Beyond Our Solar System: 10 Need-To-Know Things
- NASA
- Nov 20, 2017
- 2 min read
Expanding Universe Edwin Hubble discovered that the Universe is expanding and that at one point in time (14 billion years ago) the Universe was all collected in just one point of space. Billions and Billions There are believed to be at least a hundred billion galaxies in the Universe. A galaxy is full of stars: Our sun is just one of at least a hundred billion stars in our own Milky Way galaxy, and each of those stars could have their own planetary system. Small Matter Roughly 70 percent of the Universe is made of dark energy. Dark matter makes up about 25 percent. The rest -- everything on Earth, everything ever observed with all of our instruments, all normal matter adds up to less than 5 percent of the Universe. A Lot of Nothing We now know that our Universe has a "foamy" structure. The galaxies and clusters of galaxies that make up the visible universe are concentrated in a complex scaffold that surrounds a network of enormous empty spaces. Cosmic Neighborhood The Milky Way galaxy is in the Local Group, a neighborhood of about 30 galaxies. Our nearest major neighboring galaxy is called Andromeda. Extrasolar Planets There are thousands of planets around other stars in our galaxy and very likely around other stars in other galaxies within the Universe. Common Spiral Two-thirds of the galaxies within the Universe are similar to the Milky Way galaxy, in that they are spiral-shaped. The remaining third have elliptical shapes, and a few have unusual shapes like toothpicks or rings. Many Galaxies The Hubble Ultra Deep Field (HUDF), a space telescope, observed a tiny patch of sky (one-tenth the diameter of the moon) for one million seconds (11.6 days) and found approximately 10,000, of all sizes, shapes and colors. Is Anybody Out There? Scientists are searching for other planetary systems could have the potential for life. No Escape Fact: Black holes are not empty spaces in the Universe. A black hole is a great amount of matter packed into a very small area, which results in a gravitational field so strong that nothing -- not even light -- can escape.