Astrology final

The size of the universe is not known, but it has been expanding and accelerating that expansion for 13.8 billion years. Our "cosmic horizon" is determined by that time and the speed of light. We cannot see farther than 13.8 billion light-years in any direction. However, within this observable region there are at least _______ galaxies. A) 100 billion B) 100 million C) 10 million D) 10 billion

A) 100 billion

We can measure the amount of light received by a telescope on Earth, but in order to know the total power (luminosity) emitted by a star we must find its distance. Distances to the nearest stars are obtained using trigonometry and a method called parallax. Parallax is the apparent motion of a nearby star relative to much more distant stars due entirely to Earth's orbital motion around the Sun. The effect is small, less than 1800 times smaller than the diameter of the Moon. If the parallax angle (p) is 1 second of arc then the distance (d) to the object = 1 parsec by definition, where the parsec is equal to 206,265 Astronomical Units. This is also equal to 3.26 light-years. If the measured parallax angle for a star is 0.01 seconds of arc (arcsec), how far away is the star? [Remember that d(parsec) = 1/p(arcsec) ; modern facilities can measure parallax angles 40,000 times smaller than 1 arcsec.] A) 326 light-years B) 32.6 light-years C) 1 light-year D) 3.26 light-years

A) 326 light-years

What should we consider rare? Perhaps one in a million? If so,then the statistics of of stars and planets in our galaxy matter. The Kepler mission estimated that there are about 40 billion Earth-similar planets in our Galaxy. If only one in a million is actually a true Earth analog, how many is that? A) 40,000 B) 40 million C) 400 million D) 40

A) 40,000

Our current top speed for space probes is about 30 km/s (67,000 mph). This is 10,000 times slower than the speed of light. How long would it take to reach Proxima Centauri (4.2 ly) at this speed? A) 42,000 years B) 420 years C) 4,200 years D) 42 years

A) 42,000 years

How is intelligence defined in the Drake Equation? A) A civilization willing and able to communicate over interstellar distances B) A civilization that has developed language C) A civilization that communicates using telepathy D) A civilization capable of spaceflight

A) A civilization willing and able to communicate over interstellar distances

Which of the following is not a Galactic Danger Zone? A) Being in a sparse populated, low-density, part of the galaxy where the stars and gas are co-rotating. B) Being too close to a region where massive stars are forming, because these stars will go supernova in just a few million years. C) Being too close to the massive black hole at the center of the Milky Way. D) Being too close to the neutron star remnant of an earlier supernova, because these objects radiate beams of intense high-energy radiation.

A) Being in a sparse populated, low-density, part of the galaxy where the stars and gas are co-rotating.

If the Sun was somehow replaced with a Black Hole of the same mass, its Event Horizon would be 3 km in radius; compare this to the Sun's actual radius of 700,000 km. Ignoring the impact on living organisms due to the sudden disappearance of sunlight, what would happen to the orbit of planet Earth? A) Earth's orbit would not change B) Earth would spiral outwards and merge with Jupiter. C) Earth would suddenly shoot off in a straight line as predicted by Newton's First Law. D) Earth would spiral inwards towards the Black Hole.

A) Earth's orbit would not change

Gliese 667Cc is a planet on the list of possible habitable worlds. The small letter "c" indicates that it was the second planet discovered in this system; the first planet discovered is always designated with a b. What then does the capital letter "C" signify? A) Gliese 667 is a triple system and the planet in question orbits the third (C) component. B) The letter "C" refers to the Catalog in which this star is recorded. C) The letter "C" is an indication that the planet is very large (colossal). D) Gliese 667 is a double system and the planet in question orbits the second component.

A) Gliese 667 is a triple system and the planet in question orbits the third (C) component.

How do we account for "hot Jupiters" like Dimidium in the 51 Pegasi system? A) Planet migration caused by gravitational encounters during the formation of the planetary system. B) Planetary migration caused by an advanced species that can move planets around. C) The large Jupiter-like planet simply formed close to the star, even though that location is far inside the Frost Line. D) An unexplained accident of nature.

A) Planet migration caused by gravitational encounters during the formation of the planetary system.

SETI provides a possible way to resolve the Fermi Paradox. If we cannot find any evidence of a technologically advanced civilization then we can conclude that three of the following four statements are possible, but one is NOT. Which one is logically wrong? A) Technologically advanced species are common. B) Technologically advanced species may exist, but they are keeping their existence hidden from us. C) Technologically advanced species may be common, but interstellar travel and communication is not (thus signals will be very rare). D) There are no other technologically advanced species.

A) Technologically advanced species are common.

The Doppler Effect is the change in pitch (frequency) of a sound wave caused by the motion of the emitting object, e.g. the siren of a rapidly moving emergency vehicle towards or away from the observer. Light waves emitted by a moving source do the same. The Doppler Effect in light allows astronomers to measure the motion of stars. If I record the spectrum of a distant star like the Sun, and I see that all of the dark absorption lines in the spectrum are shifted to the red by a small amount relative to those in the Sun's spectrum, what does this mean? A) The star has a component of its motion away from Earth. B) The star has a component of its motion toward Earth. C) The star is unusual and likely to explode. D) There is an error in the measurement because a shift to the red is impossible.

