Space quiz Flashcards
What is an Astronomical Unit
Astronomical Unit (AU) - distance from Earth to Sun
What is a light year
Lightyear - distance light travels in one year
- What is cosmology?
The study of the universe
- Who first discovered that our universe is expanding? What did he notice?
Edwin Hubble
Galaxies seemed to be flying further and further apart
- What does the expansion of the universe imply? What does this refer to at the time?
Everything should have started with the monumental explosion from an indefinitely hot, small point.
This is known as the “Big Bang”
- What happened after the Big Bang?
The universe cooled down to form stars and galaxies we see today.
- What is a particle accelerator?
A machine that smashed together subatomic particles at greater energies
- What is the Big Bang Theory? Summarize it.
It is an explanation of the early development of the Universe.
According to this theory the Universe expanded from an extremely small, extremely hot, and extremely dense state. Since then, it has expanded and become less dense and cooler.
- When did the Universe begin?
13.7 billion years ago
- What were the two major scientific discoveries that provide strong support for the Big Bang Theory?
Hubble’s discovery in the 1920s of a relationship between a galaxy’s distance from Earth and its speed; and the discovery in the 1960s of cosmic microwave background radiation
- What is the expanding universe?
Space between galaxies is increasing – they’re getting further apart as space itself expands
- What is Hubble’s Law?
The farther away objects are from Earth, the faster they are moving away from us.
- What is cosmic microwave background radiation (CMBR)?
Leftover heat radiation from the Big Bang.
- Who discovered cosmic microwave background radiation (CMBR)?
Arno Penzias and Robert Wilson
- According to the cosmologist, what may have caused the acceleration of the space expansion?
Dark energy
- The Big Bang was followed by ‘inflation’. What is ‘inflation’?
A period of very rapid expansion and cooling
What is the Solar Nebula Theory (the most widely accepted theory)
A large nebula condensed into a star, but in the process also formed an outer ring of material which became the planets.
What is the 2) Catastrophic Theory
A star collided with the Sun and the debris formed the planets.
What does the Solar nebula theory suggests the following steps in solar system formation:
- About 5 billion years ago, a massive cloud of gas
and dust (nebula) begin to contract through gravity, and forms masses
2.Temperature and pressure in the center increases
3.Center becomes a protostar (hot, condensed object)
- Nuclear fusion occurs between hydrogen nuclei in the center
Sun begins to form (start shining)
Remaining materials (nebula) around the sun lump together to form 5. planets
What is Supporting Evidence for the Solar Nebula Theory
Planets orbits (revolve) the Sun in the same direction
Most planets orbit (revolve) the Sun in the same plane
Most planets rotate in the same direction
- Why did the protoplanets travel around the Sun in the same direction?
Because they all formed from the same cloud of gas and dust
- Why did the rocky planets formed closer to the Sun whereas the gas giants formed in the cooler outer region of the solar system?
Because the heat and the solar winds caused by the Sun swept the lighter gases further out
What is a lunar eclipse and when does it happen?
When Earth’s shadow covers the moon
What is a Solar eclipse
When Moon’s shadow covers the Earth
What is the Umbra
a region of complete shadow, which a complete eclipse will occur
What is the penumbra
A fringe region of partial shadow, which a partial eclipse will occur
- Where do total eclipses occur?
Darkest part of the shadow - the umbra
- In the lighter part of the shadow, penumbra, what type of eclipses occur?
Partial eclipses
- Why do we ever get eclipses?
Because there are 2 points where the Moon’s orbit crosses the Sun’s plane, called nodes.
As the Earth orbits the Sun, Earth travels to the nodes twice a year.
- In a total solar eclipse, why is it possible for the Moon to completely cover the Sun from the vantage point of some place on earth?
Because even though the Sun is 400x larger than the Moon, it is also 400x further away, so the Moon can cover the Sun.
- In the far future, why will Earth only get annular solar eclipses?
Because the Moon is moving away from the Earth about 1.5 inches every year.
- Why are we more likely to see a total lunar eclipse compared to a solar eclipse?
Because a total solar eclipse only viewable by 0.5% of Earth’s surface, and totality lasts max 7.5 min.
But a total lunar eclipse viewable by anyone on night side of Earth, and can last 1 hour and 40 min.
- During the total lunar eclipses, why does the Moon often turn red?
Because gas molecules in air scatter shorter blue wavelengths of light, while longer red wavelengths pass to the Moon.
What are tides?
Tides are caused by gravatational
Large object (moon) attracts water closer to it, making the tide higher
Each day, there are 2 high tides and 2 low tides
