# Gravity or SupportIf we keep a pen in a table. Why doesn't it fall?   Is it because there is gravity and support!!

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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Hmm! That means that there will be no gravity affects on us if we go to space.

I don't think so, a object will go forever. When we go out of the Exosphere we automatically float in the air inside our shuttle.

OK! According to your theory, we will stop floating and remain constant after sometime if we ourselves don't move.

Am I Correct!

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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Why don't the planets stop as they revolve around the sun?

Because of Newton's first law. In space gravity affects the motion of the planets.  Space is almost empty, so there is no drag, lift, or friction to change a planets motion.

Why does an object stop on Earth.  Again, because of Newton's first law.  There is more stuff on Earth to change an object's motion, like drag, lift, gravity, thrust, friction.

We don't normally think of electrons being involved in drag or friction, but on a microscopic level electric charge is the reason for friction and drag.

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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Why a object stops going in Earth?

You say because the electrons repell.

Why objects don't stop on the Space? For example - Earth rotating around the sun.

Do the electrons don't repell.

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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Why the planets don't stop when they are revolving around the sun?

MAKE IT CLEAR.

And please rate this disscussion. Isn't it a great discussion!

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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I'm not sure who said that an object in space will stop. If you mean outer space, I doubt that an object could be struck by another object with the correct direction and momentum to cause and object to stop, but I suppose that it is possible.

Any object in space, moons, planets, asteroids, and comets, must collect debris as they move through space. Maybe in most cases, the amount would be to small to measure. Comets must lose mass as they move closer to the sun.

The length of the year does change. Every few years astronomers add a leap second to their clocks to adjust it to Earth's change in rotation.

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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You said that a object will stop sometime when we throw it in space.

I don't think so because why the earth and the other planets not stop, they are always travelling i space. Why the year don't become long?

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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Here is an article about NASA using the solar wind to propel space ships. They refer to the  wind as being made of photons, so I suppose that most of the stuff in space is light or engery rather subatomic particles or atoms.

http://www.nasa.gov/centers/marshall/news/news/releases/2004/04-208.html

However, if a space traveler could go to a nebula, maybe there would be more matter than energy.

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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Are there are more atoms in outer space or in Earth?

The density of matter in space is very low, so in that sense Earth has more atoms.

The Sun has more atoms than Earth, so if you think of the Sun as being in space, then space has more atoms.

najm1947 | Elementary School Teacher | (Level 1) Valedictorian

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Gravitational force of earth is pulling the pen towards earth but it cannot fall because there is desk in between so it rests on desk.

Electrons of the atoms of the material of which pen is made do not exist freely but are there with a similar number of protons so the pen has no negative charge and have nothing to do with the gravitational pull except for there contribution to the gravitational force due to their mass.

Space is a void without matter though there are celestial bodies, large and small, floating and moving in the space that are composed of matter.

Matter is composed of atoms that contain protons, neutrons and electrons along with some other smaller particles not yet fully known.

In reply to 7 & 8:

Already explained in reply to 4 above. The electrons have no role as such in the motion of bodies moving in space. If space is being taken in the meaning of atmosphere (air) then air is composed of matter and friction of air due to collisions of the moving bodies with the molecules of gases present in air slows down the moving objects.

It is like reduction in your walking speed through a jam packed crowd. You have collisions with people and can not achieve a speed beyond a certain limit. If the crowd is thin, as is air at higher elevations, the resistance to your movement is less and you can maintain a higher speed. That is why high speed aeroplanes fly at higher altitudes.

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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If there are electrons in outer space, why will a pen continuously move in space..  Why don't the electrons of the pen repel the electrons in the space?

The electrons of the pen do repell the electrons of space, and on a long space journey, the pen slows down.

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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The matter is space or ( in space ) GRAMMAR MISTAKE!!

Ok! If there is electrons in outer space why a pen will continuosly move why don't the electrons of the pen repell the electrons in the space??

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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Are there atoms in space.

The matter is space is protons, electrons, and hydrogen.

etotheeyepi | Student, Undergraduate | (Level 1) Valedictorian

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Or you could say that the pen does not fall because the electrons in the desk repell the electrons in the pen, and the the electrons in the floor repell the desk.  If you had a way to turn off the electrical charges in the atoms, the pen would fall.

Sounds like a great science fiction story.  Where is Isaac Azimov when you need him?

najm1947 | Elementary School Teacher | (Level 1) Valedictorian

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It does not fall because the vertical line passing through the center of gravity (CG) of the pen passes through the plane determined by the extremities of the base of the pen on the desk. As long as this condition is satisfied, the pen will stay in position but when the vertical line passing through CG of the pen goes out of this plane, the pen will fall.

astrosonuthird | Student, Kindergarten | (Level 1) Valedictorian

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I have kept a pen in my desk.

And it has not fall because the desk is blocking the gravity, is it right??