Understanding Astronomy

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The fact that GRBs come from every direction imply that GRBs don’t come from our galaxy, but from other galaxies spread in every direction!

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Radio wavelength observations are possible from Earth’s surface

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The Very Large Array (VLA) in New Mexico

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Different types of EM radiation require different types of telescopes

A refracting telescope uses a lens to concentrate incoming light

A reflecting telescope uses mirrors to concentrate incoming starlight

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Analyzing Spectra: The Properties of Light

Visible Light is one part of the electromagnetic (EM) spectrum.

EM radiation is described as a wave with wavelengths in the range 1x10-15 m to 100 m.

Visible light is only a tiny small part of the entire electromagnetic spectrum.

Little bits of light are called photons.

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Dividing Light Into a Spectrum

Astronomers separate out light into its individual components using a diffraction grating or using a prism - then they analyze each part independently!

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81

blue 4600 A 81

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blue 4600 A 81

green 5300 A 85

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blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

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blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

orange 6100 A 78

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blue 4600 A 81

green 5300 A 85

yellow 5800 A 83

orange 6100 A 78

red 6600 A 70

The spectrum is continuous.

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Spectra

Most light sources contain energy in lots of different wavelengths.

We can measure the brightness in various wavelength bands--the result is called the spectrum.

The spectrum (total character of light emitted) can tell us a lot about a source.

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A refracting telescope uses a lens to concentrate incoming light