A) The star has a component of its motion away from Earth.

When one star orbits another, we can witness the back and forth motion of spectral lines in the stellar spectrum, even if our telescopes lack the angular resolution to separate the two stars on the sky. This Doppler shift yields the star's orbital ______, and the time interval associated with the repetitive motion of the lines back and forth is in fact the orbital ______. From both of these numbers we can deduce the orbital radius, and through Newton's form of Kepler's Third Law we can find the total _____ of the binary system. A) Velocity; Period; Mass B) Period; Velocity; Size C) Distance; Period; Mass D) Distance; Velocity; Size

A) Velocity; Period; Mass

We hope to detect the "spectral fingerprints" of biological life by studying the atmospheres of exoplanets. To understand what we might find it is instructive to look at the spectrum of the Solar System's planets as seen from space. Earth's infrared spectrum has two features that are not seen in the spectrum of Venus or Mars. These are broad absorption features due to _______ and ______. A) methane and ozone B) oxygen and nitrogen C) carbon dioxide and water vapor D) methane and carbon dioxide

A) methane and ozone

Nearly all dense objects emit thermal electromagnetic radiation, unless they are at Absolute Zero (0 K = -273 C)! This radiation is called thermal because the emitted photon energies match the thermal kinetic energy of the molecules in the object. Remarkably, the full spectrum (energy versus wavelength) of thermal radiation from any object depends on only one parameter, its __________. A) temperature B) Remarkably, the chemical composition of the object does not matter. C) chemical composition D) electrical conductivity mass density

A) temperature

The Radial Velocity Curve of a star with an orbiting exoplanet is a plot of the radial component of the star's Velocity versus Time. Velocity is obtained from the Doppler Effect. The amplitude of the curve is related to ___________, the asymmetry of the curve tells us how _______ the orbit is, and the interval of time over which the velocity changes occur is the __________. A) the planet's mass; elliptical; orbital period of revolution B) the orbital shape; large; orbital period C) the planet's radius; large; rotation period of the planet D) the planet's mass;elliptical; rotation period of the planet on its axis

A) the planet's mass; elliptical; orbital period of revolution

The "rocket equation" relates the final velocity of a chemical rocket to A) the velocity of its exhaust gases, and the ratio of the mass of the rocket with all its fuel, to the mass of the rocket after its fuel is consumed B) the Earth's escape velocity and the payload-to-fuel mass ratio C) the mass of its payload and the escape velocity of Earth D) The velocity of its exhaust gases and mass of the rocket before launch

A) the velocity of its exhaust gases, and the ratio of the mass of the rocket with all its fuel, to the mass of the rocket after its fuel is consumed

The phenomenon that we refer to as color, is the ability of our eyes to distinguish between light waves of different _______. A) wavelengths B) intensities C) speeds D) polarization

A) wavelengths

Bert and Ernie are two friends of the same age. Traveling very close to the speed of light (e.g. 0.999c), Bert visits the star Vega (~25 light-years away) while Ernie remains on Earth. When Bert returns to Earth he will be A) younger than Ernie. B) older than Ernie. C) surprised to find that Ernie has not been born. D) the same age as Ernie.

A) younger than Ernie.

When light interacts with matter, it behaves as if the energy is concentrated rather than spread out in a wave. Energy bundles of light - quanta - are also called photons. Photons may be emitted, absorbed, transmitted or reflected/scattered by atoms. Which of these interactions cause us to attribute the color of red to a certain type of rose? A) All other wavelengths (colors) are reflected and only red is emitted. B) All other wavelengths (colors) are absorbed and only red is reflected/scattered. C) All other wavelengths (colors) are transmitted and only red is emitted. D) All other wavelengths (colors) are scattered and only red is absorbed.

B) All other wavelengths (colors) are absorbed and only red is reflected/scattered.

If you were asked to write down three factual sentences that describe what makes interstellar space travel so very difficult, which three phrases would you select from the five below? A. Interstellar space travel will always be too expensive B. Interstellar space travel requires technology we will never ever have C. The enormous distances between stars is a fundamental problem D. The fastest speed possible is the speed of light E. Enormous amounts of energy are required to accelerate any craft to high speed A) A, C, and E B) C, D, and E C) A, B, and E D) B, C, and D

B) C, D, and E

Intelligence on Earth seems to be an advantageous trait. Sharks and dolphins, one a fish the other a mammal, are quite distinct intelligent life forms that nevertheless have remarkably similar body plans, which evolutionary pressure has carved out over time. This, and other examples such as the widespread development of eyesight, and increasing brain size over time, are indicative of A) Artificial Evolution B) Convergent Evolution C) Insurgent Evolution D) Divergent Evolution

B) Convergent Evolution

Really small planets were difficult for the Kepler Space Telescope instruments to find. So, in order to estimate the frequency of Earth-size exoplanets, we must correct for this sampling bias. When this is done however, we find that A) Earth-size planets may actually be as common as "hot Jupiters." B) Earth-size planets may actually be the most common type of exoplanets. C) the results are inconclusive concerning the frequency of Earth-size exoplanets. D) Earth-size planets may actually be the most rare type of exoplanets.

