4.1.3 Extrasolar Planets

​Extrasolar Planets
4.1.3

By Caitlin Ford

Objectives

- define what an exoplanet is with emphasis on the features of some exoplanets

- identify various factors that help in detecting extraterrestrial life

Reorder

Place the exoplanet discovery methods in order, starting with the method that has discovered the highest percentage of exoplanets and ending with the method that has discovered the lowest percentage.

• Transit - When a planet passes directly between its star and an observer, it dims the star's light by a measurable amount.

• Radial Velocity - Orbiting planets cause stars to wobble in space, causing an observable shift in the color of the star's light.

• Microlensing - Light from a distant star is bent and focused by gravity as a planet passes between the star and Earth.

• Imaging - Astronomers can take pictures of exoplanets using techniques that remove the overwhelming glare of the stars they orbit.

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Project Ozma

1960s - the first scientific attempt to search for extraterrestrial intelligent life

 

SETI program - Search for Extraterrestrial Intelligence

 

Frank Drake used radio telescopes (telescopes that pick up radio waves instead of light waves) to search for radio signals from 2 nearby stars

 

Tau Ceti & Epsilon

Drake Equation

1961 - Drake Equation is developed. This has been used as a key tool at SETI.

 

It calculates the number of intelligent civilizations that may exist in the Milky Way galaxy and be capable of communicating with people on Earth

Factors in the Equation

the rate of star formation
the fraction of stars that have planets
the number of planets per star that are capable of supporting life
the fraction of planets that actually develop life
the fraction of planets that develop intelligent life capable of communicating through technology

 

 

 

Frank Drake determined that between 1,000 and 100 million civilizations in the Milky Way could communicate through radio signals

Drag and Drop

The purpose of the Drake Equation is to estimate the probability of ​

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from ​

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Drag these tiles and drop them in the correct blank above

detecting signals

extraterrestrial intelligence

discovering planets

measuring distances

nearby galaxies

black holes

SETI

Founded in 1984.

 

Uses radio telescopes and lasers.

 

There has yet to be any definitive evidence of extraterrestrial intelligence. 

Exoplanets

Exoplanets/Extrasolar planets - planets that orbit outside the solar system.

 

1995 - the first exoplanet is discovered, 51 Pegasi b

 

There are currently over 6000 confirmed exoplanets and 9000 unconfirmed exoplanets

Exoplanet Catalog - NASA Science

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Multiple Choice

Which of these was the first SETI project?

• SETI@Home

• Drake

• Ozma

• Ozwald

Dropdown

The objective of the SETI mission is to find signals from ​

Select answer

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Great job!

Today, you learned:

- about the efforts made by astronomers to detect extraterrestrial life through SETI missions

- about the features of some interesting exoplanets