Expert: Tom Whiting - 5/14/2010

Question
hi um i was just wondering if you could answer a few questions. i would really appreciate it.
whats the distance from earth to the following planets in AU;
mars, jupiter, saturn, uranus, neptune, and pluto.
thanks

Answer
Hi Roxy,
As you probably know, the Earth-Sun distance of 93 million miles is 1 AU.
So all you have to do is memorize the various planets' distances from the SUN in AU and then subtract 1...  assuming you are taking the Earth on the same side of the sun as the planet in question.
(BUT if you're assuming the Earth is on the far side of the sun from said planet, then you have to add 1 AU.)
SO, just memorize Mars to Pluto, 1.52, 5.2, 9.5, 19.2, 30.1, and Pluto is 39.4... in AU's... and then do your adding or subtracting of 1 as mentioned above.
There is a website that gives that to you too, distance from the sun,  at
http://windows2universe.org/our_solar_system/planets_table.html

An easier way to do the planets from the sun in AU is to remember a little ditty called Bode's law, which wasn't discovered by Bode, nor is it a law (because it doesn't hold for Neptune and Pluto).  But it closely works for Mercury to Uranus.
Take the series of three, and double it, like this:
0, 3, 6, 12, 24, 48, 96, 192, 384....
Now add 4 to each getting
4, 7, 10, 16, 28, 52, 100, 196, 388... and now divide by 10 (just move decimal point to the left one notch)...
and you get...
.4, .7, 1.0, 1.6, 2.8, 5.2, 10.0, 19.6  etc etc.  PRESTO  - distances from the sun of all the planets in AU, except Neptune because it breaks down on the outer planets.  (Notice the extra number of 2.8 AU is the average asteroid belt distance between Mars and Jupiter).
Hope this helps,
Clear Skies,
Tom Whiting
Erie, PA USA

FOLLOW Up:
Opps... that should have been 0.4, 0.7, 1.0, etc etc... missed a decimal point there.
tom