Quiz 1 Flashcards
Order of the planets
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
What does our solar system contain?
The sun, the eight planets, the dwarf planets, comets, and asteroids
What is an astronomical unit?
The average distance between the Earth and the Sun
Jovian planets
(Larger)
Jupiter, Saturn, Uranus, Neptune
Terrestrial planets
(Smaller)
Earth, Venus, Mars, Mercury
What is a planet?
A “large” object that orbits a star and shines primarily by reflecting light from its star.
What did ancients call planets?
Wondering stars
What is the moon?
A natural satellite that orbits around a planet
What is the sun?
The star that is at the center of our solar system. The largest object in the solar system. All other objects orbit around the sun.
Why was there discussion about Pluto being a planet?
In 2005, an object larger than Pluto was discovered, Eris. Eris has a moon which allowed us to calculate its mass which is 27% more massive than Pluto. Pluto had weird orbit, so did Eris.
How was it decided what Pluto is not a planet?
It was voted on my the IAU in Prague in 2006. Aprox. 400 voted
What does the IAU?
International Astronomical Union
What are the three criteria for a planet? As of 2006
1) A body that orbits the sun
2) Has a mass that is great enough to reach hydrostatic equilibrium (meaning that it is nearly round)
3) as cleared the neighborhood around its orbit. This means that there are no longer any large bodies near the planet, that is unless they are under its gravitational pull
What is Charon?
The largest moon of pluto.
More about Charon…
Half the diameter of Pluto
Center of mass is outside of Pluto
Is double planet
Pluto has five moon
Nix, Styx, Hydra, Charon, Kerberos
What is a dwarf planet?
a) is in orbit around the Sun,
(b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape,
(c) has not cleared the neighborhood around its orbit, and
(d) is not a satellite.
What are the five dwarf planets?
Ceres, Pluto, Eris, Makemake, Haumea
How many planets exist outside the solar system?
Aprox. 4,000
What are stars made of?
Hydrogen and Helium. They generate energy through nuclear fusion.
What is a solar mass?
The mass of the sun. Scale rages from 0.1 to 100 solar masses.
The evolution of a star
Stars are born
Stars live
Stars die
What is a galaxy?
Galaxies are massive gravitationally bound systems of stars and stellar remnants, gas, dust, planets, and dark matter
What is dark matter?
Dark matter is matter that you can’t see but whose gravity affects visible matter and background radiation
