Space Quizzes (History, Stars, etc.) Flashcards
What observations by Galileo rejected the Aristotelian geocentric model of the universe?
Observing four moons of Jupiter
Which one is the experimental confirmations for predictions of the general relativity?
The precession of the perihelion of Mercury
Who was the first to explain by mathematical methods the universal laws governing the motion of the planets?
Kepler
What makes Charles Darwin’s work on evolution so unique and convincing?
The volume and strength of the data and using scientific methods to understand the data
What happens when anti-matter and matter interact with each other?
They annihilate each other, resulting in the conversion of matter to energy.
Which statement is wrong?
- Electrons are moving around the nucleus.
- Atoms consist of electrons, protons, and neutrons.
- Free neutrons decay to protons emitting an electron and a neutrino.
- Protons and electrons have three quarks each
Protons and electrons have three quarks each
The curvature of the universe is…
Flat
Which of the following is wrong?
- The disorder in a physical system is called entropy
- There is more tendency for a physical system to evolve to higher state of disorder.
- The entropy of a system is an invariant quantity over time.
- There is more tendency for a physical system to evolve to higher entropy.
The entropy of a system is an invariant quantity over time.
Electrons and positrons collide and produce…
Photons
Which one is not a conservation law?
- Conservation of angular momentum
- Conservation of momentum
- Conservation of energy
- Conservation of entropy
Conservation of entropy
Two electrons mainly interact through the…
Electromagnetic force
Which of the four fundamental forces keeps atomic nuclei from falling apart?
Strong nuclear force
Deuterium is formed by the combination of…
A proton and a neutron
Which of the following is not part of Big Bang Nucleosynthesis (formation of elements heavier than Hydrogen isotopes)?
- The fusion of a neutron with Deuterium to create Tritium
- Proton-Neutron capture
- The synthesis of elements to form 7Li or 7Be (each with an atomic number of 7)
- The fusion of a neutron with 4He to create 5He
The fusion of a neutron with 4He to create 5He
What does the Big Bang Theory predict?
It predicts that about 75% of the mass of the baryonic matter ended up in Hydrogen with about 25% in He. Also, it predicts that about 380,000 years after the big bang, radiation decoupled from matter and the universe had a temperature of about 3000 Kelvin. Also, it predicts that temperature drops as the Universe expands.
What is not true about the Cosmic Microwave Background?
- It is the leftover radiation from the Big Bang.
- Since decoupling, its temperature has dropped from 3000 K to a current value of about 3K.
- It was first discovered by Penzias and Wilson in the 1940s.
- The slight density contrasts in it are the initial perturbations which eventually grew into galaxies and galaxy clusters).
It was first discovered by Penzias and Wilson in the 1940s.
What is the chronological order (first to last) of Dark Ages, Big Bang, and Reionization?
Big Bang, Dark Ages, Reionization
Describe the epoch of reionization.
High energy light, produced by early stars and galaxies, hit atoms and removed electrons from them, making the universe transparent.
What is the order of the early stages of the formation of stars: Hot or cold molecular gas, protostar phase, gravitational collapse, formation of disk?
Cold molecular gas, gravitational collapse, formation of disk, protostar phase.
Describe the Cosmic Dawn.
Occurs 510^8 years after the big bang.
Lasts about 500-60010^6 years.
Refers to the era of reionization.
Is caused by the birth of young stars that produce UV photons.
What is the theory of inflation?
Space underwent a rapid expansion in a very brief period in the early universe.
What is the approximate age of the universe?
10 Gyr
Which force is not described by the standard model?
Gravity
Why do we call dark matter “dark”?
It emits no or very little electromagnetic radiation of any wavelength.
Based on current evidence, a supercluster is most likely to have formed in regions of space where…
The density of dark matter was slightly higher than average when the universe was very young
How are rotation curves of spiral galaxies determined beyond radii where starlight can be detected?
Through observations of the 21 cm line of atomic hydrogen
What is meant by “dark energy”
The agent causing the universal expansion to accelerate
I observe a galaxy that is 100 million light-years away: what do I see?
The light from the galaxy as it was 100 million years ago and it is redshifted.
If the universe is open…
Material will get further and further apart, and eventually no new stars will form.
How does gravitational lensing tell us about the mass of a galaxy cluster?
Using Einstein’s general theory of relativity, we can calculate the cluster’s mass from the precise way in which it distorts the light of galaxies behind it.
How old is the universe and how do we know?
14 billion years old; the expansion of the universe appears to have started about this long ago.
What are the 3 statements of critical density?
- critical density is greater than 1 = the universe will recollapse.
- critical density is less than 1 = the universe will expand forever.
- critical density is equal to 1 = the density of th universe is critical;stable
What are 3 examples of dark matter? What is one example of something that is not dark matter?
The planet Uranus, an isolated black hole, and a weakly interacting massive particle are examples of dark matter. The star Sirius A is not an example of dark matter.
Which is not a type of galaxy? S0, SBc, E0, or Ir?
Ir is not a type of galaxy
Describe Population I stars and their location
Population I stars are younger and bluer than other stars and they are found mainly in the outer regions of galaxies.
The minimum temperature for Carbon fusions is higher or lower than the temperature needed for Helium fusion?
Higher
In general, the heavier elements require higher or lower temperature to start fusion?
Higher
Where have elements heavier than iron been produced?
Supernovae
What is the main source of the heat and light from stars?
Nuclear reaction
Where can elements heavier than carbon be produced?
Core of the massive stars
What are 3 stages of a massive star? What is one stage that is not part of the massive star evolution?
Neutron star, red supergiant, and black hole are stages of a massive star evolution. Black dwarf is not a stage in the massive star evolution.
What happens after the hydrogen-burning phase in a low mass star?
The core collapses
What is the composition of the gas between stars?
98% Hydrogen and Helium, 2% heavier elements
What is the definition of the escape velocity?
The minimum speed needed for a free object to escape from the gravitational influence of a massive object.
Describe a white dwarf. What is one thing that does not describe a white dwarf?
A white dwarf has degenerate material, it is very dense, and it has a surface temperature of about 25000 K. A white dwarf does not have a very large radii.
Describe a black hole.
Light cannot escape from a black hole. A black hole can have spin. A black hole does not lose its mass when there is a companion star close to it. As gas around a black hole spirals into the black hole, it emits X-ray.
High mass stars most likely make what? Low mass stars turn into what?
High mass stars most likely make supernovae, and low mass stars most likely turn into white dwarfs.
