why does the.....?

Question

why does the earth revolve around the sun and not the sun around the earth?

why do the planets move in an eliptical shape and not just randomly move?

what makes the sun so speical that it is the center of the universe?

i have always wondered why if we are the only planet to hold life then why couldnt everything revolve around the earth?

Answer 1

The earth revolves around the sun because the sun has much more gravity than the earth

Gravity

our solar system revolves around the sun, the sun revolves around the galactic center of the milky way

gravity

Answer 2

The Earth revolves around the sun because the sun has a much larger mass and thus a much higher gravitational pull on objects than the earth does.

Planets move the way they do because they are in orbit of their parent star (eg. our sun).

The sun is not special (apart from to us) and is most certainly NOT the center of the universe. Such a view would be very religious and extremely old fashioned.

There is no way for us to tell at out current stage of technology if Earth is the only planet that supports life. There are over 700,000,000,000 (seven hundred thousand million) stars in our galaxy alone and there are more galaxies in the universe than grains of sand on planet earth. That being the case, I find it extremely unlikely that there are no other planets with life... The problem is the great distances involved.
Chances are that another planet with life on is so far away that the light from that planet would not have reached Earth since life evolved on Earth (we have not been here very long in cosmological terms).

Answer 3

1.)  Actually, the Earth and Sun orbit around a common point, called the barycenter (aka the "center of mass").  This is the point on the Earth-Sun line where the product of the distances from the centers times the masses is the same.  However, since the Sun is about 200,000 times as heavy as the Earth, the center of the Sun is 200,000 times closer to the barycenter than the center of the Earth.  If you divide the 93,000,000 mile Earth-Sun distance by 200,000, you get 465 miles.  465 miles from the exact center of the Sun is still inside the Sun's core, so the Sun barely moves.

2.)  Planets move in ellipses because two quantites are conserved:  energy and angular momentum.  If a planet comes closer to the Sun, some gravitational energy is converted to kinetic energy and it moves faster; if it falls away from the Sun, it converts kinetic energy to gravitational energy and it moves slower.  Conservation of angular momentum means that the product of the length of the planet-Sun line and the planet's speed perpendicular to that line remains the same.  If you solve the differential equations for the motion of a planet given these constraints, you get a conic section:  a circle, ellipse, parabola or hyperbola.  A planet on a parabolic or hyperbolic orbit would go by once and never come back, so the ones we see (plus things like asteroids and comets) travel on ellipses.

3.)  Earth is just the only place we know has life.  There could be lots of other places with life, and we haven't even had a good look at them yet.  Scientists want to investigate the planet Mars and the moons Europa and Titan because they think the conditions either are or were suitable for life there.

Life needs a source of energy, like a star.  However, stars are much too hot to host life as we know it.  Since stars are much heavier than Earth-like planets, planets with life like ours will go around stars rather than the reverse.  Consider it Nature's way of keeping us humble.

Answer 4

1. It's not a "why" thing; it just is. The earth is in orbit around the sun.

2. The planets are in orbit around the sun. They cannot move randomly, because an orbit is required to balance gravity and centrifugal force.

3. The sun is not the center of the universe. The center of the universe is indeterminate.

4. We are not the only anything, and the solar system is only a tiny bit of dust in a remote corner of a small part of almost the tail end of nowhere. We are not really very important in the scheme of things.

Answer 5

1) Because the Sun weighs a lot more than the Earth, and that's the principle driver of gravitational orbits - the lighter thing goes around the heavier thing.

2) Gravity keeps them in orbit.

3) It's not. It's only the center of our solar system. It's out near the edge of our galaxy, which is only one of billions in the universe.

4) Life doesn't make things revolve around each other, mass does. And there's a very good chance there's life out there in the universe somewhere, not just on Earth. When you think about it, we've really only checked one other planet out of billions in our galaxy alone.

Answer 6

1) Gravity comes from the sun

2) Gravity

3) Its not the center of our universe. Its the center of the solar system. And you're right, its not special. It just gives us life.

4) How do you know we are the only planet to hold life? Have you been all over the universe? It doesn't work that way. The sun is the source of the gravity. If Earth was, then things would revolve around Earth. But it doesn't.

Answer 7

The sun is 300000 times heavier than the earth. Gravity rules.

The planet orbit elliptically because this is a stable orbit, and they are in orbit because this is an equilibrium between their speed and how deep they are in the sun's gravity field.

The sun is NOT the center of the universe. It is not the center of out galaxy. It is ONLY the center of our solar system. And it is the center of our solar system because it is much heavier than all the planets combined.

The presence of life does not affect the motion of celestial bodies. There was a time when there was no life on earth, do you think it would have shifted orbit after life appeared?
What about when astronauts went to the moon? Suddenly there was life on the moon, should the moon change its orbit at that time?

Answer 8

for the sun thing the answer is the law of universal gravitation, which means everything is atracted to everything. so because the sun has a bigger mass, it has more gravity so everything in the solar system is attacted to the sun. oh and the sun isnt the center of the universe

Answer 9

G R A V I T Y

and the sun is not the centre of the universe. the sun is the centre of the solar system (and thats why its called the solar system in the first place)

Answer 10

Gravity

Gravity

It's the center of the Solar System, the universe has no center.

Gravity