaut.

-- Jeff, in Minneapolis

Ken G
2006-Mar-27, 03:13 AM
Here's another factor to consider. The six-times-higher idea is predicated on the idea that you can generate a certain upward speed, or a certain upward kinetic energy, independently of the gravity you are in. This in turn requires that your muscles are capable of generating a given force over the distance of your leg extension. But this is not likely to be a correct assumption. My guess is you could jump even higher, because your muscles would not be working against the force that they need just to keep you in place on the Earth. Thus one needs to calculate the maximum leg force you can generate, and note that the work you are doing on Earth requires that you subtract what corresponds to 1 g, but on the Moon, you would only need to subtract 1/6 g. That means more force is available for doing work and creating accelerating, hence higher speed and higher kinetic energy, and more than a 6 times increase in height of lifting of the center of mass. However, it is also possible that your muscles simply could not generate this added force, as there may be a limit as to how fast you can uncoil said muscles. If this latter point holds, even the 6 times figure could be an overestimate. I'm afraid this is issue is likely to be an experimental question, and theory can only give a rough idea!

The Saint
2006-Mar-27, 09:44 AM
So how far could a golf ball have theoretically and realistically have been driven by an astronaut on the Moon (on the Earth the record is 515 yards)? Was this ever attempted?

antoniseb
2006-Mar-27, 11:50 AM
So how far could a golf ball have theoretically and realistically have been driven by an astronaut on the Moon (on the Earth the record is 515 yards)? Was this ever attempted?

A few golf balls were hit by Alan Sheppard. He did not attempt to set the maximum record for golf-ball distance, since he had to swing one-handed, encumbered by a space suit, and using a dirt scoop for a club. He also didn't go after the ball with a measuring tape.

If you had a very large domed golf course on the moon, the distance you'd expect would be 3090 yard (assuming 1/6th gravity on the moon is accurate to three places). This distance would not be achieved because air resistance on such a flight would affect the ball. What's the air pressure?

On the other hand, if you were hitting it in the vacuum but not encumbered by a space suit somehow, you could hit a ball a good bit further than 3090 yards.

Here's another related question. If you were in a habitat on the moon with an Earth like atmosphere, could you hit a ping pong ball any further? (no).

Irishman
2006-Mar-27, 11:42 PM
Technically, Shepard had a club head attachment on the end of the dirt scoop. It was an actual club, but the handle and shaft were wonky.

The Saint
2006-Mar-27, 11:50 PM
Are there any photos or footage of Shepard golfing? On Earth at ground level the horizon is about 4 miles away. How far is the horizon on the Moon?

antoniseb
2006-Mar-28, 12:21 AM
There is video of Sheppard golfing. I remember watching it when it happened. I couldn't really see the ball.

Denis12
2006-Mar-28, 01:38 AM
Are there any photos or footage of Shepard golfing? On Earth at ground level the horizon is about 4 miles away. How far is the horizon on the Moon?
I dont know how far the horizon really is on the Moon ,but i think much closer than here on earth.

Irishman
2006-Mar-28, 07:33 PM
Tried some geometry to solve the problem.

If a person is standing on the surface of Earth, then their horizon is a straight line from eyes (line of sight) to the tangent point on the surface of the Earth in the distance.

From the following website, measuring Tangents to circles
http://library.thinkquest.org/20991/geo/circles.html

Define a circle with two lines, one the radius and the other the radius + the height to the tangent line from the first point. On the second line, let A be the center point, B the intersection with the surface, C the intersection with the Tangent line. From Pythagorean Theorem we can find the length of the tangent line.

CD2 = AC2 - R2

Plugging in that AC = R + h, rearranging, we get

CD = sqrt (2Rh + h2)

So Radius Earth = Re = 3963.3 mi
height = h = 6 ft

CD = 3 mi.
Doesn't match 4 miles.

For the Moon
Rm = 1079.9 mi

then CD = 1.567 mi.

The Saint
2006-Mar-28, 08:59 PM
You're right. According to this table, for a 6' man the horizon is 3.1 miles.
http://www.pvv.ntnu.no/~bcd/shadowworld/info/horizon.html

Grey
2006-Mar-28, 10:47 PM
You're right. According to this table, for a 6' man the horizon is 3.1 miles.
http://www.pvv.ntnu.no/~bcd/shadowworld/info/horizon.htmlThe figures are close enough for casual purposes, but note that this page is talking about the distance to the horizon on a fictitious planet which is apparently slightly larger than Earth.

Ken G
2006-Mar-29, 01:03 AM
There could be some bending of light rays in some situations, I would guess, but maybe that isn't very important.

joema
2006-Mar-31, 11:55 PM
So how far could a golf ball have theoretically and realistically have been driven by an astronaut on the Moon (on the Earth the record is 515 yards)? Was this ever attempted?
The typical golf ball speed right off the club head is about 250 f/s (76 m/s). The formula for distance is:

R = V^2 * sin (2 theta) / g, where
R = range in meters
V = velocity in m/s
theta = projectile angle
g = gravitation acceleration (1.63 m/s on the moon)

R = 76^2 * sin (2 * 45) / 1.63
R = 3,536 meters

grant hutchison
2006-Apr-01, 11:54 AM
There could be some bending of light rays in some situations, I would guess, but maybe that isn't very important.It turns out to be quite important. One rule of thumb for calculating the horizon distance on Earth is that atmospheric refraction reduces the apparent curvature of the Earth's surface by a sixth: the equivalent of being on the surface of an airless planet with 20% greater radius than Earth.

Grant Hutchison

joema
2006-Apr-01, 01:16 PM
I dont know how far the horizon really is on the Moon ,but i think much closer than here on earth.
Distance to lunar horizon is given by the formula:

D = 2636.6 * SQRT(h), where
D = distance to horizon in meters
h = height above ground in meters

Suppose h = 1.8 meters (height of lunar astronaut's eyes)

D = 3537 m or 3.537 km

By amazing coincidence, almost the same distance a golf ball would travel, assuming ideal exit speed and 45 deg. departure angle.

joema
2006-Apr-01, 01:54 PM
Re jumping on the moon, here's a video of astronaut John Young's "jump salute" on Apollo 16 (2.7 MB MPEG-1): http://www.hq.nasa.gov/alsj/a16/a16salute.mpg

He's not jumping at max effort, but seems to be jumping pretty hard. He doesn't go all that high.

Here's a still picture of him at the jump apex: http://www.clavius.org/jumpsal.html

Astronaut Dave Scott throws a discarded piece of equipment, almost falling down doing so: (525 kb .MOV) http://www.hq.nasa.gov/office/pao/History/alsj/a15/a15v_1244753.mov

Denis12
2006-Nov-28, 09:11 PM
Tomorrow i try again jumping on the local sandy beach because i want to know exactly the height of my jump ,and i expect a sunny day with blue skies. So i hope i can reach 1 meter or more while i am jumping. A friend of mine will try to measure it. How was it measured on the apollolandings on the Moon? (the jumps of the astronauts)

PhantomWolf
2006-Nov-28, 09:19 PM
Bob B., I think it was, did csome calculations based on the Mythbusters' measurements for jumping speed (they did it for surviving an elevator drop.) He worked out that given the speed of launch, the most you could jump on the moon is only about 6-7 feet. Add a restrictive suit and Armstrong's 5-6 foot jump up onto the top rung of the LM ladder was probably the best that any of them could have done.

phunk
2006-Nov-28, 09:25 PM
It wasn't measured, just estimated visually.