Astro 120 Final exam

How far in the future will the Sun run out of fuel?

5 billion years

the Drake Equation allows astronomers to estimate...?

the number of civilizations within our galaxy with which we might communicate

Astrology and Astronomy

Differ in that astronomy is true science, but astrology is a belief system that has failed all rigorous tests.

Which air of constellations would you not expect to see in the same sky at the same time?

Orion and Sagittarius

How will other civilizations probably discover that ther is intelligent life on earth?

early television signals leaking into space

the most successful technique (so far) to find planets around other stars has been...?

photometry of start to look for variations caused by planets blocking some starlight

Which band of the electromagnetic spectrum do astronomers suggest is likely to be the best for communication between civilizations around different stars?

radio waves

What part of the sun are pressure and temperature the largest?

the center

Frank Drake was...?

the first person to search for technological civilizations around nearby stars using radio waves

What is the most important factor in determining whether or not a forming planet will end up being rocky like terrestrial planets or gaseous like giant planets?

the forming planets distance to the sun/star

What process is responsible for starting the formation of a new star?

the gravitational collapse of part of a cloud of interstellar material

What is one of the least important clues about the formation of the planets?

the outer planets have rings

Why do we strongly suspect that there is an ocean of liquid water beneath the icy surface of Europa?

the surface is broken into many pieces that resemble arctic ice fields and ice floats

the Kepler mission was designed to search for extrasolar planets using..?

the transmit method

Why do sunspots appear dark?

they are cooler than their surroundings

If every star bright enough to study with the Kepler spacecraft had an Earth-like planet in an Earth-like orbit, how many of those planets could actually be detected over the course of the 4 year Kepler primary mission?

1 in 100

In the distant future, we may find another solar system surrounding a star that is just like our Sun in every way. If a planet is found in this system at a distance of 1 AU form the star, how long might its orbital period (the planet's year) be?

1 year

the Voyager I and II spacecraft visited the Jovian planets in the 1980's and are now escaping our solar system, when will they reach the distance of the nearest star?

100,000 years

If you observe a maximum number of sunspots right now, how long would you have to wait to see the next solar maximum?

11 years

According to fossil evidence, how long ago did the first life forms develop on Earth?

3.5 billion years ago

The age of the Earth approximately

4,500,000,000

We receive a radio message from a civilization around a star about 40 light years away from Earth. If we reply right away, how long will it be between the time THEY sent the message and the time they receive our reply?

80 years

About how long has intelligent life on earth been detectable to beings on other planets of they use the same sort of tools and techniques that we are using to try to find them?

85 years or so

Approximately how much mass was there in the protoplanetary disk out of which the planets were formed, compared to the mass of the Sun?

<1%

Why was the discovery of many Jupiter-mass planets in close orbit around their most stars completely unexpected?

Giant planets have to form volatile materials (i.e. ices) which only exist far from the star.

Where in the solar system nebula would you expect to find planets like the Earth form, and why?

In the inner regions, where heavy elements can condense but ices are vaporized

If we want to observe newly formed stars (and planetary systems) embedded in an interstellar cloud, in what wavelength of light should we observe?

Infrared

The TESS spacecraft, currently looking for planets around stars, observes each star for 24-48 days. Two transits are needed to certify the discovery of a planet. If TESS finds habitable planets around a star, how will that star compare to our sun?

It will need to be cooler and less luminous than our Sun (i.e. less massive)

which new idea has been added into our theory of solar system formation as a direct result of the discoveries of extrasolar planets?

Jovian planets can migrate inward from the orbit in which they were born

What problem has precession caused for many of the schools of astronomy?

The constellations are no longer lined up with the astrological signs that are named after them; since astrology was set up, the two have slipped one sign apart.

to the best of our knowledge, what is in the habitable zone of its star?

a planet about 1.05 AU from a sun-like star

During this past few years, several news events concerned Astro 120 topics. Which of the following events did we not discuss in lecture?

a small asteroid that exploded in our atmosphere this year

We think that the life we have on Earth today originated 3.5 - 4 billion years ago, or perhaps just a bit earlier. Yet the solar system and the Earth are known to be at least 4.5 billion years old. What is one reason life as we know it had to wait until 4 billion years ago to get on it?

before then, the Earth was experiencing a period of heavy bombardment, when giant chunks of rock and ice left over from other planets forming kept hitting the Earth.

Most of the planets that have been discovered orbiting other solar-type stars have masses that are...?

between 1 and 3 Earth masses

The astrology practiced by those who cast prediction horoscopes can be tested by...?

comparing how often the predication come true to what would be expected by pure chance

One of the best proofs that our theory of how the solar system formed is correct is that astronomers now observe...?

disks around other stars which show evidence of gaps where planets may be forming

What is a "bio marker" that could be used for an observatory around a nearby star, with the right equipment, to identify the Earth as a planet with life?

free oxygen in the Earth's atmosphere

The solar system formed...

in much less than one billion years

During fusion reactions in the Sun, the four hydrogen nuclei which are fused together are more massive than the helium nucleus that they make. What happens to the missing mass?

it is converted to energy

The source of energy for the Sun is called...?

nuclear fusion

According to the giant impact model of the formation of the Moon, the collision between what two objects led to the formation of the moon?

the Earth and a Mars-size body

Some astronomers and geologist have suggested that while simple life may be common in our universe, planets hosting more advanced life is probably extremely are. Regarding this idea, what is true?

this idea set at least one of the biological factors in the Drake equation to a very low value