Force needed to lift the Earth?

SLAM: debunk creationism, pseudoscience, and superstitions. Discuss logic and morality.

Moderator: Alyrium Denryle

Post Reply
User avatar
The Grim Squeaker
Emperor's Hand
Posts: 10315
Joined: 2005-06-01 01:44am
Location: A different time-space Continuum
Contact:

Force needed to lift the Earth?

Post by The Grim Squeaker »

Having recently looked at the famous tale of Hercules holding up the planet, I was curious as to how muc force he would need to exert for this feat.

The mass of the Earth = 5.9742×10^24 kilograms [according to a quick Google].

Now, the question is how much gravity would be exerted, by the sun and other planets as well as the famous gravitational constant.
If the Gravity is merely Earth's normal exerted gravity or that exerted by the sun then wouldn't the Force needed be F=ma with a=the gravity and m=mass of the earth (Or the "Weight" of the earth affected by the gravity of the sun?).

For the sake of the argument the lifter can stand in air and can extend a field so that the force exerted on the planet is spread out and doesn't rip the atmosphere/oceans/etc' away.
Photography
Genius is always allowed some leeway, once the hammer has been pried from its hands and the blood has been cleaned up.
To improve is to change; to be perfect is to change often.
User avatar
Darth Wong
Sith Lord
Sith Lord
Posts: 70028
Joined: 2002-07-03 12:25am
Location: Toronto, Canada
Contact:

Post by Darth Wong »

Do a handstand. There; you just exerted enough force to lift the Earth ... relative to your own torso. Or did you forget that you have to define an external frame of reference for this?
Image
"It's not evil for God to do it. Or for someone to do it at God's command."- Jonathan Boyd on baby-killing

"you guys are fascinated with the use of those "rules of logic" to the extent that you don't really want to discussus anything."- GC

"I do not believe Russian Roulette is a stupid act" - Embracer of Darkness

"Viagra commercials appear to save lives" - tharkûn on US health care.

http://www.stardestroyer.net/Mike/RantMode/Blurbs.html
User avatar
The Grim Squeaker
Emperor's Hand
Posts: 10315
Joined: 2005-06-01 01:44am
Location: A different time-space Continuum
Contact:

Post by The Grim Squeaker »

Darth Wong wrote:Do a handstand. There; you just exerted enough force to lift the Earth ... relative to your own torso. Or did you forget that you have to define an external frame of reference for this?
Heh, good point. (Sorry for being Vague).

I mean the force necessary to either stop the earth in it's orbit, to push it out of it's orbit or to "hold" it in place while preventing it from moving.

If these examples are too obscure then the force needed to Hold the Earth and lift it and hold it in place is also useful (Similair to the famous Hercules/Atlas feat of myth), the question is how much gravitational force would be exerted by the sun and other objects in the solar system on it.
Photography
Genius is always allowed some leeway, once the hammer has been pried from its hands and the blood has been cleaned up.
To improve is to change; to be perfect is to change often.
User avatar
Prozac the Robert
Jedi Master
Posts: 1327
Joined: 2004-05-05 09:01am
Location: UK

Post by Prozac the Robert »

DEATH wrote: I mean the force necessary to either stop the earth in it's orbit, to push it out of it's orbit or to "hold" it in place while preventing it from moving.
I supose you could work out the force required to hold the earth still relative to the sun.

You'd need to do work to stop the circular motion, and then a constant force of GMm/(r^2) to hold it against the sun's gravity.

Rotation:
The Earth apparently has mean orbital velocity of 29.78 km/s, or 2.978*10^2 m/s.
Therefore it has a kinetic energy of 2.965*10^23 Joules. That's how much workwould need to be done to stop that. The force required depends on how long you have to do that.

Radial force:
This requires a constant force of 3.56*10^22 Newtons, provided I have that calculated right.
Hi! I'm Prozac the Robert!

EBC: "We can categorically state that we will be releasing giant man-eating badgers into the area."
User avatar
AK_Jedi
Padawan Learner
Posts: 441
Joined: 2005-12-14 11:26pm
Location: the middle of nowhere

Post by AK_Jedi »

The sun exerts approx. 3.5x10^22 newtons of force on the Earth. If the Earth were to stop revolving around the sun, this is how much force you would need to hold it up, not taking the moon into account. Most of the time, the other planets exert negligible force on the Earth.
Why does he keep looking at you in the same way a starving man looks at a packet of peanuts?
It's because he can't wait to get the wrapper off and taste the salty goodness! --Kryten, Red Dwarf

Understanding is a very loaded word. --Dr. Paul
User avatar
Dooey Jo
Sith Devotee
Posts: 3127
Joined: 2002-08-09 01:09pm
Location: The land beyond the forest; Sweden.
Contact:

Post by Dooey Jo »

Prozac the Robert wrote:Rotation:
The Earth apparently has mean orbital velocity of 29.78 km/s, or 2.978*10^2 m/s.
Therefore it has a kinetic energy of 2.965*10^23 Joules.
29.78 km/s is actually 2.978e4 m/s...
Also, the mass of the Earth is about 6e24 kg, so the kinetic energy,
E = (m*v^2) / 2
would be
(6e24 * (2.978e4)^2) ) / 2 = ~3e33 J
Image
"Nippon ichi, bitches! Boing-boing."
Mai smote the demonic fires of heck...

Faker Ninjas invented ninjitsu
User avatar
Prozac the Robert
Jedi Master
Posts: 1327
Joined: 2004-05-05 09:01am
Location: UK

Post by Prozac the Robert »

Dooey Jo wrote: 29.78 km/s is actually 2.978e4 m/s...
Also, the mass of the Earth is about 6e24 kg, so the kinetic energy,
E = (m*v^2) / 2
would be
(6e24 * (2.978e4)^2) ) / 2 = ~3e33 J
Umm, no idea why I wrote that speed. I plead temporary stupidity.

