![]() ![]() The two dimensions that specify this triangle are the parallax angle (defined as 1 arcsecond) and the opposite side (defined as 1 Astronomical Unit (AU), the distance from the Earth to the Sun).įigure 2. The parsec is defined to be the distance at which a star would have a parallax angle p equal to one second of arc (1/3600 deg). ![]() The other commonly used unit in astronomy and in Star Trek is called the Parsec (parallax of one arc second). The edge of the observable universe is 46.5 Giga light years away. The andromeda galaxy is 2.3 million light-years away. The Milky Way Galaxy is about 150,000 light-years across The distance from the Earth to the nearest star (Alpha Centauri A or B) after our Sun is 4.3 ly. With our new measuring sticks to hand we can give a few examples of the scale of the universe. ![]() All electromagnetic waves travel at a speed of x 299,792,458 ms -1 in a vacuum and with an average year being 365.25 days, one light year is 299,792,458 x 10 8ms -1 x (365.25 x 24 x 60 x 60) s =ĩ.46073 x 10 15 m. The light-year, as its name would suggest, is the distance travelled by light in one year. Moving to larger distances even the AU becomes unweildly and so the next suitable unit is the light-year. 1 Astronomical Unit = 149 598 000 km Light Year One natural and practical unit we can devise is the distance from the Sun to the Earth. We must introduce new length scales with which can span the heavens. The distances involved in the universe are so vast that metres or kilometers will just not suffice. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space. You just won't believe how vastly, hugely, mind-bogglingly big it is. In the words of Douglas Adams, the author of The Hitch-Hiker's Guide to the Galaxy: Space is big. ![]()
0 Comments
Leave a Reply. |