Exploring The Universe

Question 1

What Is A Star?

Answer 1

A star is an astronomical object, that is a sphere of matter. It gives off heat and light, and is held together by its own gravity.

Question 2

What Is A Solar System?

Answer 2

A solar system consists of a star and natural objects travel in an orbit around this star.

Question 3

What Is A Galaxy?

Answer 3

A galaxy is a cluster of hundreds of millions of stars and planets, held together by gravitational forces.

Question 4

What Is Our Solar System?

Answer 4

Our solar system consists of one star - our sun, eight planets, dwarf planets, asteroids, comets, and the natural satellites of those planets.

Question 5

Why Is Light Year Used Instead Of Kilometre Or Meter?

Answer 5

Light year is the astronomical term scientists use because measurements like kilometres or meters are unrealistic. The distance in space is too large.

Question 6

Be Able To Calculate The Conversion Between Lightyears, Meters, And Kilometers

Answer 6

Multiply the numbers if you’re going from a bigger amount to a smaller one. And divide if you’re going from smaller to bigger. For example, lightyears to meters, you’d be multiplying. From meters to kilometres you’d be dividing.

Question 7

What Is A Nuclear Fusion Reaction?

Answer 7

A nuclear fusion reaction is when two light nuclei merge to form one dense nucleus. The energy that main sequence stars release is powered by nuclear fusion It involves hydrogen nuclei in the core of a star.

Question 8

How Does Nuclear Fusion Produce Energy In The Core Of A Main Sequence Star?

Answer 8

Nuclear potential energy is converted into different types of energy. For example, light energy. The energy formed in a star is the result of mass being lost as hydrogen fuel undergoes fusion. (It’s important to note that mass and energy are interchangeable.)

Question 9

What Is Absolute Brightness Related To?

Answer 9

Absolute brightness is related to the mass of a star. This can be calculated by using the equation: b is directly proportional to 1 divided by D squared.

Question 10

What Is Absolute Brightness Is Related To?

Answer 10

The greater the absolute brightness of a star, the greater the mass. The more massive a star is, the greater the gravitational force, as its core pushes the hydrogen together and fuses quicker. This results in more energy being released per second.

Question 11

What’s The Difference Between Apparent And Absolute Brightness?

Answer 11

Apparent brightness is the luminosity of a star as seen from Earth. Absolute brightness is the amount of energy released by the star per second.

Question 12

Which Stars Are Cool And Which Are Hot Depending On Their Colour?

Answer 12

Cool stars are red and hot stars are blue.

Question 13

What Relation Does Wavelength And Temperature Have In Stars?

Answer 13

Using Wein’s Law, the tip of the wavelength determines the colour of a star.

Question 14

What Is A Nebula?

Answer 14

A nebula is a region of intergalactic clouds of dust of gas.

Question 15

What Is A Protostar?

Answer 15

a protostar occurs when the gas of a nebula condenses. It loses gravitational potential energy and gains kinetic energy. This raises the temperature of the atoms, which creates a protostar.

Question 16

What Is A Red Giant?

Answer 16

A red giant is a luminous giant star, that has a low to medium mass. It occurs in the late phase of a star’s life. The star is inflamed, making the radius large and cool (expanding and cooling).

Question 17

What Is A White Dwarf?

Answer 17

A white dwarf is the final stage for a low to medium-mass star. It’s a small star, that’s usually the size of a planet but has the mass of our sun. A white dwarf forms when a star has used all of its nuclear fuel up, and pulls of its layers in a planetary nebula. The remaining core is a white dwarf.

Question 18

What Is A Supernova?

Answer 18

A supernova is one of the later stages of a high-mass star. The energy that is emitted during a supernova briefly outshines its entire galaxy, before fading from view. During a supernova, a star will expel almost - if not all of its energy. The energy travels at a speed of up to 30,000 km/s - which is 10% the speed of light.

Question 19

What Is A Red Supergiant?

Answer 19

A red supergiant occurs in one of the last stages of a large mass star’s life. They are cool and large stars, but not always the most massive. By the end of their lives, red supergiants have lost a lot of their original mass.

Question 20

What Is A Neutron Star?

Answer 20

A neutron star is the last stage of a large-mass star. If it’s three solar masses or below after a supernova, it’ll become a neutron star. The core after a supernova remains, however, it’s extremely dense. Protons and electrons are squeezed together by gravity. This makes neutron clusters. Without a lot of empty space in an atom, the star is very dense.

Question 21

What Is A Black Hole?

Answer 21

A black hole is one of the two endings for a large mass star. If it’s above three solar masses after the supernova, then it’ll become a black hole. The remaining part of the star (the core) is crushed into a small, dense object, called the singularity. Gravitation forces around a black hole are so strong that not even light can escape.

Question 22

What Are The Alternate Life Cycles Of Stars Depending On Their Mass?

Answer 22

If a star is up to eight solar masses, it’s classed as a high mass star. This means it’ll become a red supergiant, and go through a supernova. If, after the supernova, it’s above three solar masses, it’ll become a black hole. If it’s three or below, it’ll become a neutron star. If the star is up to 8 solar masses, it’ll become a red giant, go through a planetary nebula, and turn into a white dwarf.

Question 23

What Is The Big Bang Model Of The Universe?

Answer 23

The Big Bang model of the universe is the most accepted idea of how the universe began. It claims that the universe expanded and cooled very rapidly at the beginning of its life, from a hot, concentrated, dense piece of matter.

Question 24

What Are The Two Pieces Of Evidence That Support The Big Bang Theory?

Answer 24

The two pieces of evidence to support the Big Bang are the CMB (cosmic microwave background radiation) and red shift.

Question 25

What Is The Evolution Of The Universe As It Expanded And Cooled?

Answer 25

Electrons, protons, and neutrons formed from some of the energy, as it was converted into mass. The remaining energy was in the form of electromagnetic radiation. As the universe continued to expand and cool, small, gaseous atoms like helium and hydrogen formed. The matter that was forming was denser in some places than others. In the denser places, gravitational forces squeezed particles of matter together and made stars and galaxies.

Question 26

What Does The Term Accretion Mean?

Answer 26

Accretion is the process of growth of a body, by gathering more matter due to gravitational forces. This helps to form stars and galaxies.

Question 27

How Does Accretion Relate To The Formation Of Stars And Galaxies?

Answer 27

Accretion relates to the formation of stars and galaxies because in spaces where matter was denser, gravity would squeeze the particles of matter together and create stars and galaxies.