Observing the Universe

Question 1

How has the location of observations changed over time?

Answer 1

originally observations were made from Earth

there are now telescopes in space to observe the Universe from above the Earth’s atmosphere

Question 2

How did the first scientists explore the Universe?

Answer 2

by observing the visible light emitted by stars

Question 3

Name four developments in technology and the impacts they had

Answer 3

-greater magnifications
we can observe galaxies that are far away

-recording observations using photography or digital cameras
we can gather more data

-can be made with greater precision
we get clearer images

-telescopes that can detect other parts of the electromagnetic spectrum
we can observe objects in space that emit more radio waves, infared, ultraviolet or x-rays than visible light

Question 4

What is the advantage of observing the universe from space instead of Earth?

Answer 4

some parts of the EM spectrum are absorbed by the Earth’s atmosphere

telescopes in space can observe these wavelengths before they reach the atmosphere

they can be put on satellites in spac

(e.g. ultraviolet telescopes need to be placed in orbit to detect ultraviolet radiation
radio waves can be detected by telescopes on Earth)

Question 5

Suggest why the cosmic microwave background radiation was detected on Earth [2]

Answer 5

the longer wavelength microwaves that form the cosmic microwave background radiation are not absorbed by the Earth’s atmosphere

Question 6

Explain why an X-ray telescope needs to be placed in orbit [2]

Answer 6

x-rays are absorbed by the Earth’s atmosphere so cannot be detected by Earth-based satellites

Question 7

Explain why visible light telescopes can be placed in Earth or in space [4]

Answer 7

Certain wavelengths of visible light can penetrate the Earth’s atmosphere so can be detected by Earth based telescopes

other wavelengths of visible light are absorbed by the atmosphere, so cannot be detected on Earth and this requires telescopes to be placed above the Earth’s atmosphere in space

Question 8

Explain how developments in modern telescopes have improved our knowledge of the Universe [4]

Answer 8

greater magnification - see further

record date digitally - gather more energy

greater precison - clearer images

detect other electromagnetic waves instead of light - can observe other objects that emit other types of EM waves