Space Dimensions & Planetary Facts

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Earth is 5 billion years old and 7,926 miles in diameter

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Estimated age of the universe =  14 – 16 billion years old

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10 million trillion atoms in one cc of air at sea level

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1 atom per cc in the void between stars

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1 atom per cc in the void between galaxies

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Distance to moon = 238,774 miles

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Distance to sun 93,150,000 miles = 1 AU

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Distance to Pluto’s orbit varies from 26 – 52 AU

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Distance to nearest star (Alpha Centauri) is 4.3 LY

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1 LY = 65,555 AU

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Speed of light = 186,170 miles per second

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1 AU = 8 minutes at Speed of Light

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Light travels in 1 light year 5.9 trillion miles

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Milky Way galaxy is 90,000 LY wide and 3,000 LY thick

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Estimated number of stars in the Milky Way Galaxy = 400 billion +

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Estimated number of stars in the universe = 5 billion trillion

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Estimated number of galaxies in the universe = 50 billion +

 

Drake Equation

Is there a way to estimate the number of technologically advanced civilizations that might exist in our Galaxy?  While working at the National Radio Astronomy Observatory in Green Bank, West Virginia, Dr. Frank Drake conceived a means to mathematically estimate the number of worlds that might harbor beings with technology sufficient to communicate across the vast gulfs of interstellar space.  The Drake Equation, as it came to be known, was formulated in 1961 and is generally accepted by the scientific community.

N = R* fp ne fl fi fc L

 

Where...

N = number of communicative civilizations
R* = rate of formation of suitable stars (stars such as our Sun)
fp = fraction of those stars with planets (current evidence indicates that planetary systems may be common for stars like the Sun.)
ne = number of Earth-like worlds per planetary system
fl = fraction of those Earth-like planets where life actually develops
fi = fraction of life sites where intelligence develops
fc = fraction of communicative planets (those on which electromagnetic communications technology develops)
L = "lifetime" of communicating civilizations

 

Dr. Frank Drake's own current solution to the Drake Equation estimates 10,000 communicative civilizations in the Milky Way.

The famous Drake Equation, which purports to estimate the number of communicative civilizations in the Galaxy, was actually the agenda for the world's first SETI meeting in 1961.  This plaque now graces the very wall

of the room at NRAO Green Bank, WV, which once held the blackboard

on which the equation was first written.

Planetary Facts & Figures

 

Planet Symbol

Planet Surface

Mercury, the planet closest to the Sun, has almost no atmosphere and its dusty surface of craters resembles the Moon.  The planet was named for the Roman god Mercury, a winged messenger, because it travels through the sky quickly.  In fact, it travels around the Sun faster than any other planet.  Mercury is difficult to see from Earth because of the glare from the sun.  Nicolaus Copernicus, for all his years of research and observation, never once was able to see Mercury.
bulletSize: two-fifths the size of Earth; second smallest in the solar system.
bulletDiameter: 3,032.4 miles (4,880 km).
bulletSurface: covered by a dusty layer of minerals (silicates), the surface is made up of plains, cliffs, and craters.
bulletAtmosphere: a thin mixture of helium (95%) and hydrogen.
bulletTemperature: Mercury alternately bakes and freezes, depending on what side is lit by the Sun. The sunlit side can reach up to 950° F (510° C) and the dark side can drop as low as –346° F (–210° C).
bulletRotation of its axis: 59 Earth days.
bulletRotation around the Sun: 88 Earth days.
bulletYour weight: if you weigh 100 pounds on Earth, you would weigh 38 pounds on Mercury.
bulletDistance from Earth: 57 million miles, at the closest point in its orbit.
bulletMean Distance from Sun: 36 million miles (57.9 million km).
bulletSatellites: 0
bulletRings: 0
 

Planet Symbol

Global View

Volcanoes

Venus is often called Earth's twin because the two planets are close in size but that's the only similarity.  The thick clouds that cover Venus create a greenhouse effect that keeps it sizzling at 864°F.  Venus, named after the Roman goddess of love and beauty, is also known as the “morning star” and “evening star” since it is visible at these times to the unaided eye.  Venus appears as a bright, white disk from Earth.
bulletSize: about 650 miles smaller in diameter than Earth.
bulletDiameter: 7,519 miles (12,100 km).
bulletSurface: a rocky, dusty, waterless expanse of mountains, canyons, and plains, with a 200-mile river of hardened lava.
bulletAtmosphere: carbon dioxide (95%), nitrogen, sulfuric acid, and traces of other elements.
bulletTemperature: ranges from 55°F (13°C) to 396°F (202°C) at the surface.
bulletRotation of its axis: 243 Earth days.
bulletRotation around the Sun: 225 Earth days.
bulletYour weight: if you weigh 100 pounds on Earth, you would weigh 88 pounds on Venus.
bulletDistance from Earth: at its closest, Venus is 26 million miles (41,840,000 km) away.
bulletMean Distance from Sun: 67.24 million miles (108.2 million km).
bulletSatellites: 0
bulletRings: 0
 

