Download Unit 11 Vocabulary

Unit 11 Vocabulary
1. universe - the Universe is all of time and space and its contents. The
universe includes planets, stars, galaxies, the contents of
intergalactic space, the smallest subatomic particles, and all matter
and energy.
2. star – a large sphere of hydrogen gas, held together by gravity, that
is hot enough for nuclear reactions to occur at its core. Our Sun is the
closest star to Earth.
The Sun
3. protostar - a very young star that is still gathering mass from its
parent molecular cloud. This is the earliest phase in the process of a
star’s evolution.
4. main sequence star - stars that are fusing hydrogen atoms to form
helium atoms in their cores. Most of the stars in the universe are main
sequence stars – they are the stars that “twinkle.”
5. red giant star - a star that has exhausted the primary supply of
hydrogen fuel, and is in the last stage of its life.
6. red supergiant star - the largest stars in the universe in terms of
volume, although they are not the most massive. Betelgeuse and
Antares are the brightest and best known red supergiants.
7. white dwarf star – this is what stars like the Sun become after they
have exhausted their nuclear fuel. A white dwarf is very dense, and is
about the size of Earth.
Extra Credit if you can name the seven dwarfs. Write their names in
your notes. No, none of them are real stars like a white dwarf, they
are only Disney stars!
8. neutron star - Neutron stars are the smallest and densest stars
known to exist in the Universe. They can form from the gravitational
collapse of a massive star after a supernova.
9. black dwarf star - A black dwarf is created when a white dwarf star
becomes too cool and can no longer create large amounts of heat
and light. The star will dim and become black. We can’t confirm that
Black dwarfs exist.
10. black hole - a place in space where gravity pulls so much that even
light can’t get out. The gravity is so strong because matter has been
squeezed into a tiny space.
11. Nebula - a cloud of gas and dust in space. Some nebulae are
regions where new stars are being formed, while others are the
remains of dead or dying stars.
12. stellar nebula - a cloud of superheated gases and other elements
formed by the explosive death of a massive star. This is where stars
are made.
13. planetary nebula - form when a main sequence star grows into a
red giant and throws off its outer layers and the core collapses
DRAW this flow cart in your notes:
14. elliptical galaxy – these galaxies are elliptical shaped, and have
billions of stars, but little gas and dust between the stars. Most of its
stars are older stars.
15. spiral galaxy - consist of a flat, rotating disk with stars, gas, and
dust and a central concentration of stars, known as the bulge. They
contain middle-aged stars.
16. irregular galaxy – galaxies that have no regular shape. They
contain young stars.
17. barred-spiral galaxy - a spiral galaxy with a central bar-shaped
structure composed of stars. Our Milky Way Galaxy is this type.
18. luminosity – a star’s brightness
19. Hertzsprung-Russell diagram – a tool that plots each star on a
graph measuring the star's brightness against its temperature (color).
20. absolute magnitude – the brightness of a star as if it were 32.6 light
years from Earth
21. apparent magnitude – the brightness of a star as seen from Earth