Cosmology and astronomy | Science | Khan AcademySwitch to English sign up. Phone or email. Don't remember me. Devilcharlie Nguyn. All posts 7, Devilcharlie Nguyn pinned post 24 May Denis Shelekhov Jan 14, at pm.
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Login or register for a free account to access and create wishlists! SciGuides are a collection of thematically aligned lesson plans, simulations, and web-based resources for teachers to use with their students centered on standards-aligned science concepts. A solar system consists of at least one central star in our case, the Sun and other solar system objects e. Stars and their solar systems are further held together in galaxies. Our own galaxy, known as the Milky Way, has over billion stars, and we are only beginning to identify other solar systems in the Milky Way.
Universe, Eleventh Edition (), Astronomy: The Solar System and 7 SEVENTH EDITION .. galaxies and planets orbiting distant stars.
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Outer space , or simply space , is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum containing a low density of particles, predominantly a plasma of hydrogen and helium , as well as electromagnetic radiation , magnetic fields , neutrinos , dust , and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang , is 2. Outer space does not begin at a definite altitude above the Earth's surface. The framework for international space law was established by the Outer Space Treaty , which entered into force on 10 October This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space.
A fewer than a thousand B a few thousand C about ten thousand D about a hundred thousand E more than you could count in your lifetime Answer: B 2 Which of the following best describes the modern definition of a constellation? A a region of the celestial sphere B a pattern of bright stars in the sky C a Greek mythological figure D a collection of stars that are near one another in space E a group of stars that all lie at about the same distance from Earth Answer: A 3 Which of the following statements about the celestial sphere is not true? A When we look in the sky, the stars all appear to be located on the celestial sphere. B Earth is placed at the center of the celestial sphere. C The celestial sphere does not exist physically. D The "celestial sphere" is just another name for our universe. E From any location on Earth, we can see only half the celestial sphere at any one time.