Astronomy

Question 1

What is astronomy? What is the difference between astronomy and astrology?

Answer 1

Astronomy is the scientific study of the universe.
It studies celestial objects such as planets, nebulae and stars.

Astrology is the study of how celestial objects can affect people on earth. It predicts future events and is a pseudoscience meaning that it is not scientifically proven.

Thus, astronomy uses real scientific research while astrology is a belief which is not backed up by scientific evidence.

Question 2

What is plasma?

Answer 2

Plasma is a state of matter that is formed when electrons are stripped from atoms in a gas, due to an extremely high temperature. It contains ‘free electrons’ and has charged particles unlike gases, which have no charge whatsoever.

Question 3

What is a star? What are stars mostly made of?

Answer 3

A star is a giant ball of hot glowing plasma. It is mostly made of Helium and Hydrogen

Question 4

Define nuclear fusion

Answer 4

Nuclear fusion is when two nuclei combine to form a single nucleus. During this process, they release massive amounts of energy.

nuclear fusion is used to obtain almost unlimited energy.

Question 5

Why does nuclear fusion release energy?

Answer 5

Nuclear fusion releases energy when two nuclei combine to form one single nucleus, which is less than the mass of the two original nuclei. This leftover mass then becomes energy.

Question 6

Why do stars glow? What is the process?

Answer 6

Stars have very high temperatures. This temperature causes nuclear fusion to occur, converting hydrogen to helium. During nuclear fusion, leftover mass from the combination of two nuclei is converted to energy, which then becomes the visible light that we see whenever we look at stars.

Question 7

What is the difference between nuclear fusion and nuclear fission?

Answer 7

Nuclear Fusion is when you combine two or more atoms into one larger one, whereas nuclear fission is the opposite, where you split an atom into two or more smaller ones.

Question 8

How many hydrogen atoms are needed to convert to one helium atom in nuclear fusion

Answer 8

4 hydrogens are needed to fuse into 1 helium atom during nuclear fusion

Question 9

What is electromagnetic radiation?

Answer 9

Electromagnetic radiation is light that travels by oscillation in waves, at a constant speed while carrying energy.

Question 10

What is the difference between apparent magnitude and absolute magnitude?

Answer 10

Apparent magnitude measures how bright a star appears from the earth, while the ABSOLUTE MAGNITUDE is the proper more accurate measurement of how bright a star is. Absolute magnitudes measure it as if all stars are at the same distance from the sun

Question 11

What is the brightest star in the sky?

Answer 11

Sirius

Question 12

Why does the moon glow in the night sky? What about planets?

Answer 12

The moon reflects the sun’s light, which then shows its glowy characteristics. The same goes for planets.

Question 13

What is a planet?

Answer 13

A planet is a celestial object that ORBITS AROUND THE SUN

Question 14

What is the difference between stars and planets?

Answer 14

Stars produce their own light while planets do not. (They reflect light from the sun or other stars)
Stars are also made up of hydrogen and helium while planets consist of solids, liquids and gases

Stars have very HIGH TEMPERATURES. Planets do not

Question 15

What determines how fast a star uses its nuclear fuel in fusion reactions?

Answer 15

The mass of the star. The mass of the star determines its lifetime,, its gravitational pressure and the rate of nuclear fusion

Question 16

Why are stars very hot? How is the colour of a star determined?

Answer 16

Stars are very hot because they burn their fuel really quickly.
The colour of a star is determined by surface temperature. The smallest stars tend to be red and cool, while the biggest stars are blue and hot.

Question 17

What is the temperature of the sun in celsius?

Answer 17

5500 °C

Question 18

What is luminosity?

Answer 18

Luminosity is the amount of light emitted by an object at a point in time

Question 19

What is the Hertzsprung Russel (HR) Diagram?

Answer 19

The HR shows the relationship between a star’s temperature and its luminosity. The temperature is measured on the x-axis while the luminosity is on the y-axis. It also investigates the properties of a collection of stars.

Question 20

What is a nebula?

Answer 20

A nebula is a massive cloud of dust and gas. Nebulae are formed generally from the explosion of a star such as a supernova.

Question 21

What is a supernova

Answer 21

A supernova is a MASSIVE explosion of a star

Question 22

What is a white dwarf?

Answer 22

A white dwarf is a ‘dead star’ because atoms no longer fuse to give the star energy. They have exhausted their nuclear fuel and only shine due to the immense temperatures.

Question 23

What is the difference between the universe and the galaxy?

Answer 23

The universe refers to everything that exists, including galaxies. However, galaxies are just massive clusters of stars held together by gravity.

Question 24

What is a light year? Why do we use light years as a unit of measurement within the universe?

Answer 24

A light year is NOT A MEASURE OF TIME. It is the distance that light travels in one year.

A light year is 9.46 x 10^12 KM

‘light years’ are used because the distances we deal with in space are immense. Light years are more simple and easier to convert to and it is also known that the speed of light is constant within our universe, meaning that it is highly accurate.

Question 25

Our sun is 8 light minutes away from the earth. This means that its light takes 8 minutes to reach us, travelling at the speed of light.

Answer 25

yes

Question 26

What is stellar parallax?

Answer 26

Stellar Parallax is the shift in the position of a nearby star when seen from two different places in the Earth’s orbit. An example of stellar parallax is when you close one eye and look at your thumb while doing the same thing with your other thumb. The location will change depending on how you look at it and from which eye.

Question 27

What is the purpose of stellar parallax? How do you calculate it and what is the formula?

Answer 27

Stellar parallax is used to measure the distance to nearby stars.
Because even the nearest stars are many light years away, astronomers use a larger unit of distance called the Parsec \

One parsec is equal to 3.26 Light Years.
The formula is

d = 1/p

where ‘d’ stands for distance (in parsecs) and the ‘p’ stands for Parallax angle, which is in arc seconds.

*An arc second is an ANGLE not a measure of Time

Question 28

What is one arc-second equivalent to?

Answer 28

One arc second equals to an angle of 1/3600 of a degree

Question 29

How do you convert 1 parsec to light years?

Answer 29

1 parsec = 3.26 lightyears

Question 30

Do bigger stars have a longer lifetime than smaller stars?

Answer 30

No. Smaller stars last longer.

Bigger stars burn up their fuel supply much faster due to the larger presence of hydrogen.

A smaller star has less fuel but its rate of nuclear fusion is not as fast, which is why smaller stars have a longer lifetime than bigger stars.

Question 31

What determines the colour of light that a star emits?

Answer 31

The surface temperature of a star determines the colour of light they emit.

The hotter the star, the shorter the wavelength of light it will emit, thus making them blue or white-like, since these classify the short wavelengths in the spectrum.