B) Earth-size planets may actually be the most common type of exoplanets.

Another statement by Rare Earth proponents is that Earth has a good balance of oceans and continents. Without any land surfaces, advanced intelligent life like us could not develop. While it is not at all clear why a balance of land and water would be rare, what other points can be made in opposition to this statement? A) We don't know how these factors impact evolution, so it is safer to simply assume that Earth is rare.. B) From decades of research, it looks like Mars also had a balance of water and land in the past, and possibly Venus too. Temperature extremes are challenging, but extremophiles show that life "adapts." We lack evidence to say how these factors impact evolution. C) From decades of research, it looks like neither Mars nor Venus ever had a balance of water and land surface in the past. Even if life "adapts," the lack of evidence is proof that Earth is rare. D) From decades of research, it looks like Mars also had a balance of water and land in the past, and possibly Venus too. Temperature extremes are challenging, but extremophiles show that life "adapts." Since we lack evidence to say how these factors impact evolution, we conclude that Earth is rare..

B) From decades of research, it looks like Mars also had a balance of water and land in the past, and possibly Venus too. Temperature extremes are challenging, but extremophiles show that life "adapts." We lack evidence to say how these factors impact evolution.

We can trace the origin of the universe from the Big Bang to the formation of rocky planets and life. A key step in that process is the ___________ cycle in which the interstellar medium where future stars and planets will form is _________________ due to thermonuclear reactions in stars and supernovae explosions. A) Carbon Dioxide (CO2); depleted with heavy elements B) Gas-Star-Gas; enriched with heavy elements C) Gravitational clustering; compressed and heated D) Gas-Star-Gas; depleted in heavy elements E) Carbon Dioxide (CO2); enriched with heavy elements

B) Gas-Star-Gas; enriched with heavy elements

Based on reasonable guesses for the numbers in the Drake Equation, there is a non-zero probability that alien life with the ability to contact us should exist in our Galaxy. This led physicist Enrico Fermi to ask "Where are they?" One explanation of the "Fermi Paradox" is the ___________ Theory, the basic idea of which is that there is a barrier to advancement and longevity that few civilizations can pass. A) Natural Selection B) Great Filter C) Narrow Filter D) Von Neumann

B) Great Filter

Astronomers began recording the spectra of stars on photographic plates in the late 1800s. Letters of the alphabet were used to group together stars that had the same or very similar spectra based on visual appearance of the spectrum. Later, the letters had to be re-arranged when it was learned how to recognize a temperature sequence in the spectra. The Sun is designated a G type star with a surface (photosphere) temperature of 5,800 K. The coolest stars have numerous absorption lines in their spectra and are of type ____, corresponding to temperatures around _____. By contrast, the hottest stars of type ____ have temperatures around ______. A) M; 5,800 K; B; 50,000 K B) M; 3,000 K; O; 50,000 K C) K; 3,000 K; B; 50,000 K D) K; 5,800 K; O; 50,000 K

B) M; 3,000 K; O; 50,000 K

Five spacecraft are leaving the solar system at the present time. Which is not one of them? A) New Horizons B) Perseverance C) Voyager 1 D) Voyager 2 E) Pioneer 1

B) Perseverance

The Earth Similarity Index (ESI) is a mathematical formula that weights the product of four terms to estimate how much an exoplanet resembles Earth in physical characteristics. The four terms are radius, density, escape velocity (gravity), and surface temperature. Which of the four ESI parameters is the dominant factor, i.e. given the greatest weight? A) Escape Velocity B) Surface temperature C) Density D) Radius

B) Surface temperature

In the late 19th century, Scottish physicist James Clerk Maxwell predicted the existence of waves of electricity and magnetism that could travel through the vacuum of space at the known speed of light, 300,000 km/s. Such electromagnetic waves can have many different wavelengths and frequencies, but A) The sum of wavelength and frequency must equal the speed of light. B) The product of wavelength and frequency must equal the speed of light. C) The ratio of wavelength and frequency must equal the speed of light. D) Wavelength must be less than frequency, independent of the speed of light.

B) The product of wavelength and frequency must equal the speed of light.

Two of the factors that Rare Earth proponents site are the following: the Sun is a stable star that is also the right distance from the Galactic Center. Which response below counteracts these statements? A) We have no evidence to tell us anything about whether or not the stability of a star is a factor in supporting life. B) There a great many stable stars and G, K amd M stars make up 97% of the total. Moreover, there is a great swath of distances from the center of the galaxy that are just as good as ours. C) All stars are stable enough for life, and distance from the center of the galaxy has no effect. D) Most stars in the galaxy are like the Sun, and since the galaxy is huge, distance from the center hardly matters.

B) There a great many stable stars and G, K amd M stars make up 97% of the total. Moreover, there is a great swath of distances from the center of the galaxy that are just as good as ours.

Which of these statements about the rarity of a planet like Earth with advanced life forms (including us), follows proper reasoning based on the Scientific Method of confronting ideas with experiments and observations? A) Given the principle of mediocrity (like the Copernican principle), it is probable that the universe teems with complex life. B) We simply do not have enough data to say that Earth is rare or not, because, while we have discovered exoplanets, we have yet to discover life elsewhere. C) By modern observations, Earth appears to be only one of a large number of rocky planets discovered to be orbiting other stars. D) The evolution of multicellular organisms and, subsequently, intelligence requires an improbable combination of astrophysical and geological circumstances.

