Absorption lines of a galaxy shift toward the blue end of the spectrum when it moves toward Earth. The lines shift to the red end of the spectrum when a galaxy moves away from Earth.

Hubble’s Law How do astronomers know that the universe is expanding?

Hubble’s Law red shift—

Hubble’s Law Hubble’s Law is -

The Big Bang Theory What is the big bang theory, and what evidence supports it?

The Big Bang Theory The big bang theory states that –

The first stars and galaxies formed – The Big Bang Theory Big bang occurred 13.7 billion years ago. The universe began – The first stars and galaxies formed – The solar system, and Earth, formed about – First stars and galaxies formed 200 million years after big bang. Solar system formed 4.6 billion years ago. Earth today

Continued Expansion How can dark matter be detected?

Continued Expansion Dark matter is –

According to Hubble’s Law, Assessment Questions According to Hubble’s Law, the apparent wavelength of light is dependent on relative motion compared to the observer. the amount of matter in a large region of the universe is constant over long periods of time. the age of a star is proportional to the red shift of its spectrum. galaxies are moving away from Earth at speeds proportional to their distance from Earth.

How is dark matter in the universe detected? Assessment Questions How is dark matter in the universe detected? direct observation its effect on electromagnetic interactions its gravitational effects on matter very faint background radiation in the universe

Assessment Questions Based on the size of the universe and its rate of expansion, the big bang is calculated to have occurred between 13 and 14 billion years ago. True False