Unit 6
Where in space did the expansion of the universe begin?
everywhere at once
What is the strongest known force in the universe?
the strong nuclear force
For the complex biochemical reactions of life (as we know it) to happen, a solvent is required. What is that solvent for life on Earth?
water
According to our textbook, roughly what percent of the mass and energy contents of the universe is made up of dark matter plus dark energy?
95 percent
What relatively recent event shows that impacts continue to happen in our solar system even today?
a comet (which broke into more than 20 pieces) hit the planet Jupiter in 1994
At first, right after the Big Bang, the universe was too hot for nuclei and electrons to combine into the kinds of neutral atoms that are familiar to us today. How soon after the beginning did it become cool enough for neutral atoms to form?
a few hundred thousand years
Today, we believe that only a small number of elements were actually formed during the Big Bang. Which of the following was NOT one of these:
carbon
Scientists looking at an overview of physics today understand that there are four forces that govern all action in the universe. These four forces are the strong nuclear force, the weak nuclear force, electro-magnetism and
gravity
Any rock in the Earth's crust that has cooled from an originally molten state is called
igneous
Astronomers have discovered a planet orbiting Proxima Centauri, the star closest to the Sun. This is a star of spectral type M, with 12% the mass of the Sun and 15% the size of the Sun. The habitable zone around this star would be
much closer to the star than the Sun's
Regions where the continents or the sea floor are pulling apart are called
rift zones
The reciprocal of the Hubble constant (1/H) is a rough measure of the:
the age of the universe
After the Big Bang, in order for the universe to become transparent to light and other electro-magnetic radiation, what had to happen?
the density of the universe had to decrease (to 1000 nuclei per cubic centimeter or less)
Which of the following events in cosmic history is the most recent?
the formation of life on Earth
The model of the universe that involves an enormous increase of scale during a very short time in the early universe is called:
the inflationary universe model
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
The first satellite (spacecraft with instruments) to measure and confirm the cosmic microwave background was the:
COBE (COsmic Background Explorer)
The two scientists who first discovered the cosmic microwave background radiation were:
Gamow and Alpher
One way in which the ozone layer is useful for life forms on the Earth's surface is that it
absorbs ultra-violet light, preventing much of it from reaching the surface
If alien beings found one of the Voyager spacecraft in a million years, what would they find aboard?
an audio and video record
Which of the following statements about dark matter is FALSE:
astronomers have a pretty good idea what the dark matter is made of
How does a period of extremely fast inflation very early in the history of the universe explain the observation that the geometry of the universe looks flat (not curved) to us?
inflation increased the size of the universe so much that the resulting universe looks flat from any point of view
Which of the following points about our planet's atmosphere is FALSE?
its mass is a substantial part of the mass of the Earth
If we include the effects of deceleration in our calculations of the age of the universe, the age we get is:
less than the Hubble time
Based on many surveys of the average density of matter in the universe (regular matter and dark matter), astronomers now conclude that the average density of the universe is
less than the critical density
Which of the following did NOT happen during the first few minutes after the Big Bang?
some very massive early stars formed
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
According to the most recent data from satellites making precise measurements of the properties of the cosmic background radiation (CBR),
the dark energy makes up just a little less than 70% of the density of the universe, making it the most significant constituent of the mass-energy
Recent observations indicate that the universe is expanding faster today than it was a few billion years ago (that, in other words, the expansion of the universe is accelerating.) What kind of observations have led astronomers to this surprising conclusion?
the measurement of galaxy distances using Type Ia supernovae
A spot where magma rises to the surface can be seen as a
volcano
