Quiz 1 Flashcards
What is the source of energy of a star? Give an example of a star?
A nuclear reaction called fusion that happens in the core of a star. Nuclear reactions are different from chemical reactions. Ex: the sun, Sirius, Polaris
What does IAU stand for?
International Astronomical Union
What is the solar system?
It is composed of the sun, the planets, and various other fragments of rocks
What is our galaxy called?
The Milky Way
How many stars (approximately) does a galaxy contain?
Between 100 and 400 billion
Give the order of which term contains the other:
- galaxies, universes, planets, solar systems
Universe > galaxies > solar systems > planets
What does the moon orbit around?
Earth
How long does the cycle of lunar phases last?
27 days long
How far is the moon from earth?
384 400km
Whose footprint is photographed on the earth?
Buzz Aldrin, Apollo 11 astronaut
How many people have stepped on the moon?
12 people
What is the atomic number of a chemical element?
The number of protons in the nucleus of an atom
What two elements have the lightest atoms?
Hydrogen and helium. They are the most abundant elements in the universe
What is most of earth’s atmosphere made of?
Nitrogen and Oxygen
What is the earths crust made of?
Two thirds of the atoms: oxygen
One third of the atoms: silicon
What determines the colour of a rock? (Element-wise)
Rocks rich in magnesium and iron have a darker colour, and vice versa
What is lunar surface made of?
Same things as earth. Oxygen and silicon
What are two types of lands on the moon?
Highlands: lighter surfaces
Lowlands: darker surfaces filled with billions of years old solidified iron and magnesium rich lava.
What is the ISS? What is its distance from Earth? How long does it take to complete an orbit?
International Space Station. It is at an altitude of about 400km above the surface of the earth. It completes one full orbit every 92 minutes
What does JWST stand for?
James Webb Space Telescope
What is Antares?
A red supergiant star
What is Olympus Mons?
The highest volcano in our solar systems, located on Mars.
How do chains of volcanic islands form?
When a tectonic plate continuously moves over a hot spot located below the plate
Why is Olympus mons that enormous?
Because there is no motion in the tectonic plate to carry that mountain past the hot spot located below the plate
What is Jupiter
5th planet from the sun, largest planet in our solar system, has the Great Red Spot (giant storm)
What is Ida and Dactyl
Two asteroids in the asteroid belt. Ida is Montreal sized. Dactyl is four times that of Dawson.
What is Fomalhaut b?
One of the earliest discovered extrasolar planets, in orbit around star Fomalhaut
What is extrasolar planet?
Any planet outside our solar system
What is the Crab Nebula (M1)
A nebula (cloud of gas) that is an SNR
What does SNR stand for?
Super Nova Remnant. The supernova was witnessed in 1054
What are the Pleiades?
Also known as M45, the 7 sisters. It’s an open cluster of stars.
What are the two star cluster types?
Open and globular
What does the HST stand for?
Hubble Space Telescope
There is an image called The Hubble Ultra Deep Field by HST. What is its field of view? What is the exposure time? What is the object shown?
FOV: 3.10 * 3.10 arc minutes
Exposure time: 22 days
Objects: furthest away galaxies
There is an image called Pale Blue dot. Where was voyager 1 when it captured it? What are the object shown?
Where: about 6 billion km away from earth on the edge of solar system
Objects shown: Earth
HERE WRITE SOME SCIENTIFIC NOTATION QUESTION
Scientific notation answers here
How to convert km to m?
1 km = 1000m = 1 km * 1000
ex:
5km = 5000m
What is the width of Montreal?
50km
What is the radius of earth?
6400km
What is the radius of the earth in comparison to the moon?
3.5 * radius of the moon
What is radius of the sun?
109 * radius of earth / 10* radius of Jupiter
What is radius of Jupiter ?
10.9 * radius of earth
What is the brightest star?
Sirius
What is Orion? What is Orion’s left shoulder?
A constellation. It is Betelgeuse, a star
What is the largest known star and what is its radius compared to the sun?
UY Scuti. It has a radius between 1500 to 2000 times that of the sun
What is an astronomical unit? (AU)
It is the distance of the earth-sun. No need to memorize how many meters.
What is the radius of the solar system in AU?
About 40 AU
What is the parsec ? (pc)
A distance unit bigger than AU.
What is kpc and mpc?
Kpc ( kilo) = 1000 parsecs
Mpc (mega) = 1 000 000 parsecs
What is apparent size?
Called “angular sizes” and measured in angles
Complete
Completr
How can you compare degrees, arcminutes, and arcseconds? Give three formulas.
1 degree = 60 arcminutes
1 arcminutes = 60 arcseconds
1 degree = 3600 arcseconds
How do we measure distance to nearby stars?:
using the parallax method
What is the light year?
A distance unit. It is the distance that light travels in vacuum in one year.
How far away are the sun and alpha centauri in light years? What does this mean?
Sun: 8 minutes
Alpha Centauri: 4 years
This means (for the sun) it takes 8 minutes for light to reach us, so we the sun as it was 8 minutes ago
Give three notable stars
Sirius, Polaris, and alpha centauri
What is Sirius?
The brightest star in the night sky. It is about 8.61 ly away
What is Polaris?
The North Star. It indicates where north is. It’s about 430 light years away
What is alpha centauri?
The closest star system to us. It has three stars close to each other. It’s about 4 light years away. The faintest star Proxima Centauri is the closest to us.
How to do unit conversion?
Answers HERE
What is the hazy band in the sky? How many lightyears is it in diameter?
The Milky Way. 80 000ly.
What is extinction?
The absorption, scattering, and reddening of star light due to the interstellar gas and dust
Give six facts about the milky way?
1- it is a barred-spiral galaxy
2- number of stars: 100 thousand million
3- diameter: 80 000ly approximately
4- average thickness of the galactic disk: 1000ly
5- the solar system is located 25 000ly from the center of the galaxy
6-the sun revolves once around the center of the milky way every 200 million years
Identify parts of the galaxy?
The disk - long stretch in middle
The bulge - the middle circle
Halo of globular clusters - circles
What 6 things does a galaxy contain?
1- stars
2- the interstellar medium – thin mixture of gas and dust, with some denser parts called nebulas
3- cores of dead stars
4- failed stars (“brown dwarfs”)
5- one super massive black hole at certain of galaxy
6- dark matter
Give an explanation of an open cluster. How far apart are these star clusters?
It is a group of up to a few thousand stars that formed together from the same nebula. They are found in galactic disk.
-Stars in the cluster are loosely bound to each other in gravity
-the stars in the cluster are all approximately at the same distance from us
-the most famous open cluster is the pleiades
give explanation for globular clusters.
A globular cluster is a spherical collection of hundreds of thousands of very old stars that also formed at the same time. They are very tightly bound together.
-they are found in the galactic halo, and they orbit the galactic center
-there are about 150 known globular clusters in halo of milky way galaxy
What is the interstellar Medium (The ISM)
the gas and dust that fills the space between the stars in a galaxy. it consists of an extremely diluted mixture of gas (atoms, ions, molecules) and dust grains
average density of the ism is one atom per cm cubed
-the gas is 90% hydrogen, 9% helium
What is an asterism?
is an observed pattern or group of stars in the sky
What is an interstellar cloud?
denser than average region of the ISM its composition varies
What is a molecular cloud?
interstellar cloud that contains some molecules. stars form inside here
what is nebula
synonym for interstellar cloud
give two exxamples of nebulas
the eagle nebula and the orion nebula
What is parallax?
the apparent shift of the position of an object, relative to a distant background due to the observer switching positions
What is the formula for distance to the star in parsec?
distance to the star = 1/P
