Exam 1: Astronomy and the Universe

Light from a campfire lit by Roman centurions in the year 100 B.C.E. travels out into space at the speed of light. Which is the farthest of the 20 brightest stars (See Appendix 5, Universe, 11th ed.) beyond which this light will now have traveled?

The distance to the star τ Scorpii has been measured as 230 pc. Expressed in light-years, this is approximately:

Which unique quality distinguishes human beings from other living things?

The star ? Puppis is about 750 pc from Earth. Expressed in light-years, this is approximately:

One foot is the same distance as:

How great a distance is 1 light second, the distance light travels in 1 second?

In our exploration of the solar system, we have sent spacecraft intended to land on or fly past:

The Orion Nebula is shown in Figure 1-7 of Universe, 11th ed. How long has the light been traveling from this object before it arrives on Earth? ​ ​

The lifetime of our Sun is estimated to be about:

The distance from Earth to the star Betelgeuse (in the constellation Orion) has been measured as 520 light-years. Expressed in parsecs, this is approximately:

What is the distance between Earth and the nearest star? (Think carefully about your answer!) (Check the list of stars in the Appendix 4 of Universe, 11th ed.) ​ ​

A circle of radius 10m has a circumference C = 2πR = 62.83 m. A 30° angle would intercept an arc that is 30/360 or 1/12 of this, namely 5.24 m. What does this result (along with the result in the previous problem) suggest about the validity of the formula derived in Box 1-1? [Note to instructors: This question and the previous one are intended to reinforce concept that the small angle formula computes subtended arc length, which is slightly greater than D in Box 1-1 for large angles, but a reasonably good approximation for small angles.]

What is the approximate angular diameter of the Sun in arcseconds?

In 2018, an inhabitant of a planet orbiting a distant star observes the flash of the first nuclear explosion on Earth, which occurred in July 1945. Approximately how far away is his solar system from Earth?

The lifetime of a typical star (like our Sun) appears to be:

The time taken for light to travel from Jupiter to Earth when they are closest to each other is (you need to think carefully about this, and draw a diagram):

The most important reason for exploring other planets is that:

The star $\gamma$ Aquilii is 340 ly from Earth. Expressed in parsecs, this is approximately:

10 × 10⁵ =

A globular cluster of stars is measured to have an angular diameter of 20.6 arcseconds, and its distance from Earth is measured to be 200,000 light-years. What is its approximate physical diameter in light-years?