What's It Like In Space

Ever wanted to know some stuff about space?


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Space is fascinating!
Space is big. The universe is larger than we can understand. The universe is so large that stars larger than our Sun or even whole galaxies look like tiny pinpoints of light because they are so far away.
Space contains every bit of matter and energy that has ever existed, and yet most parts of it are utterly empty. In this document, when we talk about deep space, we usually mean the vast stretches of empty area between planets.
Space can be beautiful. The planets, stars, galaxies and nebulae make graceful and colorful shapes visible to our telescopes.
Space can be dangerous. In deep space we would die instantly unless protected. Our home planet the Earth travels through space, with the atmosphere making a cozy blanket between us and the cold and other dangers of deep space.

How Do Things Travel In Space?

Objects in space follow the laws or rules of physics, just like objects on Earth do. Things in space have inertia. That is, they travel in a straight line unless there is a force that makes them stop or change. The movement of things in space is influenced by gravity. Gravity is an important force that can change the course of bodies in space or pull them off of one course, or even cause them to crash together.
While some objects in space travel in irregular paths, most (especially our near neighbors in space) tend to travel in orbits around the Sun or around planets. The orbits are usually close to circular, but are actually slightly flattened ellipses.

Gravity?
Gravity is a very important force. Every object in space exerts a gravitational pull on every other, and so gravity influences the paths taken by everything traveling through space. It is the glue that holds together entire galaxies. It keeps planets in orbit. It makes it possible to use human-made satellites and to go to and return from the Moon. It makes planets habitable by trapping gasses and liquids in an atmosphere. It can also cause life-destroying asteroids to crash into planets.

Energy? In Space?!
There is abundant energy in space. Even though most of deep space (the vast stretches of empty area between planets, stars and moons) is cold and dark, space is flooded constantly by electromagnetic energy. All stars in the universe produce energy and send it out into space. Planets, asteroids and moons reflect that energy back, glowing in the darkness. They can also release energy themselves in the form of heat from volcanoes or other processes. Virtually everything in space is in motion, so there is also kinetic or motion energy in space.

Why Can't the Stars' Light Come To Earth?

There are about 6000+ stars that are clearly visible to the naked eye above Earth. Yet we know that there are millions of stars in the universe. Since all stars are putting out light and other kinds of electromagnetic radiation and since light can travel for huge distances in space, why can't we see all the stars?
All stars, like our Sun, send out a huge amount of electromagnetic radiation, including light. However, that light spreads out with distance, making it so that only a tiny fraction reaches us. In addition, depending on the temperature of the star, the main color of light sent out by the star changes. Cooler stars put out redder light, hotter stars put out blue or white light. Generally, colors like white or blue are stronger colors (shorter wavelength, higher frequency) and can be seen more easily at far distances than reds, oranges or yellows. Also, some stars are simply larger than others and send out more light.