Sun questionsThis is a list of recently added questions about Sun.
What are coronal holes in the sun?
a sources of solar wind
a magnetic radiation sources
sources of cosmic heat
a craters of inactive volcanoes
Coronal holes generally discharge solar wind at a speed about twice the average. The escaping solar wind is known to travel along open magnetic field lines that pass through the coronal hole area. Since coronal holes are regions in the Sun’s corona that have much lower densities and temperatures than most of the corona, these regions are very thin. This thinness contributes to the solar wind since particles within the chromosphere can more easily break through.
How many percent of the total mass of the sun is gas?
By far most of the solar system's mass is in the Sun itself: somewhere between 99.8 and 99.9 percent. The rest is split between the planets and their satellites, and the comets and asteroids and the dust and gas surrounding our star.
What is an astronomical unit (AU)?
the distance of the Moon from Earth
the distance of the Earth from the Sun
the distance of the Moon to the Sun
None of the above
The astronomical unit (AU) represents the mean distance between the Earth and our sun. An AU is approximately 93 million miles (150 million km). It’s approximately 8 light-minutes.
What type of plasma is Sun composed of?
none of the above
The Sun is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. Hot plasmas (thermal plasmas) have electrons and the heavy particles at the same temperature, i.e. they are in thermal equilibrium with each other. Cold plasmas (nonthermal plasmas) on the other hand have the ions and neutrals at a much lower temperature, whereas electrons are much "hotter".
What is the visible surface of the Sun called?
The photosphere is a layer below which the Sun becomes opaque to visible light. It is tens to hundreds of kilometers thick, and is slightly less opaque than air on Earth. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon known as limb darkening.
In what period of time does the Sun make a full turn around the center of the Milky Way?
within every 225 million years
within 250 million years
within 300 million years
within 350 million years
The sun performs a full turn around the center of our galaxy during 225 million years.
The bright circle around the Sun seen in the picture is known as a halo. What causes it?
refraction of light in ice crystals
refraction in the lens of the eye or lens
refraction of light in water drops
reflections from the water surface
Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Among the best known halo types are the circular halo (properly called the 22° halo), Other common optical phenomena involving water droplets rather than ice crystals include the glory and the rainbow.
Which telescope was designed to detect exoplanets?
The Kepler Space Telescope
Space Chandra Telescope
The Hubble Space Telescope
Atacama Large Millimeter / submillimeter Array (ALMA)
Kepler is a space observatory launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March , 2009, in. Designed to survey a portion of our region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets,
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