Exploring Space

Question 1

What is the Universe made up of and held together by?

Answer 1

The Universe is made up of billions of galaxies which are collections of stars help together by the force of gravity.

Question 2

What are distances in the Solar System measured in?

Answer 2

Distances in the Solar System are measured in Astronomical Units (AU). One AU is the average distance from the Earth to the Sun.

Question 3

Which planet is closest to the Sun?

Answer 3

Mercury.

Question 4

Which planet is furthest away from the Sun?

Answer 4

Neptune.

Question 5

How far across is the Universe believed to be?

Answer 5

The Universe is believed to be 10 to the power of 27m across.

Question 6

What are very large distances in space measured in?

Answer 6

Very large distances in space are measured in light-years. A light-year is the distance travelled by light (through a vacuum) in a year.

Question 7

How big is the Universe in light years?

Answer 7

The size of the Universe is about 100 billion light years.

Question 8

What do larger magnification telescopes allow astronomers to do?

Answer 8

Larger magnification telescopes allow astronomers to view starts and galaxies deep into space.

Question 9

What do space probes do?

Answer 9

Space probes are sent out on flyby missions to detect the presence of water and minerals on other planets. They send out data and photographs back to Earth using radio waves.

Question 10

What do robotic landers do?

Answer 10

Robotic landers can be sent out to planets. They collect soil samples and search for microscopic life forms, such as bacteria.

Question 11

What does SETI stand for?

Answer 11

SETI stands for the Search for Extraterrestrial Intelligence.

Question 12

What is SETI doing?

Answer 12

SETI is looking for radio broadcasts from alien civilisations, which may exist on other planets orbiting distant stars.

Question 13

What do the photographs taken using parts of the EM spectrum other than visible light reveal?

Answer 13

Photographs taken using parts of the EM spectrum other than visible light, such as X-rays, reveal different information about the structure of space bodies, such as their magnetic fields.

Question 14

What is a spectrometer?

Answer 14

A spectrometer is a device used for looking at the spectrum of light.

Question 15

What do hot and cold stars emit?

Answer 15

Hot stars emit more blue light and cool starts emit more red light.

Question 16

How can scientists identify the chemical composition of stars?

Answer 16

Scientists can identify the chemical composition of stars by examining the light they emit with a spectrometer.

Question 17

Why can we use radio waves for communication?

Answer 17

Radio waves are not absorbed at all by the atmosphere so they can be used for communications.

Question 18

Are gamma and X-rays absorbed by the atmosphere?

Answer 18

Yes.

Question 19

What is the Doppler effect?

Answer 19

The Doppler effect is where sound waves are being squashed together as the car comes towards you and stretched as the car moves away.

Question 20

What is the blue-shift?

Answer 20

The wavelength of light decreases (and frequency increases) as a light source moves towards an observer.

Question 21

What is the red-shift?

Answer 21

The wavelength of light increases (and frequency decreases) as a light source moves away from an observer.