Planet Symbol

Global View

Earth is not perfectly round as it bulges at the equator and is flatter at the poles.  From space the planet looks blue with white swirls, created by water and clouds.  Only planet known to have life.
bulletSize: four planets in our solar system are larger and four are smaller than Earth.
bulletDiameter: 7,926.2 miles (12,756 km).
bulletSurface: Earth is made up of water (70%), air and solid ground.  It appears to be the only planet with water.
bulletAtmosphere: nitrogen (78%), oxygen (21%), other gases.
bulletRotation of its axis: 23 hours, 56 minutes, 4 seconds.
bulletRotation around the Sun: 365.2 days.
bulletMean Distance from Sun: 92.9 million miles (149.6 million km).
bulletSatellites: 1
bulletRings: 0
 

Planet Symbol

Global View

Largest volcano in Solar System

Because of its blood-red color (which comes from iron-rich dust), this planet was named for Mars, the Roman god of war.  Mars is the fourth planet from the Sun, situated between Earth and Jupiter.  Three-quarters red, Mars also has dark blotches on it and white areas at the poles (which are polar ice caps made of frozen water/carbon dioxide.)
bulletSize: about one-quarter the size of Earth.
bulletDiameter: 4,194 miles (6,794 km).
bulletSurface: canyons, dunes, volcanoes and polar caps of water ice and carbon dioxide ice.
bulletAtmosphere: carbon dioxide (95%).
bulletTemperature: as low as –305°F (–187°C).
bulletRotation of its axis: 24 Earth hours, 37 minutes, 23 seconds.
bulletRotation around the Sun: 687 Earth days.
bulletYour weight: if you weigh 100 pounds on Earth, you would weigh 38 pounds on Mars.
bulletDistance from Earth: 35 million miles (56 million km) at the closest point in its orbit.
bulletMean Distance from Sun: 141.71 million miles (227.9 million km).
bulletSatellites: 2
bulletRings: 0
 

Gaspra

 

Asteroids are small bodies that are believed to be left over from the beginning of the solar system 4.6 billion years ago.  They are rocky objects with round or irregular shapes up to several hundred km across, but most are much smaller.  More than 100,000 asteroids lie in a belt between Mars and Jupiter.  These asteroids lie in a location in the solar system where there seems to be a jump in the spacing between the planets.  Scientists believe the Asteroid Belt is either an unformed planet or a planet that was broken apart due to the gravity of Jupiter or by a large impact.
 

Planet Symbol

Jupiter & Ganymede

Io, in eclipse

Jupiter, the largest planet in our solar system, was named for the most important Roman god because of its size.  About 1,300 Earths would fit into the planet.  Viewed through a large telescope, Jupiter is stunningly colorful—it is a disk covered with bands of blue, brown, pink, red, orange and yellow.  Its most distinguishing feature is “the Great Red Spot,” an intense windstorm larger in size than the Earth, which has continued for centuries without any signs of dying down.
bulletSize: 11 times the diameter of Earth.
bulletDiameter: 88,736 miles (142,800 km).
bulletSurface: a hot ball of gas and liquid.
bulletAtmosphere: whirling clouds of colored dust, hydrogen, helium, methane, water and ammonia. The Great Red Spot is an intense windstorm larger than Earth.  There is evidence that the Great Red Spot is getting smaller.
bulletTemperature: –234°F (–148°C) average.
bulletRotation of its axis: 9 hours and 55 minutes.
bulletRotation around the Sun: 12 Earth years.
bulletYour weight: if you weigh 100 pounds on Earth, you would weigh 265 pounds on Jupiter.
bulletDistance from Earth: at its closest, 370 million miles (591 million km).
bulletMean Distance from Sun: 483.88 million miles (778.3 million km).
bulletSatellites: 63 (as of November 2007)
bulletRings: Yes (4)
 