B) We simply do not have enough data to say that Earth is rare or not, because, while we have discovered exoplanets, we have yet to discover life elsewhere.

No one would doubt that the ancient Greeks were intelligent, but it would be impossible to assess the presence of that level of intelligent life from another star system without sending probes here. However, once intelligent life reaches the level of space travel then it might be possible to detect such a civilization from afar. Therefore, the search for extraterrestrial intelligence (SETI) is specifically a search for signs of A) pyramids B) advanced technology C) agriculture D) great works of art

B) advanced technology

In our quest to understand the possibilities for Life in the Universe, we must look beyond the Solar System to other stars. But how do we discover what is going on in other star systems? We need a messenger of information. That messenger is light. But what is light? Light is a form of energy. It is called radiative energy, and it is one of the three major categories of energy. The other two categories are A) mass and thermal. B) kinetic and potential. C) nuclear and gravitational. D) chemical and electrical.

B) kinetic and potential.

The Rare Earth proposal posits that all extremophiles beyond Earth will be microbial life forms, but based on life on Earth this seems unlikely to be true. There exist a number of small but complex animal life forms that can survive in extremely harsh conditions. For example, a __________ can survive in the vacuum of space. A) worm B) tardigrade C) nematode D) crustacean

B) tardigrade

Thermal (heat) energy is a measure of the total kinetic energy of a system of particles. Thermal energy is measured in joules, the same as any other kind of energy. However, the average kinetic energy of a system of particles is measured by its _________ on an absolute scale. A) acceleration B) temperature C) pressure D) heat

B) temperature

Radio waves are probably the most efficient way to communicate with extra-terrestrial civilizations because ] A) the interstellar medium is essentially opaque to radio waves, because they travel at the speed of light. B) the interstellar medium is essentially transparent to radio waves, which travel at the speed of light. C) Radio waves travel faster than the speed of light. D) Radio waves are the most penetrating of all electromagnetic waves, more so than gamma rays and X-rays.

B) the interstellar medium is essentially transparent to radio waves, which travel at the speed of light.

The observed slowing down of time predicted by Einstein's Special Theory of Relativity for an object traveling close to the speed of light (670 million miles per hour) is referred to as A) time expansion. B) time dilation. C) a time warp. D) time after time.

B) time dilation.

Based on the Kepler mission statistics, there could be ~40 billion Earth-sized planets within the habitable zones of their stars in the Milky Way alone. However, some parts of the Galaxy may be less hospitable to life on these planets than other locations. Let's assume then that there are only 1 billion planets in our galaxy where life could exist. Since there are about 100 billion other galaxies in the observable universe, how many habitable worlds does this imply? Write your answer using Scientific Notation. A) 1.0 E 9 B) 1.0 E 18 C) 1.0 E 20 D) 1.0 E 11

C) 1.0 E 20

The power (energy per second or luminosity) emitted from each square meter of a star's surface is proportional to the fourth power of the star's absolute temperature (T); this is the Stefan-Boltzmann law (σT4). We know that the temperature of the Sun is 5,800 K. Compared to the Sun, a star with twice the Sun's temperature would emit _______ as much power per square meter. A) 2 times B) 8 times C) 16 times D) 4 times

C) 16 times

What kind of message from Earth is being carried by the Pioneer space probes launched by NASA in the 1970s, and now leaving the Solar System? A) A gold-coated copper record with a digital star map of the galaxy that includes the location of the Sun relative to nearby pulsars. B) An engraved plaque showing a male and a female human, and the location of the Solar System relative to nearby stars with exoplanets. C) An engraved plaque showing a male and a female human, and the location of the Solar System relative to nearby pulsars (spinning neutron stars). D) A gold-coated copper record with directions to Earth, and a message of peace from humanity.

C) An engraved plaque showing a male and a female human, and the location of the Solar System relative to nearby pulsars (spinning neutron stars).

Why does the Doppler shift method of detecting extrasolar planets only give us the minimum mass of the orbiting planet? A) Because we usually don't know the diameter of the planet. B) Because we usually don't know the mass of the parent star all that well. C) Because we usually don't know the inclination of the orbital plane. D) Because we usually don't know the density of the planet.

C) Because we usually don't know the inclination of the orbital plane.

The so-called Rare Earth Hypothesis, is best described by which of the following statements? A) Since there are no other known Earth-mass planets in our Galaxy, Earth must be rare and therefore complex life must be rare. B) Complex extraterrestrial life of the kind found on Earth is a very probable phenomenon that required no fortuitous circumstances, and is thus likely to be extremely common. C) Complex extraterrestrial life of the kind found on Earth is a very improbable phenomenon that required many fortuitous circumstances, and thus likely to be extremely rare. D) Complex extraterrestrial life of the kind found on Earth is so rare that no attempts to find it are worthwhile.

