GK
THE UNIVERSE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The distance across the Milky Way galaxy.
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The distance to the nearest star.
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The distance across the solar system.
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The distance to the nearest galaxy.
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Detailed explanation-1: -The closest known galaxy to us is the Canis Major Dwarf Galaxy, at 236, 000, 000, 000, 000, 000 km (25, 000 light years) from the Sun.
Detailed explanation-2: -The Milky Way is about 1, 000, 000, 000, 000, 000, 000 km (about 100, 000 light years or about 30 kpc) across. The Sun does not lie near the center of our Galaxy. It lies about 8 kpc from the center on what is known as the Orion Arm of the Milky Way.
Detailed explanation-3: -The answer is GN-z11 (Oesch et al. 2016) which has a redshift of z=11.09. This corresponds to a distance of d=32.2Glyr (i.e. billion light-years), and hence, by Hubble’s law, to a recession velocity of v=H0d=670000kms−1, or more than twice the speed of light.
Detailed explanation-4: -Astronomers can use what are called surface brightness fluctuations (SBF, for short), along with the color of a galaxy, to calculate how far away it is from earth. Most galaxies measured in this way are millions of light years away.