Out-of-the-world discoveries.Astronomers Famous astronomers and astrophysicists include: Directory: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A
Astronomers say they may have found at least half of the universe's "missing mass." Since the 1930s, scientists have been looking for Looking for In the context of general equities, this describing a buy interest in which a dealer is asked to offer stock, often involving a capital commitment. Antithesis of in touch with. this invisible mass, also called "dark matter," which they say keeps galaxies from flying apart. (By their calculations, all the visible stars don't have enough mass, and therefore gravitational grav·i·ta·tion n. 1. Physics a. The natural phenomenon of attraction between physical objects with mass or energy. b. The act or process of moving under the influence of this attraction. 2. pull, to hold galaxies together.) How did astronomers find this dark matter? They detected increases in the brightness of stars in a nearby galaxy. This brightening, they say, could only be caused by large objects passing in front of the stars. The objects' mass indicates that they are white dwarfs white dwarf, in astronomy, a type of star that is abnormally faint for its white-hot temperature (see mass-luminosity relation). Typically, a white dwarf star has the mass of the sun and the radius of the earth but does not emit enough light or other radiation to be , or burned-out stars. If enough of these dead stars exist in space, they could make up half of the universe's missing mass. What about the other half? Scientists are still looking. TWO NEW PLANETS Those who hope to find life elsewhere in the universe have a couple of new places to look: two larger-than-Jupiter planets just discovered orbiting faraway far·a·way adj. 1. Very distant; remote. 2. Abstracted; dreamy: a faraway look. faraway Adjective 1. very distant 2. stars. Astronomers detected variations in the light coming from each star, which could be caused by a large planet in orbit. The stars, very similar to the Sun, are about 35 light-years away. (A light-year is the distance light travels in one year, about 9.5 trillion kilometers.) Based on the stars' brightness and their estimated distances from their planets, scientists think both planets may be warm enough for water to exist there. Since water is essential to life on Earth, the discovery prompts the question: Could these new planets harbor life? Stay tuned as scientists search for signs! BILLIONS OF NEW GALAXIES New photos from the Hubble Space Telescope Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the clearest view yet obtained of the universe. reveal that the universe may be a lot more crowded than scientists once thought. The photos, like this one, reveal some 1,500 galaxies (groups of stars like our Milky Way Milky Way, the galaxy of which the sun and solar system are a part, seen as a broad band of light arching across the night sky from horizon to horizon; if not blocked by the horizon, it would be seen as a circle around the entire sky. ) in a tiny speck of space. Based on their view of that speck, scientists now estimate there may be 50 billion galaxies in the universe - 5 times their previous estimate. With 50 to 100 billion stars in each galaxy, the universe may contain 5,000,000,000,000,000,000,000 stars - or about one trillion stars for every person on Earth! |
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