C) Complex extraterrestrial life of the kind found on Earth is a very improbable phenomenon that required many fortuitous circumstances, and thus likely to be extremely rare.

When a planetary transit occurs, the amount of light lost is proportional to the area of the star covered up. Since we know the radius of the star itself, and we can measure the brightness change, we can deduce the planet's radius. If we also have the mass of the planet from the Doppler method, what fundamental planetary property can then be deduced? A) Diurnal rotation (length of day) B) Axial tilt C) Density D) Albedo (reflectivity) E) Age

C) Density

The Rare Earth proposal is based on the idea that a lot of things "had to be right" for advanced life to develop on Earth. It is not impossible for this to happen - we are here after all - but it might be a rare phenomenon in the galaxy. We don't have enough data to say for sure. However, which of the following is NOT one of the things that had to be "just right" according to the Rare Earth concept? A) Our Sun is a normal star at the right distance from the galactic center. B) Earth has a large moon which causes significant tides. C) Earth is the third planet from the Sun, which is critically important for the development of life. D) Earth is a rocky planet with the right ocean-continent balance.

C) Earth is the third planet from the Sun, which is critically important for the development of life.

From our whirlwind study of the properties of stars this week we can infer some "stellar requirements for life in the universe." Although there are over 200 billion stars in our galaxy alone, not all those stars are as welcoming to life as our Sun. A star must last long enough for life to emerge and evolve, and we also need a relatively stable habitable zone that changes only slowly with time. We hope that stars with such properties are also plentiful rather than rare! From what you have learned, which of the following statements is correct? A) G, K, and M class stars represent 3% of all stars, but their long lives allow enough time to evolve life. B) G, K, and M class stars represent 3% of all stars, and their short lives allow enough time to evolve life. C) G, K, and M class stars represent 97% of all stars, and their long lives allow enough time to evolve life. D) G, K, and M class stars represent 97% of all stars, but their short lives don't allow enough time to evolve life.

C) G, K, and M class stars represent 97% of all stars, and their long lives allow enough time to evolve life.

Visible light is only a very, very small part of an enormous spectrum of radiant electromagnetic energy that spans a range of wavelengths from smaller than the nucleus of an atom to larger than a hundred football fields. From the shortest to the longest wavelengths, this spectrum is usually divided into the following regions A) Visible, UV, X-rays, Gamma rays, IR, microwaves, and radio. B) X-rays, UV, visible, IR, microwaves, radio and gamma rays. C) Gamma rays, X-rays, UV, visible, IR, microwaves, and radio. D) Radio, microwaves, IR, visible, UV, X-rays, Gamma rays.

C) Gamma rays, X-rays, UV, visible, IR, microwaves, and radio.

In 1995 astronomers made two major discoveries. The first sub-stellar mass object, or failed star - also called a brown dwarf - was discovered thanks to advances in infrared technology. (These objects are the missing link between the smallest stars and gas-giant planets like Jupiter.) In the same year the first true exoplanet, a planet orbiting another Sun-like star, was also found. The planet was initially called 51 Pegasi b, but has now been officially named Dimidium. (The star 51 Pegasi is 50 light-years away.) What was surprising about this first exoplanet? A) It was an Earth-sized planet in an orbit similar to our own. B) It was a tiny Pluto-sized planet closer to its star than Mercury is to the Sun. C) It was a Jupiter-sized planet closer to its star than Mercury is to the Sun. D) It was a huge planet, 10 times the size of Jupiter, in a one-year orbit around the star.

C) It was a Jupiter-sized planet closer to its star than Mercury is to the Sun.

What was unusual about the discovery in 2017 by the Spitzer Infrared Space Telescope of planets in the star system called Trappist-1, which is located about 40 light-years from Earth in the constellation Aquarius? A) It was the first time that planets were found to orbit a small red dwarf star. B) It was the first time that multiple planets were found around a single star. C) It was the first known system of seven Earth-size planets around a single star, three of which are in the star's habitable zone. D) It was the first known system of seven Jupiter-size planets around a single star, two of which are in the habitable zone where their moons could sustain liquid water.

C) It was the first known system of seven Earth-size planets around a single star, three of which are in the star's habitable zone.

The famous Drake Equation is not a law of physics. It is often described as a way to organize our ignorance. The goal is to write down all the factors that we would need to know in order to predict the number (N) of advanced alien civilizations in our own Milky Way galaxy. The original equation looks like this N = Nstars fpneflfifcL/Lg We are only confident about four of these factors. Select the correct four from the list below. A) fraction of planets with life; fraction of planets with intelligent life; fraction of civilizations with a detectable signal; lifetime of an advanced civilization B) Number of stars in the Milky Way; fraction of stars with planets; number of potentially habitable planets; fraction of planets with life. C) Number of stars in the Milky Way; fraction of stars with planets; number of potentially habitable planets; lifetime of the galaxy. D) Number of potentially habitable planets; fraction of planets with life; lifetime of an advanced civilization; lifetime of the galaxy.

C) Number of stars in the Milky Way; fraction of stars with planets; number of potentially habitable planets; lifetime of the galaxy.

