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.
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
Scientists postulate that the end of the world could stem from a variety of sources, including destruction by meteor, overpopulation and war that affects the entire globe. Dysgenics, or the possible decay of human genes, nuclear warfare and climate change are other scenarios that scientists study and that may predict the end of the human species. Although some scenarios include the end of both the planet and the human race, others suggest that the planet and other forms of life are likely to continue to exist following the extinction of humans. A global pandemic, possibly due to a virus or an antibiotic-resistant bacteria, is thought to be the only cause of extinction that would affect humans alone.Full Answer >
By taking measurements of background microwave radiation, scientists have been able to establish that the average temperature of the universe is just over 2.7 degrees Kelvin. This means that the average temperature of space is just below negative 450 degrees Fahrenheit.Full Answer >
There is no definitive answer as to whether other universes exist, although many astronomers believe it is highly likely and have several theories on how or where they exist. Some people theorize that an infinite number of universes could have formed following the Big Bang, with each one having its own laws of physics.Full Answer >
The planetary system, containing Earth, is officially named the "Solar System," which consists of the Sun and its orbiting objects. PlanetsOfTheSolarSystem.net explains that the Sun does not have a scientific name, but is alternately called "Sol," based on Roman mythology. The name "Solar System" derives from the ancient Roman alternative.Full Answer >