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Explore the vastness of space from planets to galaxies, understanding distances in light-years and parsecs. Discover the immense scale of the universe using trigonometry and parallax. From the Heliosphere to the edge of the observable universe, marvel at the mind-boggling sizes and distances in outer space.
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Scale of the Universe This stuff is FAR!
Sizes of things • Earth diameter: 13,462 Km • Mars diameter: 6,800 Km • About ½ Earth • Jupiter diameter: 142,984 • 10+ times the Earth • 1,000+ Earths would fit inside • Sun diameter: 1.4 million kilometers • 109 times Earth, almost 10 times Jupiter • 1,000,000 Earths would fit inside
Distance to the Sun • Earth is 149,597,871 Km from the Sun • 92,955,807 miles • This distance is 1 astronomical unit • AU
Astronomical Unit • Mercury is .4 AU from the Sun • Venus is 0.72 AU • Mars is 1.52 AU • Jupiter is 5.2 AU • Saturn is 9.5 AU • Uranus is 19.6 AU • Neptune is 30 AU • Kuiper Belt is 30 to 50 AU • Oort Cloud is 50,000 to 100,000 AU!
Edge of the solar system • Heliosphere - The bubble in the interstellar medium of space caused by the Sun’s wind
Beyond the solar system • Beyond the solar system, the astronomical unit becomes too small • Like measuring distance around USA in millimeters • Need a bigger unit of measure – the Light Year (LY) • Light Year – distance light can travel in one year
Beyond the solar system • Oort Cloud is about 2 LY in diameter • Nearest star, Proxima Centauri, is 4.22 LY • Center of Milky Way is 26,000 LY • Milky way is 100,000 LY across • Nearest Galaxy, Andromeda, is 2.5 million LY away • Voyager 1 will take 18,000 years to go 1 LY
How do we know this? • Measurement to distant objects is done with trigonometry • Parallax - difference in the apparent position of an object viewed along two different lines of sight
Beyond the Light Year • Parsec – uses parallax • Parallax of 1 arcsecond • 3.26 LY • pc
Beyond the Light Year • Parsec is for really big distances • Proxima Centauri = 1.29 parsecs • Galaxy RXJ1242-11 = 200 million pc • Edge of observable universe 14 billion pc