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.Know More
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 >
During the Space Race fervor of the mid-1900s, humans from several different countries sent a number of non-human animals into space, including a cat who flew a successful French space mission in 1963, parachuting safely back to earth at the end of her trip. According to NASA, this cat, named Félicette, made the first successful feline trip into space on a Veronique AGI sounding rocket No. 47. Her French cat astronaut successor, an unnamed cat, was not able to be recovered and died during the mission, which took place just a few days after Félicette made her groundbreaking trip.Full Answer >
Sound is unable to travel through truly empty space. The phenomenon known as sound is the perception of alternating waves of compression passing through a medium. Unlike light, which is able to propagate without a medium, sound waves must have a medium, such as air, water or rock, to carry them.Full Answer >
Although the ultimate fate of the universe is a largely debated topic, according to the University of Tennessee, in an open universe the universe will continue to expand forever. This is due to insufficient mass to cause the expansion to stop.Full Answer >