Science 10 with CSS teacher

Have you ever noticed that when you turn the stove on, the burner begins to glow bright red as it heats up? If you turn the heat down, the colour changes to a dull, dark red as the burner cools.

This connection between colour and temperature applies to stars as well. When you see stars in the sky, they appear whitish. However, when you look through binoculars or a telescope, their colours actually vary. Cooler stars give off reddish light, medium hot stars emit yellowish light, and very hot stars produce bluish-violet light.

Star Light, Star Bright

When you look up in the night sky, you may have noticed that some stars shine brighter than others. Are they really brighter, or are they just closer than other stars? Actually, the answer may be yes to both of these questions.

The brightness of a star is called its magnitude. Stars can be classified by their apparent magnitude (how bright they appear), or their absolute magnitude (how bright they really are). This is where their distance comes in.

Although two stars might seem to be giving off the same amount of light, one of them could be much brighter, but much further away. In this case, the two stars would have the same apparent magnitude even thought their absolute magnitudes would be different. The absolute magnitude of the stars is based on the calculation of how bright they would be if they were the same distance away; so the star that is brighter, but further away would have a greater absolute magnitude.

The classification of stars, based on their magnitude, ranges from a bright first-magnitude star to a faint a sixth-magnitude star.