For a planet to receive as much radiant energy as Earth from a M-type star having one-ninth (1/9) the Sun's luminosity, the planet would have to orbit its star at A) One-fourth Earth's distance from the Sun (0.25 AU). B) The same distance as Earth (1 AU). C) One-third Earth's distance from the Sun (0.33 AU). D) One-ninth Earth's distance from the Sun (0.11 AU).

C) One-third Earth's distance from the Sun (0.33 AU).

If electromagnetic radiation is produced by any thermal source with a non-zero absolute temperature (T), then why don't people glow in the dark? A) We are much too small to emit enough visible light for us to see it. B) People don't contain enough radioactive material to emit visible light. C) People do glow, but at infrared wavelengths that our eyes cannot see; we are not hot enough to emit visible light. D) This law only applies to things, not people.

C) People do glow, but at infrared wavelengths that our eyes cannot see; we are not hot enough to emit visible light.

Overall, what do current observations suggest about planet types in other planetary systems? A) Planets that fall into either the terrestrial or jovian categories are extremely rare outside of our own solar system. B) Jovian planets are common, whereas terrestrial planets are rare. C) Planets come in a wider range of types than the planets in our own solar system. D) All planets fall into the same terrestrial and jovian categories as the planets in our solar system.

C) Planets come in a wider range of types than the planets in our own solar system.

We can determine at least eight physical parameters of an exoplanet system using the Transit and Radial Velocity methods, but none of these give us a "signature" for life. In order to look for signatures of life we need _______, most likely from a space telescope like JWST. A) biometrics B) Interferometry C) Spectroscopy D)Imaging

C) Spectroscopy

The Kepler mission revealed a remarkable discovery about the make-up of exoplanet systems compared to our own solar system. What was this new and unexpected result? A) The most common type of planet is a "hot" Jupiter orbiting very close to the parent star. B) Earth sized planets and Neptune sized planets, which exist in our solar system, are more common than Super-Earth and mini-Neptune sized planets. C) Super-Earth sized planets and mini-Neptune sized planets, neither of which exist in our solar system, are more common than planets of the size of Earth or Neptune. D) All planet types are equally common.

C) Super-Earth sized planets and mini-Neptune sized planets, neither of which exist in our solar system, are more common than planets of the size of Earth or Neptune.

The Hertzsprung-Russell diagram is a useful way to collect all the physical information we can glean about stars into one single plot. Luminosity (relative to the Sun) is plotted on the y-axis, and the star's temperature is shown on the x-axis. It is found that the vast majority of stars lie along a diagonal line called ____________. It is also found that a star's _____ increases from the lower right to the upper left along this line. A) The Red Giant Branch; Mass B) The White Dwarf Branch; Radius C) The Main Sequence; Mass D) The Main Sequence; Radius

C) The Main Sequence; Mass

The Andromeda Galaxy (M31) is 2.5 million light-years from the Milky Way. Which of the following statements is true? A) The distance to M31 is 25 times the diameter of the Milky Way, indicating that M31 is incredibly far away compared to the size of the Milky Way. B) The distance to M31 is only 25 times the diameter of the Milky Way, indicating that galaxies cluster much farther apart than stars within those galaxies. C) The distance to M31 is only 25 times the diameter of the Milky Way, indicating that galaxies cluster closer to each other than do stars within those galaxies. D) The fact that the distance to M31 is only 25 times the diameter of the Milky Way tells us nothing about the clustering of galaxies relative to the clustering of stars within those galaxies.

C) The distance to M31 is only 25 times the diameter of the Milky Way, indicating that galaxies cluster closer to each other than do stars within those galaxies.

A major claim in the Rare Earth Hypothesis is the existence Earth's large moon due to a chance collision during planet formation. It is claimed that the Moon was essential to life because it controls the tides. This concern stems from a statement made by Darwin that life might have started in a "tidal pond." How is this claim refuted? A) Today we know that all exoplanets have large moons. B) Today, we know that moons have nothing to do with the formation of life on a planet. C) Today, we think it is more likey that life began in the oceans, with deep volcanic vents playing a critical role, rather than shallow tidal ponds. D) Today we know that a planet with life will attract a large moon.

C) Today, we think it is more likey that life began in the oceans, with deep volcanic vents playing a critical role, rather than shallow tidal ponds.

Why is it very challenging to study the atmospheres of almost all the exoplanets discovered so far? A) The light from the planet cannot be separated from the light from the star. B) There is no light from the planet's atmosphere so we can't study it. C) We must find a way to subtract out the enormously brighter light from the star. D) We must find a way to subtract out the enormously brighter light from the planet.

C) We must find a way to subtract out the enormously brighter light from the star.

Including the very faintest red dwarf stars, there is probably about 400 billion stars in the Milky Way galaxy. The Sun is classified by its spectrum as a G-type star with a surface (photosphere) temperature of 5,800 K (just over 6,000 C). Such stars are A) very common, making up 50% of the total. B) quite rare, making up less than 0.7% of the total. C) fairly common, making up 7% of the total. D) the most common, making up 75% of the total.

C) fairly common, making up 7% of the total.

