(Adopted from Universe, Ch.1, with some modifications)
| 01. | A hydrogen atom has a radius of about 5 x 10-9 cm. The radius of the observable universe is about 14 billion light-years. How many times larger than a hydrogen atom is the observable universe? Use powers-of-ten notation. |
| 02. | The Sun's mass is 1.99 x 1030 kg, three-quarters of which is hydrogen. The mass of a hydrogen atom is 1.67 x 10-27 kg. How many hydrogen atoms does the Sun contain? Use the powers-of-ten notation. |
| 03. | The diameter of the Sun is 1.4 x 1011 cm, and the distance to the nearest star, Proxima Centauri, is 4.2 ly. Suppose you want to build an exact scale model of the Sun and Proxima Centauri, and you are using a basketball 30 cm in diameter to represent the Sun. In your scale model, how far away would Proxima Centauri be from the Sun? Give your answer in kilometers, using powers-of-ten notation. |
| 04. | How many Suns would it take, laid side by side, to reach the nearest star? |
| 05. | The average distance from the Earth to the Sun is 1.496 x 108 km. Express this distance (a) in light-years and (b) in parsecs. Use powers-of-ten notation. |
| 06. | The speed of light is 3.00 x 108 m/s. How long does it take light to travel from the Sun to Earth? Give your answer in seconds. |
| 07. | When Voyager 2 sent back pictures of Neptune during its historic flyby of that planet in 1989, the spacecraft's radio signals traveled for 4 hours at the speed of light to reach Earth. How far away was the spacecraft? Give your answer in kilometers, using powers-of-ten notation. |
| 08. | At what distance would a person have to hold a nickel of 10 NT dollars (which has a diameter of about 2.6 cm ) in order for the nickel to subtend an angle of (a) 1 degree ? (b) 1 arcmin ? (c) 1 arcsec ? Give your answers all in meters. |
| 09. | Suppose your telescope can give you a clear view of objects and features that subtend angles of at least 2 arcsec. What is the diameter of the smallest crater you can see on the Moon? The average distance to the Moon is 384,000 km. |
| 10. | On January 11, 2003, the planet Venus was at a distance of 0.719AU from Earth. The diameter of Venus is 12,104 km. What was the angular size of Venus as seen from Earth on January 11, 2003? Give your answer in arcminutes and in the fraction of the Moon's average angular size. |