PV Gap

Tiffany Said:

what is a good question and test for a space /solar system science project ?

We Answered:

hang a large object next to a small object and see if you can show any gravitational pull, of one object to the other : )

Salvador Said:

Question about the arrangement of the members of the solar system in space?

We Answered:

They all follow the same east to west direction because that is apparent motion caused by the Earth's rotation. The fact that they all follow roughly the same path through the sky means that they all lie on roughly the same plane. This is an inevitable consequence of the way the solar system was formed.

Kurt Said:

If space is really expanding, and at the rate it supposedly is, then why do we not see it in the solar system?

We Answered:

Universal *space* is expanding. There's just too much good, observed evidence for it. Everything in the universe is embedded in space. . .you, me, stars, galaxies, etc.,. However we can't leave gravity out of the equation. If two massive objects, like a couple of galaxies, are relatively close to each other, their mutual gravitational attraction will cause them to move *towards* each other *through* the space in which they're embedded; there's nothing to oppose that motion because even though they might be moving counter to spatial expansion, space itself offers no resistance to their movement. A good example is our Milky Way galaxy and the Andromeda Galaxy which are currently heading towards each other because of their mutual gravitation and relative nearness.

Another example is the space within our bodies. Were it not for the super-strong intensity of the nuclear forces, we couldn't exist in an expanding universe.

On the other hand, if two galaxies are separated by something like 500-million light years, the expansion of space will cause them to move away from each other because they're just too far apart for gravity to overcome that expansion (...remember, the strength of gravity decreases by a factor of 4 for every doubling of the distance from its source..)

Minnie Said:

If I travelled through the solar system and into space, what kinds of noise would I hear?

We Answered:

You wouldn't hear anything, *nothing* makes a sound in space.

Sound is a travelling wave which is transmitted through a solid, liquid or gas. Space is vacuum; vacuum is a volume of space that is essentially empty of matter.

Julia Said:

Questions on space, solar system, etc for homework...?

We Answered:

The solar system is mainly made out of the sun's stardust and debris left over when the Sun was formed 4.57 billion years ago.

The string theory is the theory that scientists think that the electrons and quarks within an atom are not 0-dimensional objects, but 1-dimensional strings. These strings can move and vibrate, giving the observed particles their flavour, charge, mass and spin. This is also called the theory of everything.

The big bang theory posits that before the universe was born, it was an egg that was microscopic. Somehow, it exploded. Until now, the universe is still expanding.