Astronomy

A:

There are between 30 and 54 known galaxies in the local group to which the Milky Way belongs. Some astronomers include dwarf galaxies in this number.

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  • What is the circle of illumination?

    Q: What is the circle of illumination?

    A: The circle of illumination is the line that separates the Earth to create equal parts of day and night. It passes through the poles and allows the entire Earth to have an equal amount of time spent during the daylight and nighttime hours.
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  • What is the farthest star from Earth?

    Q: What is the farthest star from Earth?

    A: Scientists will never know the farthest star from Earth, as the star is so far away that its light has not, nor will ever, have enough time to reach Earth. Even the stars within the visible universe are far too numerous to count, but the farthest one that humans have ever detected is about 55 million light years away. This incredibly distant star is called SDSS J 122952.66 +112227.8.
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  • How do I set up a Tasco telescope?

    Q: How do I set up a Tasco telescope?

    A: Tasco provides free online instruction manuals for all of their products. Their telescopes come partially assembled. The tripod needs to be assembled, then the main body of the telescope attached to it. Once the main body of the telescope is on the tripod, the various accessories such as finderscopes and eyepieces need to be attached. The accessories vary slightly by model of telescope.
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  • How does gravity keep us on Earth?

    Q: How does gravity keep us on Earth?

    A: Gravity is one of the fundamental forces of the universe, and it keeps us on Earth because it is relentlessly attractive. Every massive particle exhibits gravity by pulling closer to every other particle. The strength of this interaction is dependent on two quantities: the amount of mass and the distance between objects. It is possible to escape Earth's gravity if you have enough energy to speed up sufficiently.
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  • Who named the Milky Way?

    Q: Who named the Milky Way?

    A: Early Greek astronomers named the galaxy "Via Lactea" in reference to the pale band of light formed by stars along the galactic plane. The origin of the name, which translates as "Road of Milk," has been lost to time.
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  • What is a shooting star?

    Q: What is a shooting star?

    A: Although a shooting star looks like a star shooting across the sky, it's actually a meteor, or small rock that hits Earth's atmosphere. Because of the speed at which the meteor, or meteoroid, is traveling it burns and releases a glow.
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  • What is the sky made of?

    Q: What is the sky made of?

    A: Four layers of the earth's atmosphere containing various gases make up the composition of the sky. The layers of the atmosphere are divided into the troposphere, the stratosphere, the mesosphere and the thermosphere. The atmosphere's divisions occur according to temperature fluctuations.
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  • Is the sun bigger than the moon and Earth?

    Q: Is the sun bigger than the moon and Earth?

    A: The sun is bigger than both the moon and the Earth. The Earth is approximately 7,926 miles in diameter, while the sun is roughly 900,000 miles in diameter. The moon is smaller than both the sun and the Earth, with a diameter of 2,159.26 miles.
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  • Why is it that stars twinkle but planets do not?

    Q: Why is it that stars twinkle but planets do not?

    A: Stars twinkle because they are point light sources. Passing through the atmosphere, the small beam of light constantly shifts by bouncing off particles in the air. Planets are closer, so they appear as discs, with the shifting of light from one side cancelling out the other.
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  • Are stars bigger than the sun?

    Q: Are stars bigger than the sun?

    A: Stars exist that are both bigger and smaller than the sun. The sun has a radius of 1.4 million kilometers and, relative to other stars, is an average size.
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  • What is terrestrial navigation?

    Q: What is terrestrial navigation?

    A: Terrestrial navigation is a field of study that helps sea-faring people locate points at sea and on the land. Similarly, it involves being able to identify the position of the ship anywhere in the world. Students are instructed in the use of nautical charts, compass corrections and voyage planning.
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  • What is the weather like on Uranus?

    Q: What is the weather like on Uranus?

    A: With an atmospheric temperature of -224 degrees Celsius and a surface temperature of -197 degrees Celsius, Uranus is a very cold planet with strong winds. It is the coldest planet in the solar system.
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  • Why do stars pulsate?

    Q: Why do stars pulsate?

    A: Stars appear to pulsate and twinkle in the night sky due to the refraction of light through the Earth's atmosphere. When the light from a star enters the atmosphere, air molecules bounce and deflect the light rays, slightly altering the apparent position and intensity of the star.
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  • What is outer space made of?

    Q: What is outer space made of?

    A: Outer space contains a low density of particles, primarily hydrogen gas, along with electromagnetic radiation. Many people, however, mistakenly believe outer space is a complete vacuum. The term "outer space" is used mainly to distinguish the space between planets from the planets and their airspace.
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  • How many times bigger is the sun than the earth?

    Q: How many times bigger is the sun than the earth?

    A: According to NASA, the sun’s diameter is approximately 100 times larger than the diameter of the earth. The earth would have to be lined up 100 times in order to stretch across the face of the sun.
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  • How would you describe a solar eclipse?

    Q: How would you describe a solar eclipse?

    A: A solar eclipse occurs when the moon moves directly between the Earth and the sun. The moon's shadow travels over the surface of the Earth and blocks out the light from the sun seen on Earth.
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  • How long will the sun last?

    Q: How long will the sun last?

    A: The sun will last approximately another five billion years, according to NASA in 2012. The sun's light and heat are generated by the burning, or fusing, of hydrogen gas into helium gas.
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  • What are some solar system project ideas?

    Q: What are some solar system project ideas?

    A: A popular solar system project idea is the construction of a solar system model. While the hanging Styrofoam ball model is an easy-to-create option, constructing the solar system in panoramic form in a shoe box can also be fun.
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  • What is a planetarium?

    Q: What is a planetarium?

    A: A planetarium is a facility designed to replicate the features of the universe in the night sky. Similar to a museum or science center, planetariums are developed in communities to offer education and entertainment to people curious about the field of astronomy. Visitors typically pay admission fees to enter just as they would at a theater or zoo.
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  • How do space craters get their names?

    Q: How do space craters get their names?

    A: The International Astronomical Union (IAU), an organization of astronomers, names the craters on planets and moons in the solar system by giving each planet a creative theme. For example, the moon’s craters are usually named for deceased explorers, scientists and scholars, while large craters on Venus are named for famous women in various professional fields.
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  • What is the difference between equinox and solstice?

    Q: What is the difference between equinox and solstice?

    A: A solstice is defined as the point during the Earth's orbit around the sun at which the sun is at its greatest distance from the celestial equator, while an equinox is at its least distance. A solstice is characterized by either an extremely long night or an extremely short day.
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