Astronomy — Fascinating facts
- Except for the widely scattered stars and a few atoms of gas drifting between the stars, the universe is nearly empty.
- The thin gas that fills interstellar space is thinner than the best vacuums on earth.
- Everything in the universe is assembled out of three things: protons, neutrons, and electrons.
- A marshmallow dropped onto a neutron star from a distance of one astronomical unit (1 AU) would hit with the impact equivalent to a 3-megaton nuclear warhead.
- Because of the great distance between stars, a collision between 2 stars is about as likely as a collision between 2 gnats flitting about at random in a football stadium.
- How big is an electron? An electron is to a grain of sand as the grain of sand is to our Earth.
- How small is the charge of an electron? It takes a flow on one million trillion electrons per second to light a 10-watt bulb.
- How empty is an atom? If the outer electron shell of an atom was compared to the Astrodome, the nucleus would be a golf ball in the center of the stadium.
- If most of an atom is empty space, why do objects feel hard when we touch them? The surface of objects, including our fingers, are walls of electrons. When surfaces meet, strong electrical repulsion occurs.
- There are a trillion trillion atoms in a cubic inch of ordinary solid material, or roughly the number of grains of sand in all the oceans of Earth.
- The nuclear force holds protons and neutrons together with such force that the resultant density is one billion tons per cubic inch.
- Household plastic wrap is 100,000 atoms thick, and the nucleus of the atoms is 100,000 times smaller than the atom itself.
- We bind weak Balmer lines in the spectra of very cool stars (5000 degrees Kelvin) and very hot stars (20,000 degrees Kelvin), meaning that there are few electrons in the second energy level. Medium temperature stars (10,000 degrees Kelvin) have strong Balmer lines (many electrons in the second energy level).
- The star nearest our Sun, Proxima Centauri, is 4.2 light-years away.
- The Andromeda Galaxy is 2 million light-years away and 150,000 light years in diameter.
- Betelguese (the red giant star in the constellation Orion) is 432 million miles in diameter, and 520 light-years away. If placed in the center of our solar system, it would extend out to the orbit of Jupiter. The same can be said for Antares, the red giant in the constellation Scorpius.
- The Eagle Nebula is 20 light-years in diameter and 6000 light-years away.
- The Lagoon Nebula in Sagittarius is a cloud of gas and dust 60 light-years in diameter. Its gases are excited by the UV radiation of the hot young stars within it.
- Pluto’s orbit is so elliptical that Pluto can be closer to the Sun than Neptune.
- Why is the sky blue? The Sun’s brilliance makes Earth’s atmosphere glow with scattered light. Blue light scatters off air molecules slightly better than red light, so we see the sky filled with blue light bouncing in all directions.
- The Sun contains 1057 atoms.
- The average American is 6-times more-likely to be killed by an asteroid impact than in an airplane crash.
- Our Sun generates 6 x 1013 more energy per second than all the coal, oil, natural gas, and nuclear power plants on Earth combined.
- It takes 1 million years for the average photon to travel from the Sun’s center to the surface of the Sun.
- The escape velocity for an object on Earth’s surface is 25,000 mph.
- The following statement was made in ‘Sky and Telescope’ magazine in 2003: “A planet for nearly every star? Astronomers in 8 programs around the world have been monitoring about 1,800 Sun-like stars for tiny redial-velocity wobbles caused by orbiting planets. By this method, they have found about 116 planets orbiting 101 stars. On the face of it, this means that at least 5 percent of Sun-like stars have planets.” Due to various factors, however, astronomers have concluded that the 5% estimate is a lower limit to the true fraction of Sun-like stars with planets, which may be as large as about 100 percent.
- The Keck telescope system on the summit of Mauna Kea in Hawaii is so powerful that it could resolve the two separate headlights of a car at a distance of 16,600 miles!
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