The Stars at Night, Are They Bright?

Maybe if you’re deep in the heart of Texas!

Seriously, that’s a question with a ‘depends’ answer.

It depends on the stars distance from Earth. Take Sirius for example. It’s the brightest star in our sky and relatively close at 8 light years from Earth. Another star, Rigel in Orion is 800 light years away from us and doesn’t appear as bright as Sirius. Of course, it’s way farther away so it shouldn’t be as bright, eh? Yes, but Rigel is about 35x the size of Sirius and is intrinsically brighter. If Rigel were the same distance from us as Sirius, it would be blindingly bright in our sky. That’s how distance affects a star’s apparent brightness as viewed from Earth.

It depends on the star’s intrinsic brightness, as mentioned above. Intrinsic brightness does not depend on the stars size as much as its surface temperature, but size does come into play. In general, large young stars are brighter intrinsically than large old stars. A large young star is typically a massive star, 5+ times more massive than our Sun. Greater mass comes from more hydrogen and that in turn results in fusion so furious the star shines with a blue-white light. These stars make the Sun seem cool and dim by comparison. Aldebaran in Taurus is a large old star, 65 light years away, about the mass of our Sun. It has lower intrinsic brightness but it’s bright in the night sky because it is 44 times the size of our Sun. Large old stars are usually the evolutionary stage of yellow dwarf stars like our Sun, relatively cool and dim, and called red giants. They limp along, puffing off gas and dust as fusion sputters, like an old car with bad spark plugs and burning oil.

Getting back to deep in the heart of Texas.

It depends on your location. It’s getting harder and harder to avoid the effects of bad nighttime outdoor lighting. It’s taking longer and longer to find places free from light pollution. Think of it, 80% of the North American population cannot even see the Milky Way at night. Deep in the heart of Texas countryside it’s a marvel! It will make you weak in the knees when you see it. From semi-rural places like Canyon Lake the Milky Way is becoming a fading memory. Developers illuminate paradise, aim spotlights into the sky because it ‘looks good’. Billboards – the same, spotlights pointed up. Malls, gas stations…the same – spotlights into the sky.

I guess they are either trying to attract people, like moths, or looking for enemy aircraft!

What’s in the Sky?

Check out this site, called The Stars at Night. Elizabeth Buckley (Director) and her crew have created a documentary about the history, lore, and personal meaning of the stars in our sky.

https://www.thestarsatnight.org/

Full (Snow or Hunger) Moon occurs on February 5th.

February 6; night; nearly overhead: Comet C/2022 E3 will appear close to Capella, the bright star in Auriga, the Charioteer. Use binoculars or telescope.