6 - Telescopes

Infrared Radiation lets us see through ______ ____.

Cosmic dust

The distant universe is also ___-_______ so we need IR to see more distant galaxies too.

Red-shifted

What radiation do forming stars give off?

Ultraviolet

__ radiation is strongly emitted by very short-lived massive stars

UV

Why is UV radiation only seen by space telescopes?

It is absorbed by the atmosphere

X-rays and Gamma Rays trace high energy sources: _________ _____ _____ and ___ ___. These are heavily absorbed by the atmosphere so only space telescopes can observe them.

Accreting black holes; hot gas

Accreting Black Holes are called ______ _______ ______ (AGN) or Quasers, depending on type.

Active Galactic Nuclei

What is the process of the first stars and galaxies heating the universe called?

Cosmic Dawn

What is the Big Bang afterglow?

Cosmic Microwave Background Radiation (CMB)

What is used to split light up by wavelength, such that you can measure each wavelength brightness separately?

Prism

What are two uses of Spectroscopy?

Can look for emission/absorption at very specific wavelengths; can learn about the movement of the light source

What are two challenges of Spectroscopy?

Light is split up so faint, so takes much longer to measure than photometry; can’t measure as many objects in same time, and can’t see faint things at all

Which process means receding objects look redder and advancing objects look bluer?

Doppler shift

Why do stars and smaller galaxies twinkle, putting a limit on how clearly we can see small objects?

Earth’s atmosphere

What are 2 benefits of space telescopes?

High resolution imaging; can measure distant galaxies and faint stars