As far as humans can tell, space is infinite; it has no end or borders. Scientists believe that space will always seem infinite to humans for two reasons. First, our investigation of space has never found an edge (or any indications of an edge). Second, measurements show that space is expanding faster and faster, which pushes the edges of the universe ? if there are any ? ever farther out.Continue Reading
Space is continuing to expand (meaning that all the galaxies are speeding away from the center of the universe) because of the Big Bang's momentum and because of a substance called dark energy. Dark energy occupies the seemingly empty parts of the universe, but it has a strong negative pressure, pushing things away from each other even faster than they would move as a result of the Big Bang. This makes it difficult for humans to measure the farthest reaches of space.
In addition, anything traveling through space ? including humans' investigative tools, techniques and measurements ? is limited to the fastest possible speed: the speed of light. Because nothing can travel faster than light, there is a limit to how far scientists can explore or understand the universe. The size of the observable universe (the part astronomers could potentially study) is approximately 45.7 billion light-years across.Learn more about Universe
The type of information about space that is interesting to children includes the number and nature of the planets, the different objects in the universe and the size and nature of the sun. Children find it fascinating to learn that the sun is actually a star that sits at the centre of the solar system. The sun's diameter is 110 times bigger than the earth's and that the sun alone makes up over 99 percent of the solar system's mass.Full Answer >
Observed from space, the United States is the brightest country on the brightest planet in the Solar System because Earth's water makes it the brightest planet and the United States is abundant in artificial lighting, especially at night. Russia is the largest country in the world, Vatican City is the smallest country, and 39 million Vatican Cities could fit inside Russia. In 2011, the global population topped 7 billion people and is expected to reach 10.5 billion by 2050.Full Answer >
Outer space appears dark at night for multiple reasons, the most simple being that the nearest light source, the sun, is blocked by the earth, creating darkness. Outside Earth's atmosphere, outer space appears dark instead of blue because the sun's light is not refracted by atmospheric gases.Full Answer >
The edge of space is generally recognized internationally to be at the Kármán Line, which is 62 miles from the surface of Earth. While the exact boundary of space is open to interpretation, this is the definition recognized by the Federation Aeronautique Internationale and National Aeronautics and Space Administration.Full Answer >