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

02.21.07

Hot, Dry, and Cloudy (Artist Concept)

This artist's concept animation shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two "hot Jupiter" worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the "fingerprints" of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged, even as the planet disappeared from view.

To capture spectra of the planets, Spitzer observed their secondary eclipses with its spectrograph. It took a spectrum of a star together with its planet, then, as the planet disappeared from view, a spectrum of just the star. By subtracting the spectrum of the star from the spectrum of the star and planet together, astronomers were able to determine the spectrum of the planet itself.

Neither of the parent stars for HD 209458b or HD 189733b can be seen with the naked eye. HD 209458b is located about 153 light-years away in the constellation Pegasus, while HD 189733b is about 62 light-years away in the constellation Vulpecula. Both planets zip around their stars in very tight orbits; HD 209458b circles once every 3.5 days, while HD 189733b orbits once every 2.2 days.

Of the approximately 200 known exoplanets, there are 12 besides HD 209458b and HD 189733b whose orbits are inclined in such a way that, from our point of view, they pass in front of their stars. At least three of these transiting exoplanets are bright enough to follow in the footsteps of HD 209458b and HD 189733 and reveal their infrared spectra to Spitzer. Astronomers hope to use Spitzer's spectrograph in the future to study HD 209458b and HD 189733b again in much greater detail, and to examine some of the other candidates for the first time.

Browse Videos in Science Animations

2040100 per page

Details or Icons

Page-nav-left Page 2 of 4 Page-nav-right

Go to page

04.18.07

Infrared Rose

This movie begins by showing an optical image of the Rosette nebula, a turbulent star-forming region located 5,000 li...

Watch now

03.29.07

Two Suns Raise Family of Planetary Bodies

This artist's animation depicts a faraway solar system like our own -- except for one big difference. Planets and ast...

Watch now

Now Playing

02.21.07

Hot, Dry, and Cloudy (Artist Concept)

This artist's concept animation shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA...

Watch now

12.18.06

Stars Spring Up Out of the Darkness

This artist's animation illustrates the universe's early years, from its explosive formation to its dark ages to its ...

Watch now

11.07.06

Hubble-Spitzer Orion

This video cycles between the Hubble view, the Spitzer view, and the combined Hubble-Spitzer view of the Orion Nebula.

Watch now

11.07.06

Making a Great Observatories Composite

This video shows how a Hubble image and a Spitzer image of the Orion Nebula were combined to create a new, multi-wave...

Watch now

10.30.06

Who Ya Gonna Call?

NASA's Spitzer Space Telescope is a galactic ghost buster, spotting hidden massive stars and other monsters lurking i...

Watch now

10.26.06

Order Amidst Chaos of Star's Explosion

This artist's animation shows the explosion of a massive star, the remains of which are named Cassiopeia A. NASA's Sp...

Watch now

10.12.06

Fire and Ice Planet (without data plot)

This artist's animation shows a blistering world revolving around its nearby "sun." NASA's infrared Spitzer Space Tel...

Watch now

10.12.06

Fire and Ice Planet

This artist's animation shows a blistering world revolving around its nearby "sun." NASA's infrared Spitzer Space Tel...

Watch now

08.14.06

Journey to Orion

This movie begins with a visible view of the famous Orion constellation. Superimposed on the area near Orion's sword ...

Watch now

07.24.06

Stars Can't Spin Out of Control

This artist's animation demonstrates how a dusty planet-forming disk can slow down a whirling young star, essentially...

Watch now

06.05.06

Fade to Red

This animation shows the Andromeda galaxy, first as seen in visible light by the National Optical Astronomy Observato...

Watch now

04.05.06

Birth of 'Phoenix' Planets?

This artist's animation depicts the explosive death of a massive star, followed by the creation of a disk made up of ...

Watch now

03.16.06

Cigar Galaxy up in Smoke

This movie compares a visible-light view of the "Cigar galaxy" to an infrared view from NASA's Spitzer Space Telescop...

Watch now

06.09.05

The Cry of Cassiopeia A

This animation begins with a stunning false-color picture of the supernova remnant Cassiopeia A. It is made up of ima...

Watch now

06.02.05

Space Eyes See Comet Tempel 1

This artist's concept of Tempel 1 illustrates the comet's shape, reflectivity, rotation rate and surface temperature,...

Watch now

05.30.05

Carina in Context

This animation starts with an image of a larger but lower resolution image of the Carina Nebula from the Midcourse Sp...

Watch now

05.30.05

Pillars Behind the Dust

The movie begins with a visible-light picture of the southern region of our Milky Way galaxy then slowly zooms into t...

Watch now

05.04.05

A More Spectacular Sombrero

This movie shifts from the well-known visible-light picture of Messier 104 taken by the Hubble Space Telescope to inf...

Watch now