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Cosmos DVD episode 5: A Sky Full of Ghosts

Terms in this set (37)

time
Because even light travels at a finite speed, every star you can see in the sky is in a different place and _________.
the Sun
Light takes a little over eight minutes to travel here from
was 4 years ago
If we look at a star 4 light years away, we see it as it
refraction
Due to atmospheric __________ (the bending of light by the atmosphere), the sun is visible while actually below the horizon both at sunrise and sunset.
Earth's rotation on its axis
The motion of the Sun and Moon across the sky is an illusion caused by
distance
A light-year is a measure of
light year
One _________ is about 6 trillion miles (6,000,000,000,000).
time
The greater the distance is between you and an object you are observing, the farther back in _________ you are looking.
light
Galileo attempted to measure the speed of _________, but failed because it moves so fast.
nebula
When a star explodes in a supernova, it forms a (an) __________, a large cloud of interstellar dust and gas.
nebula
A __________ is a large cloud of interstellar dust and gas, frequently formed by an exploding star.
pulsar
A __________ is a rapidly spinning neutron star that emits beams of radiation that sweep through Earth's line of sight.
Milky Way Galaxy
The center of the __________ is about 27,000 light-years from Earth.
universe
Scientists estimate the age of the __________ to be at least 13 billion years old.
Big Bang Theory
One theory about the universe's creation, __________, posits that everything (matter, time, space) comes from an explosion a little over 13 billion years ago.
two or more stars
Many (perhaps most) stars we see are actually __________ revolving around the center of mass of that solar system.
binary system
A star system with two stars revolving around the system's common center of mass is known as a (an)
three stars
The closest star system to our solar system, Alpha Centauri, actually consists of
light
What moves at about 186,000 miles per second (300,000 km/s) in a vacuum?
electromagnetic spectrum
Visible light is just a tiny fraction of the
Gravity
__________ is always pulling you down.
no
There are __________ places in the universe where there is zero gravity.
hydrogen and helium
What two elements make up the vast majority of all stars?
Isaac Newton
The Universal Law of Gravitation was formulated by
electromagnetic fields
Michael Faraday discovered the existence of
electric generator
After discovering the relationship between electricity and magnetism, Michael Faraday created the first
electromagnetic radiation
James Clerk Maxwell discovered that __________ moves through space as a wave at the speed of light.
radio waves
James Clerk Maxwell discovered that visible light was only part of the electromagnetic spectrum and predicted the existence of
in motion
Everything in the universe is always
light
Albert Einstein discovered that nothing travels faster than __________ in a vacuum.
the passage of time
Albert Einstein discovered that, while the speed of light in a vacuum is a constant, ________ is a variable depending on location and velocity.
black hole
A ________ can form from the core of massive enough star that explodes (supernova) and then collapses in on itself.
black hole
The gravitation field created by a __________ is so strong, not even light can escape it.
event horizon
The spherical boundary around a black hole where gravity is strong enough to stop light from escaping is known as the
accretion disk
The disk of extremely heated matter revolving around and spiraling into many black holes is called a (an)
constant
Albert Einstein discovered that the speed of light in a vacuum is a __________.
is slower near strong gravitational fields
Albert Einstein discovered that the passage of time
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