DENTON (UNT), Texas -- On Sept. 23, 1846, 169 years ago, astronomers discovered Neptune using mathematics. Neptune is the eighth planet from the Sun.

Director of the UNT Astronomy program and NASA Ambassador Ron DiIulio is available for interviews to discuss Neptune's anniversary. DiIulio is available by email at Ronald.DiIulio@unt.edu or by phone at 940-369-8213.

Neptune facts:

• Neptune's atmosphere is made up of Hydrogen, Helium and Methane.
• Neptune takes nearly 165 Earth years to orbit the Sun.
• One day on Neptune – the amount of time it takes the planet to complete a rotation - is about 16 Earth hours.
• Neptune has 13 confirmed moons.