What is a light-year, and how is it defined?
The significance of light year and its definition.
Answer to Problem 1CQ
A light-year is a unit of length used to measure the astronomical distances. It is defined as the distance travelled by the light in
Explanation of Solution
In astronomy, there were no referent points of comparison so that standard units were created for the measurement of distances. A light-year is a unit of length which is used to describe the astronomical distances.
Therefore, a light year is the distance travelled by the light in
Want to see more full solutions like this?
Chapter 12 Solutions
Integrated Science
Additional Science Textbook Solutions
Physics for Scientists and Engineers with Modern Physics
University Physics Volume 3
Sears And Zemansky's University Physics With Modern Physics
The Cosmic Perspective (8th Edition)
The Physics of Everyday Phenomena
Conceptual Physical Science (6th Edition)
- Describe two ways of determining the diameter of a star.arrow_forwardHow Do We Know? Why is it important that a theory make testable predictions?arrow_forwardExplain the origin of the magnitude designation for determining the brightness of stars. Why does it seem to go backward, with smaller numbers indicating brighter stars?arrow_forward
- Do the previous problem again, this time using the information that the Sun is 150,000,000 km away. You will get a very large number of km as your answer. To get a better feeling for how the distances compare, try calculating the time it takes light at a speed of 299,338 km/s to travel from the Sun to Earth and from Alpha Centauri to Earth. For Alpha Centauri, figure out how long the trip will take in years as well as in seconds.arrow_forwardIs the Sun an average star? Why or why not?arrow_forwardWhich of the following statements about stellar parallax is true? A. We observe all stars to exhibit at least a slight amount of parallax. B. Stellar parallax was first observed by ancient Greek astronomers. O C. The amount of parallax we see depends on how fast a star is moving relative to us. D. It takes at least 10 years of observation to measure a star's parallax. OE. The closer a star is to us, the more parallax it exhibits.arrow_forward
- Problem 5. Imagine that you observe a star field twice, with a six-month gap between your observations, and that you see the two sets of stars shown below. Which do you think is closest to the observer? Figure 1: Schematic of image of stars A,B, and P taken six months apart. Problem 6. Suppose the angular separation between stars A and B is 0.5 arcseconds. How far would you estimate star P to lie from the observer?arrow_forwardUse the circumference and speed to figure out how long the Sun takes to go once around the Galaxy (the Sun's period, sometimes called the "galactic year.") Give your answer in Earth years. Be careful with your units.arrow_forwardWhich of the following WOULD NOT characterizes the type(s) of star we would find at g, m, n, o, and p on the Hertzsprung-Russel Diagram (Figure 4) a. are all smaller than q,i,h. b. fuse hydrogen into helium. c. are called, “the main sequence”. d. fuse He into heavier elements. e. get smaller towards the right sidearrow_forward
- In your own words, describe the difference between apparent magnitude and absolute magnitude. Explain the relationship between apparent magnitude, absolute magnitude and distance.arrow_forwardIf we view a star now, and then view it again 6 months later, our position will have changed by the diameter of the Earth's orbit around the sun. For nearby stars (within 100 light-years or so), the change in viewing location is sufficient to make the star appear to be in a slightly different location in the sky. Half of the angle from one location to the next is known as the parallax angle (see figure). Parallax can be used to measure the distance to the star. An approximate relationship is given by d = 3.26 p , where d is the distance in light-years, and p is the parallax measured in seconds of arc. Vega is a star that has a parallax angle of 0.13 second. How far is Vega from the sun? Note: Parallax is used not only to measure stellar distances. Our binocular vision actually provides the brain with a parallax angle that it uses to estimate distances to objects we see. (Round your answer to two decimal places.) light-yearsarrow_forward
- An Introduction to Physical SciencePhysicsISBN:9781305079137Author:James Shipman, Jerry D. Wilson, Charles A. Higgins, Omar TorresPublisher:Cengage LearningAstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
- Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage LearningHorizons: Exploring the Universe (MindTap Course ...PhysicsISBN:9781305960961Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning