ASTR Life in the Universe Midterm Exam 2
According to current astronomical data, roughly how old is the Universe
14 billion years
According to geological data, earth is how old?
4.5 billion years
order of events:
4.5 billion years ago: the earth formed 3.5 billion years ago: earliest known life on Earth 2 to 2.5 billion years ago: start of GOE 550 million years ago: the Cambrian explosion 2 million years ago: the first hominids evolve
Radio signal from aliens saying" we just received your message from 1939" how far away are they
40 lightyears away
what conditions do scientists suspect caused the sudden Cambrian explosion
All of the above: -organisms became sufficiently complex that more diversity became possible -oxygen reached critical levels necessary to support complex life -climate changes led to the end of snowball Earth
In Contact, what is the name of Hadden's adult theme park?
Babylon
the formation of the universe occurred with an event called the:
Big Bang
In Contact, what major character was killed by sabotage of the Machine?
Drumlin
What is the solution to the faint young sun problem
Earth's early atmosphere had more greenhouse gases than today's atmosphere
According to inorganic carbon cycle, if the amount of CO2 in the atmosphere gets too high
Earth's temp warms, which leads to more rainfall, which converts CO2 into limestone, reducing the amount of CO2 in the atmosphere
Contact characters:
Ellie Arroway- discovered the Message Xi Qiaomu- archaeology Devi Sukhavati- microbiology and astrobiology Vaygay Lunacharsky- russian physicist Abonnema Eda- discovered superunification, the Theory of Everything
the fact that Earth had liquid water and life 3 billion years ago even though the Sun back then had a lower energy output is known as the...
Faint Young Sun Problem
who was burned at the stake in 1600 for suggesting that there might be an infinite number of inhabited worlds in the universe
Giordano Bruno (Italian monk)
which of the following elements was created during Big Bang
Helium and Hydrogen
why can't Earth's water have been on the planet since it formed
High temps and constant bombardment by meteors and planetesimals on the early Earth would have driven any water away
the main chem building blocks of life are C, N, O, and Fe (iron) where are they created?
In nuclear reactions inside stars and exploding stars
which planet has a day/night cycle that lasts 24 hours and 37 min
Mars
contact characters
Palmer Joss- Christian preacher who converted after struck by lightning Ted Arroway- Ellie's father John Staughton- Ellie's step-father Ellie Arroway- radio astronomer and hear of Project Argus David Drumlin- Ellie's first graduate advisor and a highly-respected astronomer known for belittling his colleagues
first true life carried genetic info in...
RNA
Which planets could have methane ice?
Saturn, Uranus and Neptune
based on the cosmic calendar, roughly when did the Sun and the SS form
September 1st
which school of ancient greek thought dominated European science form the Macedonian Empire through the Middle Ages?
The Aristotelian
Ancient Greek school of thought who believe that heavens were made of the same substances than the Earth, so there could be many inhabited worlds in the heavens
The Atomists
In contact, which star is message from
Vega
what happened during Cambrian explosion?
a great variety of complex multicellular life arose
Krypton 85 has a half life of 11 years. Krypton planet explodes in 1945. In 1978, kryptonite to disable superman. How much of the original krypton 85 is left in the chunk of kryptonite
an eighth of it
last common ancestor of all life on earth was most likely closely related to ...
archaea living near deep sea thermal vents
Where did the Earth's present day water most likely come from
asteroids
The science of determining the conditions needed for life, searching for those conditions, and searching for life elsewhere is called
astrobiology
the first life on Earth is most likely to have originated
at deep sea ocean vents
humans and other great apes evolved from lesser primates. Most primates have tails, while great apes do not. According to Darwinian evolution, which of the following must be true
at some point in the past, the absence of a tail provided a slight survival or reproductive advantage for the ancestors of the great apes
origin of life
biogenesis
what info about origin of life came from Murchison meteorite
building blocks of life were common in the early solar system
Organisms that have evolved to survive under severe environmental conditions
extremophiles
True or False: evidence for nebular theory of planet formation is rarely around young stars
false
True or False: if Mars has any water ice left today, it is buried deep beneath the Martian surface and is not accessible
false
A .... is any evidence of past life
fossil
what is a piece of evidence that chloroplasts used to be independent cells incorporated into eukaryotic cells
have their own DNA different to the DNA in cell nucleus
wotf is true concerning humans and Darwinian evolution
humans and chimpanzees share a common ancestor
Geologists call the type of rock that form from cooling and solidification of magma:
igneous rock
first cell-like membranes on Earth were likely
lipids in water that self organized into spheres
Suppose a large asteroid were to hit Earth tomorrow, blasting bacterial rocks into space. If one of those rocks were to impact an icy moon and contaminate its pristine subsurface ocean with living organisms, we would call the process:
lithotranspermia
Curiosity mission has discovered that what planet was once warm enough to sport liquid water on its surface
mars
When two continental plates collide on the Earth's surface, what feature is most likely to form
mountain range
long neck giraffes develop because
natural selection
main mechanism of change in Darwinian evolution
natural selection
where would any life on europa and enceladus most likely be found
near underwater hydrothermal vents
what is one necessary but not sufficient condition to be called "life"
necessary for life to reproduce, but not sufficient as seen in a prion
How many species of humans exist on Earth today?
one
wotf is a leading hypothesis about how Earth got its organic molecules?
organics were brought to the Earth by comets and asteroids
potassium 40 radioactivity decays to argon 40 with a half life of 1.3 billion years, which is parent/daughter
potassium is parent isotope and argon is the daughter isotope
In Contact, what was the first clue that the Message was from an intelligent civilization and not from a natural source of radio waves?
prime numbers, they do not occur naturally in nature
When an unstable element decays spontaneously into another element, we call it
radioactivity
geologists determine the structure of earth's interior by using
seismic wave data
natural selection in humans today
sickle cell amenia
why don't scientists believe silicon based life could exist
silicon bonds are weaker than carbon bonds, so complex molecules are fragile
the abiotic (non-biological) carbon cycle:
stabilizes Earth's temperatures over long periods of time
oldest known fossil on life on Earth
stromatolites
what type of planets formed from dust that had lost its gooey, icy outer coating, when SS was created
terrestrial planets
...so why aren't prions considered to be living organisms
they don't have genes, so they cannot undergo Darwinian evolution
what has happened to most of the CO2 outgassed by volcanoes over Earth's history
transformed into limestone and other carbonate rocks