Universe

A:

The apparent brightness of a star viewed from Earth varies based both on the type of star and its distance from the planet. The apparent magnitude differs from a star's absolute magnitude, which describes its brightness from a set distance, rather than the varying distances of stars seen from Earth. The lower the apparent magnitude, the brighter the star is as seen from Earth.

See Full Answer
Filed Under:
  • What are some facts about the Aurora Borealis?

    Q: What are some facts about the Aurora Borealis?

    A: 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.
    See Full Answer
    Filed Under:
  • What is the temperature of a black hole?

    Q: What is the temperature of a black hole?

    A: According to NASA, the temperature of a black hole with the mass of the sun is only one ten-millionth of a degree over absolute zero. Scientists determine this by measuring the temperature of the radiation that comes from a black hole.
    See Full Answer
    Filed Under:
  • Do the planets travel around the sun in a path called an orbit?

    Q: Do the planets travel around the sun in a path called an orbit?

    A: Planets travel around the sun in paths called orbits. Each planet has its own orbit around the sun, and one orbit around the sun is called a year. All planets travel in the same direction around the sun.
    See Full Answer
    Filed Under:
  • What happens after a supernova?

    Q: What happens after a supernova?

    A: Depending on the size of the star before it explodes as a supernova, the core of the star either shrinks back into a tiny neutron star or becomes a black hole. If the star is only a few times bigger than the sun, the core becomes a tiny neutron star. If the star is much bigger than the sun, the chances of it becoming a black hole are much greater.
    See Full Answer
    Filed Under:
  • Who discovered the planet Saturn?

    Q: Who discovered the planet Saturn?

    A: It is impossible to determine who discovered Saturn, as it is one of five planets that are visible without the aid of instruments. Saturn has been widely observed by people for thousands of years, although its unique and complex system of rings are only visible using a telescope.
    See Full Answer
    Filed Under:
  • Why do some stars appear brighter than others?

    Q: Why do some stars appear brighter than others?

    A: The apparent brightness of a star viewed from Earth varies based both on the type of star and its distance from the planet. The apparent magnitude differs from a star's absolute magnitude, which describes its brightness from a set distance, rather than the varying distances of stars seen from Earth. The lower the apparent magnitude, the brighter the star is as seen from Earth.
    See Full Answer
    Filed Under:
  • Why did people once believe that Earth was the center of the Universe?

    Q: Why did people once believe that Earth was the center of the Universe?

    A: The belief of early astronomers that the Earth was the center of the universe stemmed from limited astronomical tools and geocentric attitudes. The Ptolemaic Model, developed around 100 A.D., presented the Earth-centered solar system in which most early Roman astronomers believed.
    See Full Answer
    Filed Under:
  • How many modern constellations are there?

    Q: How many modern constellations are there?

    A: As of 2014, there are 41 modern constellations, which are constellations added to the catalogue after 1600. Four of them, Carina, Puppis, Pyxis and Vela are derived from Argo, a constellation catalogued by Ptolemy.
    See Full Answer
    Filed Under:
  • Q: How many extrasolar planets have been discovered so far?

    A: About 1,700 extrasolar planets have been discovered so far, including 715 discoveries that were announced in February, 2014 by the National Aeronautical and Space Administration. The newest extrasolar planets were discovered when astronomers examined 305 stars with Kepler, NASA's first extrasolar planet mission. Extrasolar planets, also called exoplanets, are planets that exist outside of the solar system.
    See Full Answer
    Filed Under:
  • Q: Did the idea of a heliocentric view of the solar system originate with Copernicus?

    A: The ancient Greek astronomer and mathematician known as Aristarchus of Samos was the first person to propose a heliocentric view of the solar system. He lived circa 310 B.C. to 230 B.C. and stated that the Earth, like other planets, orbited the sun, which he regarded as the universe's center.
    See Full Answer
    Filed Under:
  • Q: How does gravity affect the Earth?

    A: An important effect of gravity on the Earth is that the sun's gravity is responsible for the Earth's regular orbit through the solar system. The Earth travels at a velocity that approximates the force the sun exerts on the planet, resulting in a regular orbit. Without gravity, the planet would spin away into space, and if gravity was suddenly increased, it would eventually spiral into the star's fiery surface.
    See Full Answer
    Filed Under:
  • Q: How do you make a model of a solar system?

    A: One of the easiest ways to make a model of a solar system is to cut circles from cardboard to represent the planets and hang them in orbits from a larger circle. Use nine circles to represent the eight planets and the sun.
    See Full Answer
    Filed Under:
  • Q: What is believed to be the origin of giant elliptical galaxies?

    A: Giant elliptical galaxies form early in the life of local galactic clusters as members of the group pass close by each other and begin to merge, according to John Dubinski for the Canadian Institute for Theoretical Astrophysics. In any sizable galactic cluster, some galaxies near the core of the group gravitationally interact with each other, exchange material and eventually fall together to form the core of the central elliptical giant.
    See Full Answer
    Filed Under:
  • Q: How big is space?

    A: 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.
    See Full Answer
    Filed Under:
  • Q: What are the differences between the solar system and the Milky Way Galaxy?

    A: The solar system is a system in the universe that is comprised of the Sun, eight official planets, three dwarf planets and approximately 130 satellites of the planets, according to Nine Planets. Besides these bodies, the solar system also has numerous comets and asteroids, which are smaller. On the other hand, the Milky Way is the galaxy within which the solar system falls.
    See Full Answer
    Filed Under:
  • Q: How did the universe begin?

    A: The universe began with the Big Bang around 13.6 billion years ago. The Big Bang was a rapid expansion of the universe from a tiny single point. This hot expansion has continued since then, resulting in the expansion of the universe in every direction.
    See Full Answer
    Filed Under:
  • Q: What is the Friedmann universe theory?

    A: In 1922, Russian mathematician Alexander Friedmann answered Albert Einstein's equations of general relativity. Friedmann's answers led to the theory that the universe is dynamic, meaning that it changes in size over time. Friedmann introduced the term "expanding universe" into the scientific lexicon.
    See Full Answer
    Filed Under:
  • Q: Why is outer space dark?

    A: Outer space appears dark at night for multiple reasons, the most simple being that the nearest light source, the sun, is blocked by the earth, creating darkness. Outside Earth's atmosphere, outer space appears dark instead of blue because the sun's light is not refracted by atmospheric gases.
    See Full Answer
    Filed Under:
  • Q: What is the ultimate fate of an open universe?

    A: 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.
    See Full Answer
    Filed Under:
  • Q: How did the Milky Way get its name?

    A: The Milky Way's name stems from the Greeks, who referred to the galaxy as galaxias kyklos, or milky circle. The Romans, who called it via lactea, or "the road of milk," altered the term from its original Greek origins.
    See Full Answer
    Filed Under:
  • What is our solar system called?

    Q: What is our solar system called?

    A: 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.
    See Full Answer
    Filed Under: