From Earth's surface, outer space begins at the somewhat-arbitrary Karman Line, or 100 km up, according to the Space website. From there, the observable universe stretches out without reaching any perceptible boundary.
As of 2014, the universe is 13.8 billion years old, Space reports. Given the speed of light, this places the farthest objects that can be seen from Earth as those that sit on that boundary. The universe is expanding, so objects at the extreme range of detection have since moved to a maximum distance of 48 billion light-years. Space goes on beyond that. If the universe has a flat curvature, which it very likely does, then space could be said to extend, literally, forever.Learn More
The universe has been known to be expanding since 1929, when Edwin Hubble measured the speed at which distant galaxies appear to be receding from Earth's position in space. In the early 21st century, astronomers measured the rate of expansion and discovered that it is increasing.Full Answer >
Aurora Borealis occurs when materials from the surface of the Sun collide with the atmosphere of the Earth. Experts make predictions about the occurrence of Aurora Borealis based on events taking place on the Sun and the speed of matter being thrown from the Sun's surface. Aurora Borealis is visible in portions of the Northern Hemisphere, including Canada, Scandinavia, North America, Siberia and Northern Europe.Full Answer >
In 2009, scientists at the University of Calgary used measurements of atmospheric wind and the flow of charged particles to determine that space begins at 73 miles above the Earth's surface. However, there are competing, and sometimes conflicting, assessments of Earth's boundaries.Full Answer >
According to the National Aeronautics and Space Administration, astronauts are sent into space to operate the International Space Station, help develop commercial spaceflight, investigate the possibilities of human exploration of deep space, develop new technologies and conduct research in a wide range of scientific fields. Many aspects of scientific studies of the Earth and the rest of the universe are easier to conduct from space.Full Answer >