P16 Space Flashcards
What is the Big Bang theory?
The theory that the universe began from a small singularity, which was extremely hot and dense
Name the plants in our solar system in ascending distance from the sun
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
What is a moon?
A natural satellite that orbits a planet
Describe how stars form
- Nebulae (clouds of dust and gas, which is mainly hydrogen)
- Gravity causes cloud of dust and gas to collapse
- Particles move faster, and temperature rises to millions of degrees Celsius
- This is a Protostar
- If the temperature becomes high enough, then hydrogen nuclei join and undergo fusion to form helium
- At this point, the Protostar has turned into a star
- Two opposing forces acting between the star (Gravity and fusion) keep it at equillibrium
What is meant by a star being at equillibrium?
When the force of gravity is balanced by the fusion energy, creating an EQUILLIBRIUM between the
gravitational collapse of a star and the expansion of a star due
to fusion energy.
What is a Main Sequence star?
A star that fuses hydrogen and helium in its core
Describe what happens to stars around the same size as the sun
- Hydrogen in the star begins to run out
- Outward force due to fusion
Describe what happens to stars much larger than the sun
- Eventually run out of hydrogen and leave the main sequence stage
- Expand into RED SUPERGIANTS
- Helium nuclei fuse to produce heavier elements (not past iron)
- Red supergiant stops carrying out fusion
- Red supergiant explodes (Supernova)
- Temperature now becomes high enough to produce elements heavier than iron
What is the heaviest element that nuclear fusion can produce?
Iron (NUCLEAR FUSION CANNOT PRODUCE ANY ELEMENTS HEAVIER THAN IRON)
How are elements heavier than iron produced?
In a supernova
What is a supernova?
The exploding of a red giant after it stops carrying out fusion
Describe what can happen the remains of a star after a supernova
It can turn into a neutron star - consisting of neutrons tightly packed together
or
It can from a black hole, with such a large gravity that not even light can escape
State the effect fusion has on the size of a star, and the temperature of its core
It causes the temperature to increase, and the size to remain the same
State one similarity and one difference between the orbits of a planet and a moon in our solar system
- They both have virtually circular orbits
- Moons orbit planets, planets orbit the sun
Satellite A and B are two artificial satellites in stable orbits around the Earth. Satellite A is orbiting closer to Earth in comparison to B. State the difference in velocities {4}
- Satellite A is orbiting faster than satellite B
- The closer the satellite is to the Earth, the stronger the gravitational force on the satellite is
- A larger instantaneous velocity is needed to balance it
- So satellite A will need to orbit the Earth faster than satellite B to remain in a stable orbit