There are about 400 billion stars in the Milky Way galaxy. The Sun is classified by its spectrum as a G-type star with a surface (photosphere) temperature of 5,800 K (just over 6,000 C). Such stars are A) very common, making up 50% of the total. B) fairly rare, making up less than 0.7% of the total. C) fairly common, making up 7% of the total. D) the most common, making up 75% of the total.

C) fairly common, making up 7% of the total.

Of the 413 known stars in a volume around the Sun with a radius of 32.6 light-years (10 parsecs) we have so far discovered that ~64 (15.5%) have planetary systems. One of these exoplanets is Ross 128b, an Earth-sized world orbiting in the habitable zone of its red dwarf star. What is particularly interesting about this system is that the red dwarf star is considered a "quiet" star, which means A) it is colder than a normal red dwarf star. B) it is not loud and produces no noise. C) it is not active and prone to flares D) it is warmer than a normal red dwarf star

C) it is not active and prone to flares

Over 5,000 exoplanets have been confirmed so far. However, when we look carefully at a plot of exoplanet size (radius relative to Earth) versus the planet's orbital period around its star in days, we see that A) no planets have been found with orbital periods similar to Earth's. B)the rocky planets discovered so far have orbital periods much greater than 365 days. C) the rocky planets discovered so far have orbital periods much less than 365 days. D) no Earth-sized planets have been found.

C) the rocky planets discovered so far have orbital periods much less than 365 days.

Some telescopes use lenses, but most large professional telescopes use giant curved reflecting mirrors to collect and focus the light of distant objects. Larger telescopes are important because A) they are cheaper and easier to build. B) they enable more astronomers to use them. C) they collect more light energy in proportion to the area of the telescope, and the angular resolution improves with a larger diameter. D) they collect more light energy in proportion to the diameter of the telescope, and the angular resolution improves with a larger area.

C) they collect more light energy in proportion to the area of the telescope, and the angular resolution improves with a larger diameter.

From 2009-2018 NASA's Kepler spacecraft observed over 100,000 stars and discovered thousands of exoplanets. Fill in the blanks in this statement. Kepler observes ______, which yields the ______ of the exoplanet, and therefore the _______, provided we also know the mass from Doppler velocity measurements. A) eclipses; density; radius B) transits; density; radius C) transits; radius; density D) eclipses; radius; density

C) transits; radius; density

It is reasonable to ask if there is something special about the Sun's location within our galaxy, the Milky Way. The Milky Way is a huge yet highly flattened aggregation of stars that orbit a common center. Seen edge-on from the outside, the Milky Way is 100,000 light-years in diameter, but only ______ light-years thick. The Sun is located ______ light-years from the Galactic Center. A) 10,000; 26,000 B) 10,000; 50,000 C) 1,000; 50,000 D) 1,000; 26,000

D) 1,000; 26,000

If an advanced civilization wanted to beam a powerful radio signal in our direction, what frequency (wavelength) would they likely choose? (Remember, the number of available frequencies on the "radio dial" is almost infinite, so we need to know what frequency to tune our radio telescopes to.) A) 1070 kHz (21 cm) B) 5.38 MHz (3 cm) C) 21 MHz (1420 cm) D) 1420 MHz (21 cm)

D) 1420 MHz (21 cm)

Consider the history of life on Earth. Cyanobacteria started releasing oxygen into the atmosphere ______ billion years ago, but the build up was slow. The Cambrian explosion of diverse phyla began _____ million years ago, but the earliest ________ date back only a few million years. A) 4.4; 65; homo sapiens B) 3.5; 540; dinosaurs C) 4.4; 225; mammals D) 3.5; 540; hominids

D) 3.5; 540; hominids

Suppose the number of Earth-like potentially habitable worlds in the galactic habitable zone is 6 billion. Assume that all of these planets have life (flife =1), but only one in a million get an advanced civilization. By dividing 6 billion by one million we find that this means that only 6,000 civilizations ever arise. If a civilization lasts 1 billion years, compared to the 10 billion years that the galaxy has existed, then only 1 in 10 civilizations exist now. In this example, how many advanced civilizations exist now? A) 60,000 B) 60 C) 6,000 D) 600

D) 600

When the energy at each wavelength is spread out and recorded, we obtain the spectrum of the light. When examined very closely, the spectrum of the Sun has numerous dark lines against a continuous (rainbow) background of colors. What kind of spectrum is this? [Recall that the dark lines, which are simply images of the narrow rectangular entrance slit of the spectrometer, represent wavelengths where energy is missing. Check the lecture notes!] A) Combination of all three B) Continuous C) Emission D) Absorption

D) Absorption

According to Rare Earth proponents, our planet is very special in terms of advanced life forms because Earth is the only planet currently in the Sun's habitable zone, and it's just barely in there. The "greenhouse effect" on Earth is key, but it has to be "just right." Because of this special arrangement they say, life elsewhere will be rare. If we truly wish to apply the Scientific Method, how should other scientists react to this statement? A) We don't know that Earth's greenhouse effect is a major factor for advanced life. Therefore, even with just one example, it is possible to prove Cause and Effect, even if there is no experimental test.. B) Earth, with its advanced life, is rare. To prove Cause and Effect you don't need an experiment, you just need to state your opinion in a clear and concise manner. C) We know that Earth's greenhouse effect is a major factor for advanced life. Therefore, with just one example, it is possible to prove Cause and Effect. D) Advanced life forms might be rare, but we simply do not know if Earth's greenhouse effect is a major factor. With only one example, it is impossible to prove Cause and Effect. This kind of statement is not a valid scientific hypothesis because there is no test or experiment that can verify the assertion.

