Blue is Hot
Kawah Ijen Volcano
Where the expression “red-hot” comes from? To work a
piece of steel, a blacksmith puts it in burning charcoals (more red) and activates
the blower until the iron becomes red hot. So red is hot, OK? End of story.
Well, maybe not. In
the good old days, we had tungsten filaments globes and power brownouts. When
this happened, the lights looked reddish brown because of low power. When the
good 240V came back, surely the lights looked white again.
Besides the blue flame
of any gas cooker, I thought of two examples of very hot blue things. The first
one is a weird volcano in Indonesia called Kawah Ijen. In most volcanoes the
lava that comes out is red-orange melted rock, or magma. This is pretty hot
stuff, 700 to 1,250 degrees C. But Kawah Ijen beats that. Its lava spits out
blue flames of burning sulphur, at about 6,000 degrees C. Most unusual.
The second one is a
star. If you look at the Western horizon after sunset at the moment, you can’t miss the Orion constellation. The brightest
star in it is a red giant called Betelgeuse. Its red hue is easily seen by
naked eye. Its surface temperature is a mere 3,200 degrees C. Our Sun is a
yellow star and shines at 5,500 degrees C. That’s better! But Orion’s second brightest star,
Rigel, takes the cake. Located opposite Betelgeuse it is a white-blue star with
a scorching 11,000 degrees. Indeed, the hottest object visible by naked eye.
References:
Kawah Ijen photo:
Orion and Rigel
https://www.timeanddate.com/astronomy/night/australia/brisbane
Comments
Post a Comment