6.5 Observations outside of Earth's Atmosphere

Space telescope

A telescope located above Earth's atmosphere to avoid atmospheric absorption and turbulence.

Atmospheric distortion

Blurring and distortion of astronomical images caused by Earth's atmosphere.

Atmospheric turbulence

Movement in Earth's atmosphere that limits the resolution of ground-based telescopes.

Advantages of space telescopes

They avoid atmospheric turbulence and can observe wavelengths blocked by Earth's atmosphere.

Disadvantages of space telescopes

They are expensive and difficult or impossible to repair.

Infrared astronomy

The study of astronomical objects using infrared radiation.

Water vapor absorption

The strong absorption of infrared radiation by water vapor in Earth's atmosphere.

Airborne telescope

A telescope carried above much of Earth's atmosphere by an aircraft.

Learjet telescope

An early airborne telescope used for infrared observations in the 1960s.

Kuiper Airborne Observatory

An airborne observatory that operated from 1974–1995.

SOFIA

A 2.5-meter infrared telescope mounted on a Boeing 747 that operated from 2010–2022.

IRAS

The first all-sky infrared survey telescope, launched in 1983.

Spitzer Space Telescope

An infrared space telescope that operated from 2003–2020.

James Webb Space Telescope (JWST)

A 6.5-meter segmented space telescope optimized for infrared observations and launched in 2021.

JWST primary mirror

A 6.5-meter segmented mirror designed for infrared astronomy.

JWST sunshield

A large shield that protects the telescope from sunlight and helps keep it extremely cold.

JWST location

JWST orbits about 1.5 million kilometers from Earth, far beyond the Moon.

JWST science goals

Studying the earliest galaxies, star-forming regions, and exoplanet atmospheres.

Hubble Space Telescope (HST)

A 2.4-meter space telescope launched in 1990 that observes visible, ultraviolet, and infrared light.

Hubble mirror problem

An error in the shape of Hubble's original mirror that was corrected with corrective optics in 1993.

Hubble Ultra-Deep Field

A Hubble image showing approximately 10,000 galaxies.

High-energy observatory

A space observatory designed to detect ultraviolet, X-ray, or gamma-ray radiation.

Ultraviolet astronomy

Astronomy using ultraviolet radiation, which generally requires observations above Earth's atmosphere.

X-ray astronomy

Astronomy using X-rays, which generally requires space-based observatories.

Gamma-ray astronomy

Astronomy using gamma rays, which generally requires space-based observations.

Chandra X-ray Observatory

A space observatory launched in 1999 that produces high-resolution X-ray images.

XMM-Newton

An X-ray space observatory launched in 1999 that performs X-ray spectroscopy.

Fermi Gamma-ray Space Telescope

A space observatory launched in 2008 for studying high-energy gamma rays.

X-ray optics

Special telescope optics needed because X-rays normally pass through ordinary materials.

Gamma-ray detection

Some ground-based arrays detect atmospheric particle cascades produced by incoming gamma rays.

Gaia

A space observatory launched in 2013 that uses visible light to precisely map the Milky Way.