A105 Stars and Galaxies

Homework #4 due today Telescopes

Read unit 30 for next week News Quiz Tuesday First Exam on Sept. 28

Today’s APOD

Announcements!• News Quiz on Tuesday on the new

Atacama Radio Telescope

• First Exam on Thursday, Sept. 28– Review Sheet as Oncourse Announcement

• Oncourse Update - oncourse.iu.edu

Special Guest!!!

• Professor Liese van Zee

Three types of spectra

Continuous – Thermal RadiatorEmission – from hot gasAbsorption – continuous spectrum passes through cooler gas

Electromagnetic Spectrum

Space Telescopes

• NASA’s four Great Observatories

– Visible – Hubble Space Telescope– Gamma rays - Compton Gamma Ray Obs.– X-rays - Chandra X-ray Observatory– Infrared - Spitzer Space Telescope

Hubble Trivia

• Launched April 24, 1990, by Space Shuttle Discovery

• Visible light, ultraviolet, and near-infrared

• Orbits about 380 miles (611 km) above Earth

• About the size of a bus• Primary mirror ~ 2 meters• Named after astronomer Edwin

Hubble– discovered galaxies beyond our

Milky Way– determined that space is

expanding

Keeping track of Hubble

• Where is Hubble now?

• When can I see Hubble?

Where is the Hubble Space Telescope?

www.heavens-above.com

Space and Ground in Partnership

• Supernova brightness measured with Hubble

• Red shifts measured from the ground

The Chandra X-Ray Telescope

How Do X-Ray Telescopes Work?• X-rays do not reflect off mirrors the same way that visible light does• X-ray photons penetrate into the mirror in much the same way that

bullets slam into a wall• X-rays ricochet off mirrors like bullets off a wall• X-ray telescopes are very different from optical telescopes.

X-ray mirrors are precisely shaped and aligned to incoming x-rays. They look more like barrels than the familiar dish mirrors of optical telescopes.

The Spitzer

InfraredSpace

Telescope

Spitzer Trivia

• Launched 25 August 2003• Estimated Lifetime:2.5 – 5 years • Orbits the Sun, Earth-trailing, heliocentric• Telescope – only 85 cm diameter (33.5”)

www.spitzer.caltech.edu/about/now.shtml

Compton Gamma Ray Observatory

• 1991 – 2000• solar flares

• gamma-ray bursts• pulsars

• nova• supernova explosions

• black holes• quasar emission

What does it cost?????• Proposed NASA budget for 2007: $16.8B

– Science $5.3 billion *– Exploration $4.0 billion– Aeronautics $0.7 billion– Space Ops $6.2 billion– Education $0.15 billion

*All astronomy research and space telescopes are in this part.

Comparable Spending• $20 billion at jewelry stores (US)• $24 billion at liquor stores (US)• $40 billion on weight loss (US)• $23.5 billion on candy and gum (US)• $31 billion on pet toys and supplies (US)• $7 billion on video rentals (US)• $18 billion on makeup (worldwide)• $35 billion on bottled water (worldwide)

Great Observatories’ Costs

• Hubble Space Telescope: $6 billion

• Chandra X-ray Telescope: $2.5 billion

• Spitzer IR Telescope: $1.2 billion

• Compton Gamma Ray Tel: $0.56 billion

Question: Why does society chose to support science research at this cost?

The Hubble Space Telescope

Homework Review• Today’s homework…

• Next week’s:– www.astro.indiana.edu/novasearch

• Check back with Hubble:• Where is the Hubble Space Telescope?

Read unit 30 News Quiz on Tuesday NovaSearch homework

(#5) worksheet due Thursday

EXAM ALSO THURSDAY