Space, Celestial Objects And The Origin Of The Universe Flashcards

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1
Q

What is astronomy?

A

Astronomy is the science that deals with the universe beyond the earth’s atmosphere.

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2
Q

What are celestial bodies?

A

Naturally made objects outside the earth’s atmosphere are called celestial bodies.

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3
Q

Star Definition

A

A star is a celestial body that generates its own light and heat and consists of a mass of gas held together by its own gravity

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4
Q

Definition of a planet

A

A planet is a celestial body that is in orbit around a star.
It must be in orbit a star.
Have enough mass to form an almost round shape due to its own gravity.
Have cleared the region around its orbit of other celestial bodies.

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5
Q

Why is pluto no longer classified as a planet?

A

Pluto is no longer classified as a planet because it shares its orbit region with large objects that are not its moons, such as Eris, which is a similar size to Pluto. It also shares the region that it orbits with other asteroids and comets.
A planet should be the largest object in the region in which it orbits.

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6
Q

Definition of a moon and what is it?

A

Moon: a moon is a celestial body orbiting a planet.
Definition: A moon is a natural satellite of a planet.

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7
Q

What are asteroids and what is its definition?

A

Asteroids: these are small celestial bodies that orbit the sun. They do not have enough mass to cause enough gravity to keep an almost spherical shape like planets, they are also known as minor planets
Definition: an asteroid is a small rocky body orbiting the sun.

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8
Q

What is a comet and what is its definition?

A

Comets: these celestial objects are made of ice and dust. They orbit the sun however unlike planets, their orbit is not a circular path with the sun in the middle.
Definition: a comet is a dusty snowball which orbits the sun.

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9
Q

What is a solar system

A

A solar system is a group of planets, asteroids, comets and other celestial bodies that are in orbit around a star

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10
Q

What is the size of a solar system limited by ?

A

The size of the solar system is limited by the distance that the gravity of the star can attract other celestial bodies

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11
Q

What is referred to as the glue of the universe

A

Gravity is often referred to as the glue of the universe

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12
Q

What is a star, what does it generate and why, what percentage of mass of the solar system does it take up?

A

A star is a huge ball of gas able to generate its own heat and light. Our sun contains 99.9% per cent of the mass of the solar system. It generates its own heat and light due to the nuclear fusion of hydrogen.

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13
Q

How many planets are their in our solar system

A

8 mercury, Venus, earth, Mars, Jupiter, Saturn, Uranus, Neptune

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14
Q

Where is the astroid belt located

A

Inbetween mars and Jupiter

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15
Q

What exists at the edge of our solar system?

A

At the edges of the solar system there still exists a region of gas clouds called the Kuiper belt. It contains billions of lumps of rocky ice up to 8 km in diameter in orbit around the sun. They are called comets

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16
Q

What happens when the orbit of a comet is disturbed?

A

Occasionally the Comet’s orbit around the sun may be disturbed. They may begin to move towards the Sun.
The sun melts some of the ice and a tail of gas, ice and dust is formed.
The sunlight reflects off the tail when we see the comet.
The most famous is Halley’s Comet which has settled in orbit around the sun. It revolves around the sun every 76 years

17
Q

What is a Galaxy

A

A Galaxy is a large system of stars held together by Gravity and isolated from similar Systems by vast regions of space. Or solar system is part of the Milky Way galaxy

18
Q

What is the nearest neighbouring galaxy to us

A

Our nearest neighbouring large galaxy is called Andromeda

19
Q

What is in the outer space

A

Outer space is the empty volume that exists between celestial bodies.
It is not completely empty, but consists of a vacuum containing a low density of particles, mostly hydrogen and helium as well as dust and radiation

20
Q

What branch of astronomy deals with the formation of the universe

A

The branch of astronomy that deals with the formation of the universe is called cosmology

21
Q

Explain The Big Bang Theory

A

Astronomers believe the universe began in a big bang about 14 billion years ago. At that time the entire universe was inside a bubble that was much smaller than a pinhead. Is extremely hot and dense.
In a fraction of a second the universe grew from the size of a single atom to bigger than the size of a Galaxy. It kept on growing at a huge rate and it’s still expanding today.
Within the first few seconds protons neutrons and electrons are made. However it was too hot for these to mobile to form atoms.
After 300000 years the temperature had dropped enough to allow atoms of smaller elements for example hydrogen and helium to form. Giant clouds of atoms were pulled together by Gravity to make the first stars and galaxies.
After 5 billion years the first stars died and exploded and Forced new heavier elements into space, Gathering together and forming new stars, planets, planetary systems and galaxies.

22
Q

Explain evidence for the Big Bang

A
  1. There is Energy called cosmic background radiation remaining everywhere in space. Scientists Predicted this would be present if the big bang took place. It was detected in 1964 which strongly supported the Theory.
  2. It was discovered that the universe is continuously expanding. It was noticed that distant galaxies are moving away faster than nearby ones. This would suggest that all Galaxy started from one point.
  3. The Big Bang Theory predicts how much of certain elements should have been made in the early universe, and what we see in very distant galaxies and old Stars is just right. There is a dominance of light elements in the universe such as hydrogen and helium.