The birth of a star: Formed from a nebula
Nuclear fusion powers stars
Structure of our sun
Life cycle of a star
nebula -> red giant -> collapse -> nova -> white dwarf -> dead star
nebula -> supergiant -> collapse -> supernova -> neutron star
nebula -> supergiant -> collapse -> supernova -> black hole
Hubble Space telescope
The night sky tonight
The night sky tonight (another source)
List of constellations
Are constellations really groups of stars? (i.e. Stars actually near each other)
Or are constellations really illusions? (i.e. Stars actually are far apart, and only appear to be near each other, when seen from Earth.)
Constellations are an illusion
From Earth, stars in a constellation appear to be close to each other.
We tend to think that the stars are all at the same distance from us.
But it’s an illusion! In most cases, the stars of a constellation are located at different distances.
Let’s look at Orion the Hunter. Can you tell which star is the farthest? Which is the closest?
Red-colored Betelgeuse (upper left shoulder) and blue-colored Rigel (lower right leg) are the two brightest stars of Orion.
Yet just because a star is the brightest, doesn’t mean it’s the closest. You can’t tell its distance based on its appearance.
The farthest star in Orion is Alnilam, the middle belt star, at 1,359 LY (light-years, the distance light travels in a year.)
There’s 6 trillion miles in one light-year.
The closest is Bellatrix, the upper right shoulder star, at a distance of 243 LY.