Planets and others objects have one... but do people have a gravity field?

Question

I've heard so often that everything around us has some form of gravity field that can attract other things to each other. This is definitely true with things such as planets, stars and other large celestial objects... but do small things like people and buildings have a small field?

I am being serious here... no joke!

Answer 1

Everything that has mass has a gravity field. With very small things, like atoms, the gravity is much weaker than other forces like the strong and weak nuclear forces, but even atoms have gravity.

You can calculate the gravity of someone else on you. The force of your mutual gravity is calculated by

F = (G * m1 * m2)/(d^2)

m1 = your mass
m2 = someone else's mass
d = the distance between you two
G = the gravitational constant, 6.6742 * 10^(-11) m^3/s^2 * kg

Let's say you mass about 55 kg and someone else masses 60 kg (that's about 121 and 132 pounds on Earth). The two of you stand so that your bodies are about one meter apart, as if you are shaking hands. That is

F = 6.6742 x 10^(-11) (m^3/s^2 x kg) * 55 kg * 60 kg / (1m ^ 2)
F = 2.2025 x 10^(-7) (kg * m / s ^ 2)
F = 0.00000022025 (kg * m / s ^ 2)

When you consider that the force attracting you to the Earth is 55 kg * 9.8 m / s^2, or 539 (kg * m / s ^ 2), you can see why you don't feel a gravitational attraction to whomever is standing next to you.

Answer 2

Yes, any object with mass has a gravity field...

However, humans have such little mass that the gravity they exert is insanely small... gravity itself is a "weak" force in that it takes an enourmous amount of whatever causes gravity (which we still have yet to figure out, even though we know its magnitude is directly proportional to mass as I explain below) to actually effect a force on something...

We can however, explain it mathematically with the equation below...

F = GMm/r^2 ... where G = Newton's Gravitational constant
M = mass of attracting body (Earth, Sun, Mars, a person, a moon, whatever as long as it has mass)
m = mass of the attracted body (same conditions as above)
r = distance between the two...

And you will notice that gravity creates an "inverse squared" field... this means that the farther you get from the source of gravity, the weaker its pull by a squared amount... meaning if you double the distance... the force is 25% of what it was...

Answer 3

Absolutely, every single thing that contains mass or energy emits gravity. The reason why we aren't being sucked into buildings is that buildings are very very light, their gravity is so weak that even the speeds of an ant significantly overcomes the building's force of gravity. But definitely we have gravitational fields, they're just unbelievably small. This also shows just how weak the force of gravity is. Even the Earth, so massive. Yet we can easily lift let's say a book up, yet the entire Earth is pulling on it.

Answer 4

I'm glad to read some serious questions here!

In answer to your question, yes, anything that has a mass has some gravity field and that includes "small things like people and buildings". The reason smaller objects like cats or bowling balls do not just instantly flow towards larger objects like you or a station wagon is because the gravity fields themselves are so infinitisemally small as to be virtually unnoticeable.

Hope that's serious enough.

Answer 5

Yes. Every two objects in the universe attract each other through gravity. Every object has a corresponding gravitational field around it. HOWEVER, the strength of the field is determined by the amount of mass an object has, so for people, the strength is very small. One way to measure the gravitational constant (G) is to precisely measure the amount of attraction between two iron spheres in a lab.

Answer 6

The attractive force between two bodies (e.g., Earth (M) and you (m)) is proportional to the product of the two masses divided by the square of the distance between them. Because M >>>>>> m (which means Earth is way bigger than you), all but a small percentage of the total force of gravity on you stems from the Earth's mass.

By the way, F = ma, right? If the force (F) is from gravity, we call it weight (W). So we have W = ma. What do you suppose the force equation's a is when we talk about the force of gravity on Earth's surface?

Turns out a = g ~ 32 ft. per sec sec. So if you weigh 160 pounds at sea level, what is your mass (m). m = W/g = 160/32 = 5 pound-ft/sec-sec. In the pound realm, a unit of mass is sometimes called a "slug." So your mass would be 5 slugs, which is a horrible thing to imagine...don't you think?

Answer 7

Of course you do. And there are plenty of people here who have answered the question very well.
But let's have a little bit of fun with your gravity field. Ask yourself this: "How compressed would you have to be to become a black hole?"

How do you determine this? Very simple. The equation for escape velocity of a gravity field is: v=(2GM/r)^(1/2)
That is to say that escape velocity is the square root of 2 times the Universal Gravity Constant (6.67x10^-11) times your mass divided by your radius.

To find out how small you would be as a black hole, simply enter the speed of light as the escape velocity and the solve the equasion for the radius.

My personal Schwarzschild radius (the point where the escape velocity = C) is about 1x10^(-25) meters. That is how small a space I would have to cram my 75 kg into to become a black hole. Imagine how it would feel!

That is 0.0000000000000000000000001 meters. Compare that to the size of an atom which is about 0.0000000001 meters.

That's pretty small!

Answer 8

Everything with mass has a 'gravity field'.

Just think, all the boys in your class are gravitationally attracted to you. In fact, all the boys in the world are gravitationally attracted to you, since the force of gravity extends forever (Edit: and just ignore that mean spirited mathematician guy that claims that guys' attraction for you is very small. In fact, I'd definitely not choose his answer as best!)

F = G(m1)(m2)/r^2 where G is the universal gravitational constant, m1 is one body of mass, m2 is the other body of mass, and r is the distance between the two masses.

No matter how large the distance is between two masses, the gravitational force between them never quite reaches zero. Every star you see in the sky tugs on you just a little bit.

No matter how small the masses are relative to the distance, the gravitational force between them never quite reaches zero. You tug on every star you see in the sky just a little bit.

Everything that happens in the universe affects you. Likewise, your presence affects every other thing in the universe. Kind reminds me of an Emerson, Lake, and Palmer song: "It is perfectly clear .... you were meant to be here...... From the beginning."

Answer 9

Yes, but the gravity is very small, and easily overcome by pushing one another away, assuming they were floating freely in space (presumably in space suits).

In the presence of a major gravity field, an individual's gravity is negligable, although Newton pointed out that a person (or apple) is just as much attracting the Earth/ground as vice-versa.

Answer 10

Any object with any mass whatsover will bend space around their "Center of Gravity".

If you drop a pebble off of a cliff, you will see the pebble tracking towards the cliff wall by force of the gravity field about the cliff.