Planet Symbol

Cassini spacecraft during flyby of Saturn

Saturn, the second-largest planet, has majestic rings surrounding the planet.  Named for the Roman god of farming, Saturn was the farthest planet known by the ancients.  Saturn's rings are flat and lie inside one another. They are made of billions of ice particles and rock.  Saturn is of such low density that if you could place the planet in a bathtub, (imagine the size!), it would float!
bulletSize: about 10 times larger than Earth.
bulletDiameter: 74,978 miles (120,660 km).
bulletSurface: liquid and gas.
bulletAtmosphere: hydrogen and helium.
bulletTemperature: –288°F (–178°C).
bulletRotation of its axis: 10 hours, 40 min, 24 sec.
bulletRotation around the Sun: 29.5 Earth years.
bulletYour weight: if you weigh 100 pounds on Earth, you would weigh 107 pounds on Saturn.
bulletDistance from Earth: 744 million miles at the closest point.
bulletMean Distance from Sun: 887.14 million miles (1,427 million km).
bulletSatellites: 60 (as of November 2007)
bulletRings: 1,000+
 

Planetary Symbol

Global View

Uranus is a greenish-blue planet, twice as far from the Sun as its neighbor Saturn.  Uranus wasn't discovered until 1781.  It's discoverer, William Herschel, named it Georgium Sidus (the Georgian star) after the English king, George III.  Later its name was changed to Uranus, after an ancient Greek sky god, since all the other planets had been named after Roman and Greek gods.
bulletSize: 4 times larger than Earth.
bulletDiameter: 32,193 miles (51,810 km).
bulletSurface: little is known.
bulletAtmosphere: hydrogen, helium, and methane.
bulletTemperature: uniform temperature of –353°F (–214°C).
bulletRotation of its axis: 17 hours.
bulletRotation around the Sun: 30,685 days or 84 Earth years.
bulletYour weight: not known.
bulletDistance from Earth: at the closest point 1,607,000 miles.
bulletMean Distance from Sun: 1,783.98 million miles (2,870 million km).
bulletSatellites: 27 (as of November 2007)
bulletRings: 11
 

Planet Symbol

Global View showing "Great Blue Spot."  This spot has disappeared and reappeared indicating that storms form and dissipate similar to weather systems on Earth.

Neptune, named for an ancient Roman sea god, is a stormy blue planet about 30 times farther from the Sun than Earth.  Neptune was discovered when astronomers realized that something was exerting a gravitational pull on Uranus and that it was possible that an unknown planet might be responsible.  Through mathematical calculations, astronomers determined there was indeed an undiscovered planet out in space—a year before it was actually seen for the first time through a telescope (in 1846).
bulletSize: about 4 times the size of Earth.
bulletDiameter: 30,775 miles (49,528 km).
bulletSurface: a liquid layer covered with thick clouds and with constant, raging storms.
bulletAtmosphere: hydrogen, helium, methane and ammonia.
bulletTemperature: –353°F (–214°C).
bulletRotation of its axis: 16 hours and 7 minutes.
bulletRotation around the Sun: 165 Earth years.
bulletYour weight: not known.
bulletDistance from Earth: 2,680,000,000 miles at closest point.
bulletMean Distance from Sun: 2,796.46 million miles (4,497 million km).
bulletSatellites: 13 (as of November 2007)
bulletRings: 4
 

Planet Symbol

Pluto & Charon

Pluto & Charon as seen by the Hubble telescope

Pluto, named after the Roman and Greek god of the underworld, is the coldest, smallest and outermost body in our solar system.  Pluto has been demoted as a full planet and is now referred to as a "plutonian" or "dwarf planet."  Pluto and its moon, Charon, are called "double planets" because Charon is so large it seems less of a moon than another planet.  Pluto was predicted to exist in 1905 and discovered in 1930.  It is the only solar system body that has not yet been studied closely by a space probe.  This will change with the New Horizons Mission which will reach Pluto in July of 2015.  During each revolution around the sun, Pluto passes inside Neptune's orbit for 20 years, making Neptune the outermost planet for that time.  Pluto passed inside Neptune's orbit in 1979 and remained there until 1999.  It will not return to that position until 2227.
bulletSize: less than one-fifth the size of Earth.
bulletDiameter: 1,423 miles? (2,290 km?).
bulletSurface: a giant snowball of methane and water mixed with rock.
bulletAtmosphere: methane.
bulletTemperature: between - 369°F and - 387°F (- 223°C and - 233°C).
bulletRotation of its axis: 6 days, 9 hours, 18 minutes.
bulletRotation around the Sun: 248 Earth years.
bulletYour weight: not known.
bulletDistance from Earth: at the closest point, 2.67 billion miles.
bulletMean Distance from Sun: 3,666 million miles (5,900 million km).
bulletSatellites: 3 (as of November 2007)
bulletRings: ?

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