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Assembling the Jigsaw-PuzzlePicture of the Universe

Presented to

the NASA Night Sky Network

January 31, 2006

Dr. Jeffrey D. Rosendhal

Carl Sagan Center for

Earth and Space Science Education

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Assembling a Picture of the Universe: Some Basic Questions

• Do we actually have all the pieces?• Can we use all the colors?• Can we use the smallest pieces?

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The Electromagnetic Spectrum

Our eyes see only part of the electromagnetic spectrum…

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Some Fundamental Characteristics of Telescopes

• Sensitivity - Set primarily by the number of photons that can be collected in a given amount of time/Determines the fraction of all of the possible pieces that can be used

– Aperture– Image Quality– Background– Observation Time

• Angular Resolution - How close together can two objects be and still be seen as two objects/Determines the size of the pieces in the puzzle that can be used

– Aperture– Wavelength

• Wavelength/The different color pieces in the puzzle– Much of the spectrum is blocked by the atmosphere– Different physical information is carried by different types of light– Different techniques have to be used to collect and use photons of different

energies

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The World’s Most Famous Mirror

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High energy x-rays must skip off the shiny mirror surface at shallow angles

to be observed, much different than how optical light telescopes work.

Collecting x-rays is like skipping stones on a pond!

Just Skimming the Surface…

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Because gamma rays cannot be focused, Swift uses a unique technique that pinpoints the location of a gamma-ray burst by the shadow cast on

an array of detectors.

Shadow Play…

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“Invisible” Light in Astronomy

Each part of the spectrum provides a piece of the puzzle in understanding our universe.

Star birth & star death

Warm dustStars & dust

Young stars

Black holes & neutron stars

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Ultraviolet Images of a Galaxy Clearly Show the Young, Hot Stars

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The Sombrero Galaxy as Seen by Hubble and Spitzer

Different wavelengths reveal different components of the galaxy

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Infrared measurements in Andromeda clearly reveal the hot dust

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The Crab Nebula: The Aftermath of a Supernova

The Crab Nebula is all that remains of a once-bright star. The white box on the left shows the area covered by the image on the right.

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A visible light image of Centaurus A, an interesting galaxy observed with a wide lane of dust across its center.

Visible Light View of an Interesting Galaxy

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X-rays Reveal the Real Action!

A high-energy jet blasts outward from the galaxy’s center, evidence for a powerful black hole with the mass of one billion Suns!

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The ability to detect faint features reveals new phenomena

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Seeing Faint Objects is Crucial…As is Taking a Time Sequence of Images

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Spatially resolved spectroscopy reveals the presence of a Black Hole

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X-ray observations of the center of our own galaxy clearly reveal the hot gas swirling into a massive black hole

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Sometimes, just thinking about the meaning of what you are looking at can be very powerful

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The Tools of Our Search

We collect light from distant objects…

To study fundamental questions in astronomy

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Some current key astronomical problems are really very familiar to everyone

• How high is up?• How far can we see?• Have we discovered everything there is to discover?• Twinkle, twinkle little star how I wonder what you are….?• How did we get here?• Where are we going?• Are there other worlds?• Is anybody else out there?

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The infrared reveals the clouds of gas and dust associated with starbirth

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Detailed study of gas clouds enable astronomers to understand the conditions that regulate the formation of stars within a cloud

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Infrared observations allow us to see the stars forming within the clouds and the warm dust itself

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Infrared capabilities enable astronomers to see through the dust in a cloud and observe the embedded cluster of young stars

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Early observations of the disk around the star Beta Pictoris

The kink within the disk is probably due to the presence of one or more embedded objects within the disk

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We now know that young stellar disks are common

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Infrared Observations of the Fomalhaut Circumstellar Disk

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Observational capabilities have reached the point where we are now able to see structure within a disk

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An Active Young Star With a Jet

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The infrared also reveals outflows in young stars

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Detection of ices in a protoplanetary disk

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Stars with planets have retained their dust disks

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Some stars “peacefully” eject shells of material towards the end of their lives

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Planetary Nebulae: Remnants of Old, Dying Stars

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Different wavelengths reveal different aspects of the physics of a supernova remnant

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Optical and x-ray images of the remnant of SN 1987a in the Large Magellanic Cloud

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What Happens Next?

• Continued access to the entire electromagnetic spectrum

• Improved sensitivity– Use of segmented mirrors and arrays– Spectroscopy of faint objects

• Continued increases in angular resolution at all wavelengths– Interferometers

• Use of new tools for exploring the Universe– Gravity Waves

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The further into space we observe, the further back in time we see. Observers become time travelers through the universe.

Cosmic Time Machines…

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Infrared measurements reveal distant galaxies in the Hubble Ultra Deep Field

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The James Webb Space Telescope will continue Hubble’s legacy with more light collecting capability in a less massive package, resolving the

mysteries of our universe from above the confines of Earth!

New telescopes will look back to the era when galaxies first formed

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The Chandra X-Ray Observatory and the future, more capable Constellation-X mission, with four identical X-ray telescopes working as one, will continue to explore the limits of space and time in the hot, turbulent universe.

The Whole Picture…

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High Resolution Imaging

Over small fields ofview SIM will show details that currently elude large telescopes.A simulated globular cluster core is used to illustrate this.

Cluster Core Model

SIM

HST-WFPC2

Resolution (FWHM) 53 milliarcsec

Resolution (FWHM)10 milliarcsec

Field of View 0.3 arcsec

“true star positions”

actual field of viewlarger than shown

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Telescopes that block the light from the central star can take images of planets that might be in orbit around them.

The Keck Interferometer combines the light of two 10-meter telescopes to take images of hot Jupiter-size planets that shine bright in infrared light.

Keck Interferometer

The Terrestrial Planet Finder Coronagraph (left) and Interferometer

The two Terrestrial Planet Finder observatories will search from space for planets as small as Earth and for signs about whether they can support life.

Blocking out the bright light from the central stars will allow astronomers to search for earth-like planets

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How will we know whether a planet supports life?

Look for evidence of oxygen

Look for liquid water

Analyze the reflected light from the planet to see if the planet has an atmosphere

Look for signs of biological activity (methane)

and rule out other explanations.

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LISA “dances about” as gravitational waves pass through the surrounding space.

Where Do Gravitational Waves Come From?

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Three individual craft each separated by 5 million kilometers will measure changes to tiny 4cm cubes to a precision of the width of an atom!

Measure Rippling Space-Time? Incredibly Possible!