D) Advanced life forms might be rare, but we simply do not know if Earth's greenhouse effect is a major factor. With only one example, it is impossible to prove Cause and Effect. This kind of statement is not a valid scientific hypothesis because there is no test or experiment that can verify the assertion.

Getting to the speed of light requires enormous energy and relatively slow acceleration times. Humans would be killed by high g-forces. Which of the following is not a slower method of space colonization? A) Suspended animation ship B) Using extended human lifespan technology C) Generation ship or interstellar ark D) Nuclear powered craft that can reach 0.12c, like Project Daedalus. E) Robotic spacecraft carrying frozen early-stage human embryos.

D) Nuclear powered craft that can reach 0.12c, like Project Daedalus.

We know that only hydrogen and helium atoms were formed during the Big Bang 13.8 billion years ago. All heavier elements were formed later by nuclear fusion reactions in stars, and by supernova explosions. Chemical enrichment by stars is needed to create the elements for life, such as C, N, O, and many more. Astronomers measure the chemical abundances of the elements throughout the universe using the powerful techniques of A) Nuclear chemistry B) Astrobiology C) Microscopy D) Spectroscopy

D) Spectroscopy

Which recently launched telescope in space is expected to make a big impact on the search for life in the universe through the detailed study of many exoplanets? A) CHEOPS B) The Nancy Roman Space Telescope C) Europa Clipper D) The James Webb Space Telescope.

D) The James Webb Space Telescope.

What happens when an average low-mass star like the Sun can no longer fuse hydrogen to helium in its core? [Remember, gravity is always present, and when the heat of nuclear fusion diminishes, gravity takes over.] A) The core expands and heats up B) The helium core immediately begins fusion to make carbon C) The core cools off D) The core shrinks and heats up

D) The core shrinks and heats up

Not all stars are single. Even the nearest star to the Sun is part of a multiple star system, the Alpha Centauri triple system. We need to understand if multiple stars can still have habitable planets. Which of the following scenarios is unlikely to be a stable situation for a planet in a binary star system? A) The planet orbits one star; the radius of the planet's orbit is much smaller than the separation between the stars. B) The planet orbits both stars, but the radius of the planet's orbit is much larger than the separation between the stars. C) Each star has planets that orbit very close to the star, but the separation between the stars themselves is large enough that gravitational interference is negligible. D) The orbit of the planet is neither much larger nor much smaller than the separation between the stars.

D) The orbit of the planet is neither much larger nor much smaller than the separation between the stars.

A simplified version of the Drake Equation is also useful. The number of civilizations can be given in terms of the number of habitable planets (HP) with life as follows: Nciv = NHP x flife x fciv x fnow Here, fciv is the fraction of life-bearing planets that achieve a technological civilization at any point in time, and fnow is the fraction of possible civilizations that currently exist. What is the meaning of this last term fnow? A) The ratio of the length of time the shortest civilization exists compared to the age of possible civilizations in the Milky Way galaxy. B) The ratio of the length of time the shortest civilization exists compared to the length of time the longest civilization exists. C) The ratio of the length of time the longest civilization exists compared to the age of possible civilizations in the Milky Way galaxy. D) The ratio of the length of time the average civilization exists compared to the age of possible civilizations in the Milky Way galaxy.

D) The ratio of the length of time the average civilization exists compared to the age of possible civilizations in the Milky Way galaxy.

The challenges of observing extrasolar planets-planets beyond the solar system-are significant. Which of the following is not a relevant factor? A) Exoplanets are lost in the blinding glare of their parent stars. B) Exoplanets are at an enormous distance away from us. C) Planets don't produce any light of their own, except when young (i.e. hot). D) There are so many stars that we don't know where to start.

D) There are so many stars that we don't know where to start.

If we were to intercept a strong radio signal from outer space at 1420 MHz in binary format, this would be an example of A) a signal used for communication between a civilization's home world and another planet in its own planetary system B) a signal used for communication between a civilization's home world and a nearby star system C) a signal used for local communication on a world with intelligent beings D) an intentional interstellar signal beacon to attract attention

D) an intentional interstellar signal beacon to attract attention

Light comes from atoms. Specifically, when an electron in an atom changes its energy level and goes from a higher orbit to a lower orbit around the nucleus, the atom _______ a ________ with the corresponding energy difference. A) absorbs; electron B) absorbs; photon C) emits; electron D) emits; photon

D) emits; photon

Planet hunting technology falls into two groups: direct imaging, and indirect imaging. In the latter case, we cannot resolve the planet from the star, but we can nevertheless detect the planet's presence in another way. There are two categories of indirect detection, gravitational interactions and brightness changes. What method was used to discover Dimidium? A) The Astrometric method B) The Micro-lensing method C) None of these D) The Transit method E) The Radial Velocity or Doppler method

E) The Radial Velocity or Doppler method