Also, that speed doesn't seem to give the answer I gave anyway, so at least it's possible that I didn't type 2.978e2 into the calculator. I think I must have just mashed some wrong buttons. I've just finished the third year of a physics degree, and I can't even correctly operate a calculator, or reliably write down a number in standard form. How pathetic is that.

Thanks for sorting that out.
Hi! I'm Prozac the Robert!

EBC: "We can categorically state that we will be releasing giant man-eating badgers into the area."
User avatar
Molyneux
Emperor's Hand
Posts: 7186
Joined: 2005-03-04 08:47am
Location: Long Island

Re: Force needed to lift the Earth?

Post by Molyneux »

DEATH wrote:Having recently looked at the famous tale of Hercules holding up the planet, I was curious as to how muc force he would need to exert for this feat.

The mass of the Earth = 5.9742×10^24 kilograms [according to a quick Google].

Now, the question is how much gravity would be exerted, by the sun and other planets as well as the famous gravitational constant.
If the Gravity is merely Earth's normal exerted gravity or that exerted by the sun then wouldn't the Force needed be F=ma with a=the gravity and m=mass of the earth (Or the "Weight" of the earth affected by the gravity of the sun?).

For the sake of the argument the lifter can stand in air and can extend a field so that the force exerted on the planet is spread out and doesn't rip the atmosphere/oceans/etc' away.
Just a nitpick..but Hercules did NOT hold up the Earth. He was, in fact, standing *on* the Earth and holding up the sky, taking the job over from Atlas temporarily.
Ceci n'est pas une signature.
User avatar
Qwerty 42
Jedi Council Member
Posts: 2008
Joined: 2005-06-01 05:05pm

Re: Force needed to lift the Earth?

Post by Qwerty 42 »

Molyneux wrote:
DEATH wrote:Having recently looked at the famous tale of Hercules holding up the planet, I was curious as to how muc force he would need to exert for this feat.

The mass of the Earth = 5.9742×10^24 kilograms [according to a quick Google].

Now, the question is how much gravity would be exerted, by the sun and other planets as well as the famous gravitational constant.
If the Gravity is merely Earth's normal exerted gravity or that exerted by the sun then wouldn't the Force needed be F=ma with a=the gravity and m=mass of the earth (Or the "Weight" of the earth affected by the gravity of the sun?).

For the sake of the argument the lifter can stand in air and can extend a field so that the force exerted on the planet is spread out and doesn't rip the atmosphere/oceans/etc' away.
Just a nitpick..but Hercules did NOT hold up the Earth. He was, in fact, standing *on* the Earth and holding up the sky, taking the job over from Atlas temporarily.
Although the mental image of Atlas standing on his hands for years at a stretch is thoroughly amusing.
Image Your head is humming and it won't go, in case you don't know, the piper's calling you to join him
User avatar
The Grim Squeaker
Emperor's Hand
Posts: 10315
Joined: 2005-06-01 01:44am
Location: A different time-space Continuum
Contact:

Re: Force needed to lift the Earth?

Post by The Grim Squeaker »

Qwerty 42 wrote:
Molyneux wrote:
DEATH wrote:Having recently looked at the famous tale of Hercules holding up the planet, I was curious as to how muc force he would need to exert for this feat.

The mass of the Earth = 5.9742×10^24 kilograms [according to a quick Google].

Now, the question is how much gravity would be exerted, by the sun and other planets as well as the famous gravitational constant.
If the Gravity is merely Earth's normal exerted gravity or that exerted by the sun then wouldn't the Force needed be F=ma with a=the gravity and m=mass of the earth (Or the "Weight" of the earth affected by the gravity of the sun?).

For the sake of the argument the lifter can stand in air and can extend a field so that the force exerted on the planet is spread out and doesn't rip the atmosphere/oceans/etc' away.
Just a nitpick..but Hercules did NOT hold up the Earth. He was, in fact, standing *on* the Earth and holding up the sky, taking the job over from Atlas temporarily.
Although the mental image of Atlas standing on his hands for years at a stretch is thoroughly amusing.
True.
Man I feel Humiliated, I who had read the Odyssey (Translated heavily albeit and in a illustrated formal) At age 8 misinterpreting this.
The shame I would request a boon to Kill myself but Seppuku is Japanese so scratch that :P .
Still The weight os the sky according to Here is 5.3 x 10^18 kg.
So Lifting it and holding it would require overcoming Earth's gravitational pull (Standardized, though it would weaken due to the ranges involved):
F=ma
m=5.3 x 10^18 kg
a=g=9.81 m/s^2
So Herc would need to sustain a force of 5.1993 × 10^19 Newtons.
We know that he needed to switch with Atlas and didn't lift it any further so this is the limit and not a low end limit (As would be the case for lifting the Sky up).
Also, the mass of the Earth is about 6e24 kg, so the kinetic energy,
E = (m*v^2) / 2
would be
(6e24 * (2.978e4)^2) ) / 2 = ~3e33 J
Heh, who needs the DS :P (Yeah, yeah 1e38...).
Thanks, I didn't know the speed involved in the earths rotation and whether just the rotation speed needed to be taken into account (Gravitational pull from other Celestial objects etc' spring to mind).
Thanks for the answers
Photography
Genius is always allowed some leeway, once the hammer has been pried from its hands and the blood has been cleaned up.
To improve is to change; to be perfect is to change often.
Post Reply