The Spitzer Space Telescope website will be down on Tuesday July 29th from 9am PDT to 10am PDT for server maintenance. Thank you for your patience.

Download Video

Video Information

Subscribe to Series

05.09.07

Blacker than Black

This artist's animation illustrates the hottest planet yet observed in the universe. The scorching ball of gas, a "hot Jupiter" called HD 149026b, is a sweltering 3,700 degrees Fahrenheit (2,040 degrees Celsius) -- about three times hotter than the rocky surface of Venus, the hottest planet in our solar system. The planet is so hot that astronomers believe it is absorbing almost all of the heat from its star, and reflecting very little to no light. Objects that reflect no sunlight are black. Consequently, HD 149026b might be the blackest known planet in the universe, in addition to the hottest.

The temperature of this dark and balmy planet was taken with NASA's Spitzer Space Telescope. While the planet reflects no visible light, its heat causes it to radiate a little visible and a lot of infrared light. Spitzer, an infrared observatory, was able to measure this infrared light through a technique called secondary eclipse. HD 149026b is what is known as a transiting planet, which means that it crosses in front of and passes behind its star -- the secondary eclipse -- when viewed from Earth. By determining the drop in total infrared light that occurs when the planet disappears, astronomers can figure out how much infrared light is coming from the planet alone.

The Spitzer observations of HD 149026b also suggest a hot spot in the middle of the side of the planet that always faces its star. Even though the planet is black, the spot would glow like a black lump of charcoal. HD 149026b is thought to be tidally locked, just as our moon is to Earth, such that one side of the planet is perpetually baked under the heat of its sun.

Astronomers think that HD 149026b is probably blazing hot on its sunlit side, and much cooler on its dark side. A similar phenomenon was observed previously by Spitzer for the planet Upsilon Andromedae b. In the case of both planets, heat is not being evenly distributed across their surfaces. This is the opposite of what happens on Jupiter, where temperature differences are minimal all around.

HD 149026b is located 256 light-years away in the constellation Hercules. It is the smallest known transiting planet, with a size similar to Saturn's and a suspected dense core 70 to 90 times the mass of Earth. It speeds around its star every 2.9 days.

Browse Videos in Science Animations

2040100 per page

Details or Icons

Page-nav-left-disabled Page 1 of 2 Page-nav-right

Go to page

ssc2014-02v1

03.20.14

Panning Through the Milky Way

ssc2012-11v1

07.18.12

Flying Out to GJ 436 and its Planets

ssc2010-08v1

10.19.10

Weird Warm Spot on Exoplanet

ssc2010-06v1

07.22.10

Mini Soccer Balls in Space

ssc2010-06v2

07.22.10

Buckyballs Jiggle Like Jello

ssc2009-19v1

10.06.09

Saturn Family Tour

ssc2009-16v1

08.10.09

Planetary Demolition Derby

ssc2008-09v2

05.05.08

Dissecting a Light Echo

ssc2008-09v1

05.05.08

Cauldron of Light

ssc2007-19v1

11.29.07

Pulling Back the Curtain of Dust

ssc2007-09v1

05.09.07

Blacker than Black

ssc2007-09v2

05.09.07

Mapping Exotic Worlds

ssc2007-09v3

05.09.07

How to Map a Very Faraway Planet

ssc2007-08v2

04.18.07

Highway to the Danger Zone

ssc2007-08v1

04.18.07

Infrared Rose

ssc2006-22v1

12.18.06

Stars Spring Up Out of the Darkness

ssc2006-21v2

11.07.06

Hubble-Spitzer Orion

ssc2006-20v1

10.30.06

Who Ya Gonna Call?

ssc2006-18v1

10.12.06

Fire and Ice Planet

ssc2006-16v1

08.14.06

Journey to Orion

ssc2006-15v1

07.24.06

Stars Can't Spin Out of Control

ssc2006-14v1

06.05.06

Fade to Red

ssc2006-10v1

04.05.06

Birth of 'Phoenix' Planets?

ssc2006-09v1

03.16.06

Cigar Galaxy up in Smoke

ssc2005-14v1

06.09.05

The Cry of Cassiopeia A

ssc2005-13v1

06.02.05

Space Eyes See Comet Tempel 1

ssc2005-12v2

05.30.05

Carina in Context

ssc2005-12v1

05.30.05

Pillars Behind the Dust

ssc2005-11v1

05.04.05

A More Spectacular Sombrero