# Astro-Physical Calculator

This is basically the calculator on Chris Dolan's webpage with a couple more buttons added for high-energy astrophysicists. See at the bottom of the page for more details.

This calculator only works if your browser can process JavaScript.

Units: CGS SI
 Physical Constants Astronomical Constants Planetary Data Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto

The Units switch above does not change the units of your calculation! It only specifies the units of the constants buttons for future entries!

NAME SYMBOL NUMBER CGS UNITS
Velocity of light c 2.998 x 1010 cm s-1
Planck constant h 6.626 x 10-27 erg s
Gravitational constant G 6.67 x 10-8 cm3 g-1 s-2
Electron charge e 4.803 x 10-10 esu
Mass of electron m_e 9.1096 x 10-28 g
Mass of proton m_p 1.6724 x 10-24 g
Mass of neutron m_n 1.6747 x 10-24 g
Mass of hydrogen m_H 1.6733 x 10-24 g
Atomic mass unit amu 1.661 x 10-24 g
Avagadro's number N_A 6.0222 x 1023
Boltzmann constant k 1.38 x 10-16 erg K-1
Electron volt ev 1.602 x 10-12 erg
Rad'n density constant a 7.5646 x 10-15 erg cm-3 K-4
Stefan-Boltzmann const sigma 5.67 x 10-5 erg cm-2 K-4 s-1
Thomson cross section sigma_T 6.6524 x 10-25 cm2
Electron rest mass energy E_e 8.18710414 x 10-7 erg
Fine structure constant \alpha 7.29735308 x 10-3
Rydberg constant R 2.17992 x 10-11 erg
Year yr 3.156 x 107 s
Astronomical unit AU 1.496 x 1013 cm
Parsec pc 3.086 x 1018 cm
Light year ly 9.463 x 1017 cm
Solar mass M_sun 1.99 x 1033 g
Solar radius R_sun 6.96 x 1010 cm
Solar Luminosity L_sun 3.9 x 1033 erg s-1
Solar Temperature T_sun 5780 K
In the calculator above, the Period has been converted to seconds and the Semi-Major Axis has been changed to cm.

Name Mass (g) Radius (cm) Period (yr) Semi-Major (AU) Eccentricity
Mercury 3.303 x 1026 2.439 x 108 2.4085 x 10-1 3.87096 x 10-1 0.205622
Venus 4.87 x 1027 6.05 x 108 6.1521 x 10-1 7.23342 x 10-1 0.006783
Earth 5.976 x 1027 6.378 x 108 1.00004 x 100 9.99987 x 10-1 0.016684
Mars 6.418 x 1026 3.397 x 108 1.88089 x 100 1.523705 x 100 0.093404
Jupiter 1.899 x 1030 7.14 x 109 1.18622 x 101 5.204529 x 100 0.047826
Saturn 5.686 x 1029 6 x 109 2.94577 x 101 9.575133 x 100 0.052754
Uranus 8.66 x 1028 2.615 x 109 8.40139 x 101 1.930375 x 101 0.050363
Neptune 1.03 x 1029 2.43 x 109 1.64793 x 102 3.020652 x 101 0.004014
Pluto 1 x 1025 1.2 x 108 2.47686 x 102 3.991136 x 101 0.256695

Note: This calculator was written and tested on a Unix computer. If it looks bad to you, try making your window wider. The calculator looks especially bad on Macs, unfortunately...

Most of the JavaScript code for this calculator came (with permission) from the Scientific Calculator by Rolf Howarth. (rolf@insect.demon.co.uk)

The code for the comment field at the top of the page came from Bruce Busby (bbusby@umich.edu)

2008-Nov-26 : Initial code from http://www.astro.wisc.edu/~dolan/constants/calc.html (DM)
2008-Nov-26 : Added Thomson cross section and electron rest mass energy (DM)

Constants Page

This is almost a "mirror" of the Conversions page by Ulrich Hopp (http://www.usm.uni-muenchen.de/people/hopp/conversion.html), mirrored (after changing the colour scheme) on 2010 June 15.

This page is maintained by Dipankar Maitra.   Last updated: January 13, 2010