Q&A Hero

Astronomy & Astrophysic

Q: As yet, no human probe has left our solar system and approached another star.
Q: Earth behaves as an artificial pulsar, with the strongest pulses for alien observers when North America is either rising or setting.
Q: Most radio telescope searches for signs of intelligent life are performed in the water hole.
Q: The water hole lies between 18 and 21 cm in wavelength in the radio spectrum.
Q: Due to the first strong commercial radio stations, our radio presence has now extended out to approximately 70 light years.
Q: The radio signals from Earth are greater than those from the Sun.
Q: Around Sun-like stars, we have, to date, only found Jupiter-like planets.
Q: The Milky Way Galaxy is forming about ten stars per month.
Q: Most bright blue stars we see with the naked eye are good candidates for life, since they have much larger habitable zones than does the Sun.
Q: An F-type star would have a larger habitable zone that does our Sun.
Q: Of the billions of possible combinations of atoms into organic molecules, only about 1500 actually occur.
Q: Earth-like planets have been observed outside our solar system orbiting in the habitable zone.
Q: The Drake Equation seeks to estimate the number of technological civilizations in the galaxy.
Q: Each factor in the Drake Equation has a well-known, established value.
Q: Binary star systems are considered good candidates in SETI.
Q: The one term of the Drake equation whose value remains completely unknown is the average lifetime of a technological civilization.
Q: We have found Titan's surface to have perfect living conditions for Earthlike life.
Q: The Murchison meteorite, a carbonaceous chondrite, contained many of the amino acids needed by living things on Earth.
Q: Interest in life on Mars has died since the latest surveys have found no signs of liquid water on its surface now.
Q: A Martian meteorite has revealed carbonate rocks and microfossils.
Q: NASA has found definite proof for the past existence of life on Mars.
Q: Of the terrestrial planets, Mars seems most promising to exobiologists.
Q: Europa is one of the most promising of the bodies in the outer solar system for life in its salty seas.
Q: Astronomical events, such as an asteroid impact or nearly supernova, have probably altered the course of evolution on Earth.
Q: The transition from single to multicellular life took over two billion years.
Q: Comets were likely a major agent in bringing both water and organic molecules to the surface of the early Earth.
Q: The Miller-Urey experiment relied on special conditions found only on Earth.
Q: Life emerged on Earth about a billion years after the solar system formed.
Q: The Miller-Urey experiment sought to recreate conditions in Earth's early atmosphere.
Q: The Miller-Urey experiment did produce amino acids and proteins.
Q: The definition of "life" requires only that an entity be able to reproduce itself.
Q: Organic molecules can only be made by living things.
Q: Living cells have already been recreated in our laboratories.
Q: From the beginnings of life on Earth, it took less than a billion years for single-celled organisms to evolve to multicellular organisms.
Q: If the inflation theory is correct, the geometry of the universe is flat and Euclidean.
Q: Deuterium abundance suggests that normal matter makes up only 3-4% of the critical density.
Q: Almost all the helium in the universe was formed between 2-15 minutes after the Big Bang.
Q: At decoupling, the protons and electrons formed transparent hydrogen atoms, allowing the radiation to escape and become the present microwave background.
Q: In the Big Bang, about 75% of the normal matter by mass was hydrogen atoms, and the other 25% almost entirely helium.
Q: The Big Bang has time in primordial nucleosynthesis to make only H and He in abundance.
Q: Primordial nucleosynthesis implies the Big Bang makes all elements up to iron.
Q: At decoupling, the electrons and protons were made from neutron decay.
Q: The majority of dark matter is normal protons and neutrons.
Q: Decoupling refers to the separation of matter and antimatter during inflation.
Q: During the epoch of decoupling, nuclei and electrons combined to form atoms.
Q: The 3 K background radiation is just the redshifted gamma wavelength radiation of the decoupling.
Q: The carbon in your DNA was fused in the first few minutes of the Big Bang.
Q: Of normal matter, about 25% of it by mass is still primordial helium even today.
Q: The background hiss that Bell Labs detected was the best observational evidence for the Big Bang.
Q: The radiation era lasted for only the first few billion years of the Big Bang.
Q: The cosmic microwave background is the total of all the radio emissions from all the galaxies and quasars in the universe.
Q: From the best current data, we infer the universe will expand forever.
Q: Perhaps as much as 95% of the matter in superclusters is dark matter.
Q: The fate or future of the universe depends only on the total number of galaxies and quasars.
Q: Like dark matter, dark energy will also retard the expansion of the universe.
Q: Einstein originally added a cosmological constant to his equations to prevent a presumably static universe from either contracting or expanding. Modern cosmologists have reintroduced it to their equations, where as the source of dark energy it causes the universe to expand ever faster.
Q: The latest observations of distant Type I supernovae suggest the universe is slowing down more than we had expected.
Q: The universe has been expanding at the same rate since its formation.
Q: Euclidean geometry is useful for most common problems, but the geometry of space requires general relativity as well.
Q: In a closed universe, if you could send out a powerful enough light, it would eventually return from behind you.
Q: The density of the universe is large enough that gravity alone will eventually halt its expansion.
Q: A gravitationally bound universe, with omega greater than 1.0, will expand forever.
Q: The critically bound universe, with omega = 1, is saddle shaped.
Q: In the Big Bang model, two possible fates exist: expansion forever, or cosmic collapse.
Q: If the value of H is doubled, it would also double the age of the universe.
Q: If the value of H has not changed since the Big Bang, then H = 70 km/s/Mpc will give a Hubble Time of about 14 billion years.
Q: The darkness of the night is due in part to the cosmological redshift, with the energy of the most distant objects diluted in the universal expansion.
Q: Olbers's paradox is solved in part by the fact that the universe is neither infinitely large nor infinitely old.
Q: The Big Bang was an expansion of matter into empty space.
Q: The cosmological redshift is not really a velocity at all, but a measure of the expansion of space-time.
Q: Hubble's law implies that, at some time in the past, all the matter in the universe was at one place.
Q: The cosmological redshift is a direct measure of the expansion of the universe, thus independent of direction.
Q: Galaxies are moving away from us and into the vast, empty space of the outer universe beyond the Big Bang.
Q: Olbers's paradox seeks the explanation for why the night sky is dark.
Q: The cosmological principle is the ultimate extension of the Copernican principle to the entire universe, in that there is no center at all.
Q: An infinite universe is a basic assumption of the cosmological principle.
Q: Describe the separation of the superforce and the effect it had on the universe.
Q: How does the cosmic background radiation relate to the Big Bang?
Q: Briefly describe the order of creation of normal matter in the Big Bang.
Q: Why was deuterium so critical in the primordial nucleosynthesis?
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