Astronomical
Quick Facts
Few interesting facts that show the
mind boggling distances and figures of space and astronomy.
- One astronomical unit (a.u.) = 149.6 million km or 92.9
million miles
- Our Sun sheds 100 Million Tons of matter per second
- One light year = 5.88 trillion miles, 9.5 trillion km, or
63,000 a.u.
- One parsec = 3.26 light-years
- Andromeda Galaxy, the nearest large galaxy beyond our own
Milky Way is 2.5 million light-years distant
- Magnitude is the standard to measure apparent brightness
of objects - lower the number, the brighter the object
- Magnitude 6.0 is the faintest stars visible to the
unaided human eye detect limit
- Magnitude 9.0 is 80 times dimmer than the human eye can
detect
- Magnitude 19.5 is 250,000 times dimmer than the human eye
can detect
- Magnitude 20.0 is 1,000,000 times dimmer than the human
eye can detect
- Negative numbers are reserved for the most brilliant
objects - the Sun is -26.7 and the Moon is -12.7
- Earth year = 365.24219 days
- Degree - at any time 180 degrees of sky is visible above
the horizon
- Arcsec is 1/3600 of a degree and 1/60 of an arcmin
- Planets represent objects whose diameters are given in
arcsecs
- Arcmin is 1/60 of a degree, typically used to measure the
diameter of a comet's coma and length of its tail
- The Sun and a Full Moon are very close to 1/2 degree in
diameter or 1,800 arcsecs across one's view of the sky
- The Andromeda Galaxy is about 2.5 degrees long
- Width of your fist held at arm's length is about 10
degrees
- Jupiter, at it's brightest, displays a diameter of nearly
0.8 arcmin
- The Ring Nebula (M57) has diameter of just over 1 arcmin
- Jupiter usually measures 45 to 50 arcsecs when closeest
to Earth, Uranus is 3 arcsecs, and Neptune is normally 2
arcsecs
- Imagine the palm of your hand as Pluto's orbit, the
nearest star is 4 miles away, the next star is 23 miles
away
- Jupiter is six times farther from the Sun than our Moon.,
but it is illuminated by only 1/36 as much sunlight
- Galaxies emit light in the blue
region because of the large amounts of dust
- Planetary nebulae emit light in the
green region
- Infrared objects are cool
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Copyright © 2010 Calvin Hill