What Does the Infrared Have to Do With Space?

Look at the difference between visible and infrared light!

What is Infrared Light?• Infrared light is a form of electromagnetic

radiation, one that is invisible to our eyes.• Infrared light is what we commonly think of as

“heat” radiation. Heat is the kinetic energy stored in the motion of atoms and molecules.

• Infrared light is emitted by anything in the universe with a temperature (above absolute zero).

• Objects below 1,000 degrees C radiate mostly in the infrared.

Infrared and Temperature

Dr. Michelle Thaller (Senior Scientist, California Institute of Technology) seen with an infrared camera (after playing with an ice cube). Things can look quite different in infrared light.

Properties of Infrared Light

• Infrared light can pass through many things that block visible light, like smoke and dust (and most plastics).

Michelle Inside of Black Plastic Bag

Fireman Inside of Smoke-filled Room

Properties of Infrared Light

• Infrared Light is also blocked by things that let visible light through (like our atmosphere!)

A Piece of Glass Completely Blocks Infrared Light

• Because of its relatively long wavelength, Infrared Light can travel more readily through Interstellar Dust (similar in size to smoke) than visible light.

What a difference Temperature Makes (Blackbody Radiation)

Infrared Astronomy Explores:• Objects in space that are too cool to radiate visible light

– Planets, interstellar dust clouds, Brown Dwarfs, proto-planetary disks

• Objects and processes that are obscured by dust– Star and planet formation, active galactic nuclei (black

holes)• The Very Distant Universe

– Radiation from the early universe has been red-shifted into the infrared

– Young galaxies appear to be shrouded in dust• Interesting Chemistry

– Spectral lines of water, CO2, organic molecules in infrared region

The Heritage of Infrared Astronomy

• Infrared discovered in 1800 by William Herschel• First infrared telescopes built in 1960’s.• Kuiper Airborne Observatory in 1970’s.• IRAS (Infrared Astronomical Satellite) in 1983.• ISO (Infrared Space Observatory) flown by ESA

in 1995.• SIRTF (Space Infrared Telescope Facility)

launched in 2003.

BROWN DWARFSBROWN DWARFS

Failed Stars of the Universe

The mass of a brown dwarf is no more than eight percent of the Sun’s mass, and many are not much bigger than Jupiter.

Infrared Spectra of a Red Dwarf and a Brown Dwarf

The major difference in the two is the high level of methane found only in brown dwarfs.

Extrasolar Planet and Planetary Disk Detection

Near Infrared image of Beta Pictoris

This is an example of a warm disk of material around a star where planets may be born.

These warm dust disks around stars give clues to the presence of planets

Orion Nebula

Young stars, mostly unseen, are hidden in these clouds.

Visible Light

Orion Nebula

What a difference the infrared view makes!

Infrared view

Active Galactic Nuclei (Giant Black Holes)

What powers the most luminous galaxies in the universe? Perhaps giant black holes fed by turbulent galaxy mergers. Whatever it is lies hidden behind dust.

And Closer to Home…

The Center of the Milky Way in visible (left) and infrared (right) shows signs of having a similar massive black hole.

Seeing to the end of the Universe

The farthest objects in the universe are heavily red-shifted, in some cases completely out of the visible range. Infrared can probe deeper, exploring the first proto-galaxies as much as 14 billion light years away.

Space Infrared Telescope Facility

SIRTF launched on Sunday, August 24, 2003 at 11:35:39

p.m. MDT

Which waves of light cannot be observed from Earth?