Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 8: Problem 22

What is the radial velocity method used to detect planets orbiting other stars? Why is it difficult to use this method to detect planets like Earth?

Short Answer

Expert verified
The radial velocity method is a method for detecting planets by observing the shifts in the star's spectral lines due to the star's movement (caused by the planet's gravitational pull). However, detecting Earth-like planets is challenging as the shifts caused by an Earth-like planet are minuscule, and therefore, require extremely precise measurements.

Step by step solution

01

Understand the Radial Velocity Method

The radial velocity method is a way to detect the presence of planets around a star. The gravitational tug of a planet orbiting a star causes the star to move in a small 'circle', shifting forwards and backwards. As the star moves towards us, its light shifts towards the blue end of the spectrum (blue-shifted). Conversely, when the star moves away from us, the light shifts towards the red end (red-shifted). By observing these shifts, astronomers can extrapolate information about the planets that are causing them, including their mass and orbital period.
02

Challenges of Radial Velocity Method

Detecting Earth-like planets using the radial velocity method is difficult due to a few reasons. Firstly, the orbit of the Earth around the Sun causes it to move at a speed of about 30 kilometers per second. However, our Sun only moves at a speed of about 9 centimeters per second due to the Earth's gravitational pull, which is much slower in comparison. Secondly, the red and blue shifts caused by an Earth-like planet are so small that they are hard to measure. For example, Earth would only cause the Sun's light to shift by a maximum of 0.1 parts per million. Therefore, very precise measurements are required, making it difficult to detect Earth-like planets.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

What is meant by a substance's condensation temperature? What role did condensation temperatures play in the formation of the planets?

Explain why most of the satellites of Jupiter orbit that planet in the same direction that Jupiter rotates.

If hydrogen and helium account for \(98 \%\) of the mass of all the atoms in the universe, why aren't the Earth and Moon composed primarily of these two gases?

Use the Stamy Night Enthusiast \({ }^{\mathrm{TM}}\) program to investigate stars that have planets orbiting them. First display the entire celestial sphere (select Guides > Atlas in the Favourites menu). Then use the Find pane to find and center each of the stars listed below. To do this, click the magnifying glass icon on the left side of the edit box at the top of the Find pane and select Star from the dropdown menu; then type the name of the star in the edit box and press the Enter or Return key on the keyboard. Click on the Info tab on the left-hand side of the Starry Night Enthusiast 'M window for full information about the star. For each star, record the luminosity of the star (a measure of the star's total light output). How far from Earth is each star? Which stars are more luminous than the Sun? Which are less luminous? How do you think these differences would have affected temperatures in the nebula in which each star's planets formed (see Figure 8-10)? (i) 47 Ursae Majoris; (ii) 51 Pegasi; (iii) 70 Virginis; (iv) Rho Coronae Borealis.

Suppose that a planetary system is now forming around some protostar in the sky. In what ways might this planetary system turn out to be similar to or different from our own solar system? Explain your reasoning.
See all solutions

Recommended explanations on Physics Textbooks

Magnetism

Read Explanation

Solid State Physics

Read Explanation

Conservation of Energy and Momentum

Read Explanation

Electromagnetism

Read Explanation

Geometrical and Physical Optics

Read Explanation

Fluids

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free