Stars

One of the stars in the Big Dipper, named Mizar, has another star revolving around it. Each of those two stars have another star revolving around it, and Mizar and it's companion star each have another star revolving around them. So, what looks like one star is actually 6 stars. (Submitted 11/09/97 by Kelly-Anne & Barry Hollingshead)

• Lightening is 3 times hotter than the surface of the sun. The surface temperature of our sun is around 10,000 degrees Farenheit, while lightening is 30,000 degrees. (Submitted 07/13/97 by Dustin Smith)
• For North America the Earth is actually closer to the Sun in the Winter. (Submitted 07/08/97 by Brian Scully)
• Stars twinkle because the light we see coming from the stars travels through the atmosphere around the earth and there is turbulence in the Earth's atmosphere.
• If you were to drive a car at 100 kilometres an hour, 24 hours a day then you could reach the sun in about 3 years. (Submitted 07/03/97 by Viren Patel)
• If we could travel in a space ship at a speed of 50,000 kilometers per hour, it would take over 88,000 years to reach the star that is the nearest star of all to our sun, Proxima Centauri.
• It takes the light from the sun over eight (8) minutes to reach the Earth. That means that if the sun blew up right now, we would have eight more minutes of life before we were affected as well.
• The closest star besides our sun is Proxima Centauri, at a distance of 4.23 light years.
• To remember the types of star classifications, commit the phrase "Oh,Be A Fine Girl Kiss Me" to memory. The first letter of each word is astar classification: O,B,A,F,G,K,M.
• The umbra, or dark center, of a sunspot varies from just a feww hundred to over 50,000 miles across!
• The sun rotates on its axis about once a month.
• The photosphere of a star is the visible surface of that star. We do not recommend looking directly at the sun to verify this.
• The gasses in a sunspot average 3000F cooler than the rest of the sun.
• The diameter of the sun is roughly 860,000 miles.
• The density of the sun is 1 1/2 times that of water.
• The 11-year sunspot cycle is actually a part of a larger 22-year cycle in which the entire magnetic field of the sun may reverse itself!
• Our sun is moving at 12 miles-per-second towards the constellation Hercules.
• One pound of hydrogen being changed into helium inside a star yeilds energy equal to over 10,000 tons of coal.
• It is unsafe to look directly into the sun.
• If the sun were the size of the dot over a letter "i", the nearest star would be a dot 10 miles away.
• Every square yard of the sun's surface sends out enegery equal to the power of 700 automobiles. About one two-billionth of this energy actually reaches us.
• A pulsar is a neutron star that emits pulsed radio signals. The first pulsar was discovered in 1967.
• A protostar is a portion of a nebula that is about to form into a new star.
• A faculae is an area on the surface of a star that appears brighter by comparison to surrounding regions.
• A nova is a sudden increase in luminosity of a star, usually in the magnitide of thousands of times its original brightness. Stars that nova usually return to their original luminosity.
• Some stars are 600,000 times a bright as our sun.
• Of the 92 "natural" elements on Earth, 2/3 have been found in the sun. The rest are probably present as well.

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Mercury

• The evening star is actually a planet, usually Mercury or Venus, when seen in the western sky just after sunset.
• Mercury orbits the sun faster than any other planet, completing one revolution in 88 days.
• Mercury is the more dense than any object in the solar system, save Earth.
• It is suspected that 80 percent of Mercury's core is iron-nickel, as compared with Earth's 32 percent.
• Mercury has a very tenuous atmosphere composed of helium atoms captured from the solar wind.

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Venus

Venus is the hottest planet in the solar system, with temperatures reaching 860 degrees Fahrenheit! It is so hot, that it can melt lead! (submitted 12/7/97 by Jim Keesey.)

• The evening star is actually a planet, usually Mercury or Venus, when seen in the western sky just after sunset.
• Venus is often referred to as Earth's "sister-planet" because it comes very close to Earth in size and total mass.
• Venus has an extensive atmosphere with the high albedo of 76%, which completely covers and hides the surface.

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Earth / Moon

Our moon is moving away from the earth at about 3cm per year. (submitted 07/19/97 by cardys@ebtech.net.)

• There is enough railroad track on the Earth to go to the moon and back several times.
• The moon is approximately 234,000 miles from Earth.
• The moon's gravity is 1/6 that of the earth's. So if you weigh 160 pounds on earth, you would only weigh 26.6 pounds on the moon. (Submitted 07/13/97 by Dustin Smith)

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Mars

• The first pictures from the Mars Pathfinder mission, the first human presence on Mars in over 20 years, were black-and-white grainy photos received on 07/04/97.
• Evidence from the histroic Pathfinder mission to Mars suggests that at one time in Mars' ancient past, the surface of the planet was subject to massive flooding.
• The canals of Mars, now known to be an optical illusion, were once touted as evidence of extraterrestrial intelligence.
• The escape velocity of Mars is only 5.03 kilometers per second as compared with Earth's 11.2 kps escape velocity. Therefore, it requires much less energy to put an object in orbit from the surface of Mars than it does from Earth.
• The Martian "day" is only slightly longer than a day on Earth. On Mars, a day is 24 hours, 37 minutes, 23 seconds long whereas on Earth, a day is 23 hours 56 minutes, 04 seconds long.

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Jupiter

• Jupiter rotates about its axis in only 9 hours, 55 minutes, as compared with 23 hours, 56 minutes for Earth.
• The surface gravity of Jupiter is 2.6 times greater than Earth.

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Saturn

• Saturn has the lowest density of any other planet or satellite in the solar system.
• The surface gravity of Saturn is very close to Earth's. It is 1.159, compared to Earth's 1.0.

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Uranus

• Unlike Saturn and Jupiter, Uranus (and Neptune) evince no evidence of internal heating.
• Uranus is unique among the planets in that its equitorial plane is almost perpendicular to the orbital plane.

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Neptune

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Pluto

Due to it's strange orbit around the Sun, Pluto is closer to the Sun than Neptune between 1979 and 1999. (submitted 12/27/97 by Michael Chong.)

• Pluto has the largest comparative satellite in the solar system. Charon is nearly half as large as Pluto.

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Solar System

• Halley's Comet returns every 76 years.
• It is suspected that the asteroid belt, bewteen Mars and Jupiter, is composed of a planet that failed to form, or was broken apart, due to the gravitational influence of Jupiter.
• Our solar system extends close to 1/2 light years from the sun, to the suspected boundry of the Oort Cloud.
• There seems to be a good chance that there may be an as-yet undiscovered body at the edge of the solar system. This would help explain the perturbations in the orbits of Uranus and Neptune. Many suggestions have been made, but none verified as yet. Included among the possibilities are a new planet, a dark stellar companion, and even a black hole.

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Galaxy

• A globular cluster may contain over 10,000 stars across only 100 light-years.
• The Andromeda Galaxy (M31) is actually redshifted towards us. That means that the Milky Way and Andromeda are rushing towards each other.
• Quasars are the most distant objects in the known universe.
• If you could fly across our Galaxy from one side to the other at light speed, it would take 100,000 years to make the trip.

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Telescopes

• The formula for determining magnification is M= FT / FE where M = Magnification, FT - Focal Length of telescope, and FE = Focal Length of eyepiece. Be sure to convert all numbers to similar convention; metric or otherwise.
• The first telescope was put to practical use in 1609 by Galileo. It was a simple refractor.
• The 200-inch mirror for the telescope on Palomar Mountain weights over 14 tons and is 27-inches thick. The telescope gathers 640,000 times as much light as the human eye.
• Simple dobsonian telescopes are cheap, practical telescopes for beginner and intermediate observers. Meany seasoned observers also use large dobsonians. It is not uncommon to see a 32" dobsonian at a star party.

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Miscellaneous

• Plasma is an ionized gas.
• One parsec is equal to 19.2 million million miles.
• Astronomy is one of the few sciences where amtuers make actual and important contributions to the science.
• Astronomy is considered a "passive" science compared to most others becuase knowledge is based mostly upon observation rather than experimentation.
• Absolute Magnitude is the magnitude that any star would have if it were placed exactly 10 parsecs from the observer.

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