# Presentation: 544543

## Finding our Origins with the Hubble and James Webb Space Telescopes

- Jonathan P. Gardner
- NASA’s Goddard Space Flight Center

## Sound Check

## Finding our Origins with the Hubble and James Webb Space Telescopes

- Jonathan P. Gardner
- NASA’s Goddard Space Flight Center

## Astronomical Search For Origins

- Big Bang

- First Galaxies

- Galaxies Evolve

- Stars

- Planets

- Life

## Beginnings are Important ...(Origins)

- ... So Are Changes(Evolution)

- David Jonathan Gardner, June 16, 1998

- David Jonathan Gardner, June 16, 2005

## A Brief History of Time

- Big Bang

- Particle Physics

- Now

- Atoms & Radiation

- First Galaxies

- Galaxies Evolve

- Planets, Life & Intelligence

- 300,000 years

- 3 minutes

- 1 billion years

- 13.7 billion years

- 400 million years

## Edwin P. Hubble(the man, not the telescope)

- Which is further away?How can you tell?

- Edwin P. Hubble, 1889-1953

- The “Spiral Nebulae” are “Island Universes”
- The Universe is Expanding
- Classification of Galaxies

## Distances

- If you know something’s intrinsic luminosity, and measure its apparent luminosity, you know how far away it is.

## Astronomer's Toolbox #1:Measuring Distances

- Cepheid Variable Stars: known period-luminosity relation.

- Suitable for nearby galaxies

- Supernovae: known maximum luminosity. Suitable for distant galaxies.

- Astronomers can measure distances if they know the intrinsic luminosity.

## Hubble Discovers the Universe

- Cepheids in the Andromeda galaxy showed it is 8 times further than the most distant star in our Galaxy.
-  Island Universes!

- “Planetary Nebula” are within our Galaxy.

- Hubble at Mount Wilson telescope

## The Doppler Shift - Sound

**OBJECT RECEDING: ****LOW-PITCHED WAVES**

**OBJECT APPROACHING: ****HIGH-PITCHED WAVES**

## Astronomer's Toolbox #2:Doppler Shift - Light

- Astronomer's Toolbox #2:Doppler Shift - Light

## Hubble’s Law

## Expansion of the Universe

- Early time

- Later

## Distance + Light travel time = Seeing the past.

- Astronomer's Toolbox #3:Looking Backwards in Time

- Distance

- Time

- Here & Now

- 1 Million light years away,
- 1 Million years ago

- 1 Billion light years away
- 1 Billion years ago

- Far, Far Away *means* Long, Long Ago

## Put the tools together

- To see backwards in time, to when the Universe was younger:
- We measure the Doppler Shift (Redshift)
- Hubble’s law tells us how far away it is
- The speed of light tells us how long ago the light was emitted.

- On average, more distant galaxies are fainter, so:
- To look backwards in time, you need a powerful telescope.

## The Hubble Sequence

- Hubble classified nearby (present-day) galaxies into Spirals and Ellipticals.

- The Hubble Space Telescope can extend this to the distant past.

## The Hubble Space Telescope has been pointed at one location in the sky for more than 500 hours, with more planned. 

- The Hubble Deep Fields

## Deepest View of the Universe

- Discoveries:
- History of star-formation in the Universe.
- Distant supernova confirms accelerating Universe.
- Distant galaxies are compact, “train wrecks”.

## History of Star Formation in the Universe

## Distant Supernova Confirms Accelerating Universe

- Pressure from “Dark Energy” accelerates the cosmic expansion, overcoming gravity

## Distant Galaxies are “Train Wrecks”

- Trace construction of Hubble sequence:

- How do “train wrecks” become spirals and ellipticals?

- By Merging!

## Galaxy Mergers

## The First Galaxies

- What did the first galaxies to form look like?
- They are very distant, and very faint.

## Infrared Light

- Light from the first galaxies is redshifted from the visible into the infrared.

- Infrared is heat radiation

- Most of the Sun’s energy is visible light

## How to win at Astronomy

- 108

- 1600

- 1700

- 1800

- 1900

- 2000

- Galileo

- Sensitivity Improvement over the Eye

- Year of observations

- Telescopes alone

- Photographic & electronic detection

- 106

- 104

- 102

- Huygens
-  eyepiece

- Slow f ratios

- Short’s 21.5”

- Herschell’s 48”

- Rosse’s 72”

- Photography

- Mount Wilson 100”

- Mount Palomar 200”

- Soviet 6-m

- Adapted from *Cosmic Discovery*, M. Harwit

- 1010

- CCDs

*HST*

- Big Telescopes with Sensitive Detectors in Space

- 1610

- 1665

- 1796

- 1926

## A Large Cold Telescope in Space

- James Webb Space Telescope

## HST vs. JWST - temperature

- Room Temperature

- -225° Celsius,-370° Fahrenheit

## HST vs. JWST - size

- 2.4 meter diameter

- 6.5 meter diameter

- How do you put a 6.5 meter mirror in a 4 meter rocket?

## HST vs. JWST - orbit

- 375 miles up

- Second Lagrange Point,1,000,000 miles away

- How will JWST get there?

- Ariane 5

## Astronomical Search For Origins

- Big Bang

- First Galaxies

- Galaxies Evolve

- Stars

- Planets

- Life

## Slide 32

## Finding our Origins with the Hubble and James Webb Space Telescopes

- Jonathan P. Gardner
- NASA’s Goddard Space Flight Center