Unit 5 Astronomy

what is the approximate age of the universe

14 billion years old

How many stars are in the Milky Way?

200-400 billion

about how far is the sun from the center of the milky way

26,000- 27,000 light years

suppose we receive a radio message from a civilization around a star about 40 light years from earth? if we rely right away how long will it be between the time it they sent the message and the time they receive our reply

80

quasar

A distant galaxy with a black hole at its center

globular cluster of galaxy

A globular cluster galaxy is a large grouping of lots of other stars. Globular clusters are round and densely packed with stars, and some of which may contain more that a million stars.

barred spiral galaxy

A spiral galaxy with a central bar-shaped structure composed of stars.

why did the big bang not produce heavier elements

By the time helium could survive, the temperature had become too low for heavier elements to form.

Why are Cepheid variables important?

Cepheids variables are pulsating stars whose pulsation periods are directly related to their true luminosities. Therefore they can be used as distance indicators.

Galactic Disk

Flattened region of gas and dust that bisects the galactic halo in a spiral galaxy. This is the region of active star formation.

The most abundant element in the universe is

Hydrogen

bulge of a galaxy

The central portion of a spiral galaxy that is roughly spherical (or football shaped) and bulges above and below the plane of the galactic disk.

What recent series of discoveries has made astronomers more optimistic about our prospects of finding life out there?

The discovery of planets around thousands of stars in our galaxy

What is Hubble's Law?

The recession velocity of a galaxy is directly proportional to its distance from us.

Olber's paradox is an apparently simple question, but its resolution suggests that the unit is finite in age. what is the simple question posed by Olbers paradox?

What is a he sky dark at night?

spiral galaxy

a galaxy whose arms curve outward in a pinwheel pattern

halo (of a galaxy)

a spherical distribution of globular clusters, isolated stars, and dark matter that surrounds a galaxy

What did the Urey-Miller experiment find

amino acids were created in a test tube

who discovered that andromeda nebula was really the andromeda galaxy

edwin hubble

true or false: stars continue to form in the halo of our galaxy today

false

true or false: the hubble galaxy classification ( know as the tuning fork diagram) shows the evolutionary progression of the life cycle of a galaxy

false

where are most globular clusters found

halo

earlier in history of the universe it was..

hotter

Elliptical Galaxy

huge galaxy that is round or oval in shape

What is the Fermi Paradox?

if extraterrestrial life is common, why has some form of intelligent life in the galaxy not communicated with us or visited us?

Nucleus of a Galaxy

in the center of a galaxy

galaxy r is 100mly away from us. galaxy q is 80mly away from us light from which galaxy is what

light from r is more redshifted

the "habitable zone" is a region in a star system where

liquid water could exist on planets

what will the galaxy be called when the milky way collides with andromeda

milkwmada

what experiment models conditions in early earth atmosphere

miller and urey

the electromagnetic force is stronger than gravity. why is it over powered by gravity on a large scale?

most objects are electrically neutral

where does most star formation occur in the milky way today

spiral arms

where does new star formation take place in the milky way

spiral arms

Four fundamental forces of nature

strong nuclear force, weak nuclear force, electrostatic forces, gravitation

four fundamental forces

strong, gravity, electromagnetic, weak

In the early 1950's, Stanley Miller and Harold Urey conducted a series of pioneering laboratory experiments involving simulations of the early Earth. What did these experiments reveal?

that under the conditions on the early Earth, they could synthesize some of the building blocks of life in a laboratory

which of the following events in cosmic history is most recent?

the formation of life on Earth

what is the big bang theory

the idea that all matter and energy in the universe began in an unimaginably dense state, and then space itself began expanding

the drake equation allows astronomers to estimate what

the number of civilizations out among the stars with which we might communicate

true or false: the observed composition of ordinary matter in the universe roughly 75 percent hydrogen and 25 percent helium by mass closely matched theoretical predictions based on the big bang theory.

true

What two quantities did Edwin Hubble compare for a sample of galaxies to discover the expansion of the universe?

velocity and distance

what is a good statement about life elsewhere in the universe is best supported by current evidence

we have no definitive evidence about life around other stars at this time

from a scientific perspective which of the following statements about life elsewhere in the universe is best supported by current evidence

while we have evidence of the building blocks of life elsewhere in the universe, we have no definite evidence about life around other stars at this time