Q 01/05

The Sun's diameter is 400 times the Moon's. By what factor is the Sun farther from Earth, which is why the two look the same size in our sky?

A) 400

B) 40

C) 4,000

D) 100

Answer · why

A) 400

That coincidence gives both bodies an apparent size of about half a degree, so the Moon can just cover the Sun's disk.

Q 02/05

What is the theoretical maximum length of totality during a solar eclipse?

A) 5 min 10 s

B) 2 min 40 s

C) 4 min 28 s

D) 7 min 32 s

Answer · why

D) 7 min 32 s

The longest one between 3000 BC and 8000 AD comes on July 16, 2186 and will run 7 min 29 s.

Q 03/05

In which kind of solar eclipse does the Moon appear too small to cover the Sun, leaving a bright ring?

A) Hybrid

B) Partial

C) Annular

D) Penumbral

Answer · why

C) Annular

It happens when the Moon is near the far point of its orbit. A hybrid eclipse shifts between annular and total along its path.

Q 04/05

What is the name of the dark central part of the Moon's shadow, inside which a total eclipse is seen?

A) Penumbra

B) Umbra

C) Antumbra

D) Corona

Answer · why

B) Umbra

It is typically only 100-160 km wide on the ground, while the penumbra, where the eclipse is partial, spans more than 6,400 km.

Q 05/05

Which part of the Sun becomes visible to the naked eye only during a total eclipse?

A) The corona

B) The photosphere

C) The core

D) The chromosphere's spots

Answer · why

A) The corona

It is the outer atmosphere, normally drowned out by the far brighter photosphere.