Constellations and Stellar Distance

Constellations and Stellar Distance

​Constellations

• The stars in the night sky can be arranged into patterns called constellations.

• Constellations like Leo and Scorpio resemble a lion and scorpion respectively.

• Most constellations are given Latin names.

• There are 88 named constellations.

Naming Stars in a Constellation

• Stars in a constellation are named according to the Greek alphabet.

• The higher the letter in the Greek alphabet, the brighter the star.

• Alpha (α) is the brightest, followed by Beta (β), then Gamma (γ), then delta (δ) and then epsilon (ε) and so on.

• In the constellation Canis Major, Sirius is the brightest star.

Drag and Drop

A pattern of stars is also known as a ​

Placeholder

. There are ​

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named constellations. Constellations tend to resemble animals such as Leo, which resembles a ​

Placeholder

. The brightest stars in a constellation are named ​

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.

Drag these tiles and drop them in the correct blank above

constellation

88

lion

alpha (α)

conservation

scorpion

8

beta (β)

Match

Determine the 3 brightest stars in Canis Major

• Sirius

• Mirzam

• Muliphen

Alpha (α)

Beta (β)

Gamma (γ)

• Alpha (α)

• Beta (β)

• Gamma (γ)

Stellar Distance

• Space is massive, so massive that using kilometres to measure distance does not make sense

• Instead, we use light-years.

• 1 light-year is the distance that light travels in 1 year.

• If a star is 4 light-years away from Earth, it takes 4 years for that light to reach Earth.

Calculating Stellar Distance

• Speed of Light = 300 000 000 m/s

• Number of seconds in a year:

• Distance travelled by light in a year in metres:

• Distance travelled by light in a year in kilometres:

Calculating Stellar Distance

• 1 Light year = 9.5 Trillion km

  Or

• 1 Light year = 9.5 × 10¹² km

Stellar Distance

If a star was 10.3 light years away from Earth, answer the following questions. 1 light-year = 9.5 trillion km or 9.5 × 10¹² km

1. How long does is take the light to reach Earth

2. What is the distance in kilometres between Earth and the star?

Multiple Choice

A star is 5 light-years from Earth. How far away is it in kilometres?

• 47.5 trillion km

  or

  47.5 × 10¹² km

• 5 trillion km

  or

  5 × 10¹² km

• 475 trillion km

  or

  475 × 10¹² km

• 5 years from Earth