Unformatted text preview: and AUs.
The relative distances of the planets to the Sun are much easier to compare when expressed in AUs. For example,
you can say, the average distance from Venus to the Sun is about 0.7 AU, for Jupiter it is 5.2 AU, and for Pluto it is
40 AU. How far away are the stars? NASA The distance to the nearest star system to
our own Solar System is 40 trillion km!
12 Now let’s think about the distances to the stars. How far away are other stars?
Alpha Centauri is the closest star to our own solar system at a distance of 40 trillion km! It is not a single star,
but really a star system. Of the three stars in the system, the dimmest - called Proxima Centauri - is actually the
nearest star to the Earth. Thought Ques%on
On our 1 to 10 billion scale, if the Sun is on
the National Mall in Washington D.C., where
is Alpha Centauri?
E B A Sun Answer E
Google Maps 13 Lets put the distance to the nearest star on our 1-to-10 billion scale.
A. Baltimore, MD
B. Pittsburgh, PA
C. Chicago, IL
D. Denver, CO
E. San Francisco, CA
If we visualize the Sun as a cantelope, we’d have to go 4000 km to ﬁnd the next cantelope Light- years NASA Distance to Alpha Centauri =
4.2 light years
1 light-year = the distance light travels in 1 year = 10 trillion km 14 Even the nearest stars are so distant that astronomers don’t use AUs to talk about interstellar distances, we use
Light travels at a very fast speed (300,000 km/s), but interstellar distances are so vast that it takes years for
starlight to travel such distances!
1 light-year = the distance light travels in 1 year = ~10 trillion km, 6 trillion miles, or 63,000 AU! The nearest stars Richard Powell This map shows the star systems that lie within 12.5
light years of our solar system
15 This map shows the star systems that lie within 12.5 light years of our solar system. There are 23 star systems,
containing 33 stars, shown on the map. Some of the systems are multiple star systems...
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This note was uploaded on 10/23/2013 for the course ASTR 100 taught by Professor Dunne during the Fall '12 term at University of Illinois, Urbana Champaign.
- Fall '12