Q:

Why is there no air in space?

A:

There is no air in space because there is no gravity to condense the molecules of gases found there into air. On Earth, gravity holds nitrogen, oxygen and the other gases that compose the atmosphere together, but only to about 60 miles above the surface.

Know More

Full Answer

A few particles of dust and molecules of gases float in space. Scientists call this mixture interstellar medium. The particles and molecules in interstellar medium are so rare that many people think of space as a perfect vacuum. While it is closer to a perfect vacuum than anything man is able to create on Earth, it is not perfect. Interstellar medium is 99 percent gas, but the gas molecules are very far apart, and hydrogen is the most common gas in the mix. Interstellar dust particles are too small to see with the naked eye and are composed of silicates, iron, ice crystals and carbon.

The air at the surface of Earth has many molecules of gases in a small space. As the distance from the surface increases, the relative concentration of the gases decreases, meaning the air becomes thinner. At the 60-mile level, the concentration begins to change and the atmosphere is primarily lighter gases, such as hydrogen or helium, and closer to the composition of interstellar medium.

Learn more in Astronomy

Related Questions

  • Q:

    How does gravity keep us on Earth?

    A:

    Gravity is one of the fundamental forces of the universe, and it keeps us on Earth because it is relentlessly attractive. Every massive particle exhibits gravity by pulling closer to every other particle. The strength of this interaction is dependent on two quantities: the amount of mass and the distance between objects. It is possible to escape Earth's gravity if you have enough energy to speed up sufficiently.

    Full Answer >
    Filed Under:
  • Q:

    What do you call a cloud in space that is composed of dust and gas?

    A:

    A cloud in space that is composed of dust and gas is call a nebula. The word "nebula" is derived from the Latin word for "cloud," and nebulae in space are indeed large  interstellar clouds made up of dust, hydrogen, helium and plasma.

    Full Answer >
    Filed Under:
  • Q:

    What are "wormholes"?

    A:

    In theoretical physics, wormholes are points in space that act as an entrance and exit system for travel that is faster than the speed of light between two points. Scientists do not know of any existing wormholes, and the hypothesis rests on conclusions from other scientific theories.

    Full Answer >
    Filed Under:
  • Q:

    What is a dead star?

    A:

    A dead star is a star that has exhausted all its fuel for nuclear fusion and is simply the core of the former star floating through space. The size of the star before it uses up all its fuel determines what happens to it afterward.

    Full Answer >
    Filed Under:

Explore