aster bru Flashcards
(28 cards)
What is astronomy and what does it include?
The study of celestial objects: anything that exists outside of Earth.
This includes objects such as: Planets, Moons, Asteroids, Comets, Stars, Black Holes, Galaxies, and the entire universe as a whole
What is science?
Science is not a body of knowledge, It’s a method for obtaining and verifying knowledge about our universe.
“It is known that the model of the universe that we have right now is 100% correct.” True or false?
False. There are still things our model does not explain (for example, dark matter), but more importantly, in science, nothing is ever considered the absolute and final truth, and we are always ready to replace any model if a better one provides a better match to experimental data.
What is a scientific model called before it is verified experimentally?
A hypothesis.
What happens if the results of experiments disagree with the predictions of a scientific theory?
The theory is no longer considered correct, and we need to find a better one.
What is a challenge that astronomy has, which other sciences generally don’t have?
In astronomy, since we are studying objects that are extremely far away, we cannot do experiments in a lab. We can only observe these objects from afar using telescopes.
A famous astronomer wrote a paper with a new theory. The theory has not been tested experimentally, but the astronomer is VERY famous. Can we assume that the theory is correct?
No. While the astronomer may call this idea colloquially a “theory”, it is still just a hypothesis, and must be confirmed in multiple experiments before it is considered correct (and even then, it could still be replaced with a better one later). It doesn’t matter how famous you are, you are never exempt from this rigorous scientific process.
What was the new class of astronomical objects predicted by Einstein’s theory of relativity?
Black holes.
Is the number 3×107 smaller or larger than the number 6×105?
Larger. The first number is 30,000,000 and the second number is 600,000, which is clearly smaller. In general, the number with the larger exponent will always be the larger number.
What is a light-year?
It’s the distance light travels in a year, or approximately 9.5×1012 kilometers.
“A fast race car can reach speeds of up to 10% of the speed of light.” True or False?
False. The speed of light is 300,000 kilometers per second. 10% of that is 30,000 kilometers per second. Have you ever seen a car that can travel 30,000 kilometers (around 9 times the distance from Toronto to Vancouver) in 1 second?
Which is longer, a meter or a kilometer?
A kilometer. A kilometer is equal to 1,000 meters.
I observed a supernova (an exploding star) in the sky this year. The distance to the supernova was 12,000 light-years. How long ago did the star actually explode?
12,000 years.
What does the Earth have that no other planet in the solar system has?
As far as we can tell, it is the only planet in the solar system where sentient life has evolved.
How many planets are in the solar system? Can you name all of them?
There are 8 planets. From closest to farthest from the Sun, these are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. To remember them, you can use the mnemonic: “Many Very Educated Men Just Screwed Up Nature.”
Which planet is the closest to the Sun? Which planet is the farthest away from the Sun?
Mercury is the closest, Neptune is the farthest.
What’s the difference between a planet and a star?
A star produces its own light, a planet doesn’t.
What is the closest star to the Sun? How far is it? How long does it take light from that star to get to us?
Proxima Centauri is the closest star, at 4.2 light-years away, which means light takes 4.2 years to get to us from that star.
“There are several million stars in the Milky Way Galaxy.” True or false?
False, there are hundreds of billions of stars in the galaxy.
Is the Sun at the center of the Milky Way Galaxy?
No, it is not. We are not the center of the universe! Our Sun is around 30,000 light-years away from the center of the Galaxy.
Have astronomers been able to take photos of the Milky Way Galaxy from outside the galaxy?
No, this is impossible, as it would require sending a spaceship thousands of light-years away from the galaxy. Even if we had the technology to do that, it would take thousands of years before we can receive the photos. We are only able to take photos of the Milky Way from the inside, since we are inside it.
Is Andromeda the nearest galaxy to us?
No, it is the nearest LARGE galaxy to us. There are smaller galaxies that are closer to us. (The nearest galaxy is called the Sagittarius Dwarf Galaxy.)
What is the name of the cluster of galaxies that the Milky Way belongs to?
The Local Group.
What is the name of the supercluster that this The Local Group cluster belongs to?
The Virgo Supercluster.
