The night sky twinkled long before the rise of humans, and its lights will remain much the same far into our future.
In other words, our lives are mere flashes compared to the monolithic lifespan of a star.
Do you have what it takes to ace a quiz on these stellar big-timers? With less than a century's worth of life in you, are you sure you even have time?
by Robert Lamb, HowStuffWorks
Stars are born when enough gas and dust bunches together, heats up and begins fusing hydrogen into helium.
What generally gets the party started?
Planets drifting into clouds of gas
Supernova shock waves
Nothing -- gas and dust combine on their own
Superman
When hefty stars (about nine times more massive than our sun) die, they go out with a real bang: a supernova.
The blast squishes together nearby gas and dust, often enough to pull in more material via gravity. The next thing you know, you have a fledging protostar on your hands.
Protostars may have a bright future, but don't start producing energy until they heat up to about 7 million degrees Kelvin.
What reaction is responsible for this energy production?
Hydrogen atoms fuse into helium
Helium atoms fuse into hydrogen
Leftover heat in the gas and dust
Hydrogen atoms split to create nuclear power
Stars are powered by nuclear fusion -- not fission (which is what nuclear reactors work on).
Two hydrogen atoms fuse together, creating hydrogen and a lot of energy. As the star ages over millions of years, more matter drifts into the young star's heart, increasing its internal temperature.
A protostar's future hinges on its weight -- 1/10th of a solar mass or greater, to be precise.
If it fails to pass this hurdle, what does the star become?
White dwarf
Red dwarf
Blue dwarf
Brown dwarf
There's a colorful array of dwarfs out there in the cosmos, but only one is the fate of stunted young stars.
These sub-stellar objects are stars that failed to live up to a bigger companion's potential. They produce very little light, giving them a brownish-red hue.
Underachieving protostars grow up to be lowly brown dwarfs, but the rest are destined for stardom.
When there's enough mass to keep nuclear fusion going, a huge release of gas occurs. This "belch" of a new star is called:
Pyroclastic flow
Bipolar flow
Chiastic slide
Solar flare
As the protostar grows up, it releases a massive jet of gas called a bipolar flow. Some of the material blasted outward ends up forming future planets, moons, asteroids and comets.
The intense, explosive energy of fusing hydrogen pushes outward against the crushing weight of a new star's gravity.
Its life directly depends on the amount of hydrogen on hand to fuse into helium.
The greater the mass, the longer it will burn. How much longer can the sun keep its fire burning?
Five million years
Five billion years
Ten billion years
Forever!
The sun is already more than 4.5 billion years old, so you'd better be glad A isn't the answer.
Based on its mass and intensity, scientists think the sun's tank won't hit empty until it reaches its 10 billionth birthday.
Not even a star can escape death. When there's no more hydrogen to fuse into helium, it can't produce the energy it needs to outdo its own gravity.
What happens when a star -- anywhere from a half to 10 masses of the sun -- collapses?
Swells into a red giant
Collapses into a black hole
Becomes a brown dwarf
Splits into two or more protostars
You can think of that swelling as a kind of death spasm before the big sleep. The collapse crushes the star's core, generating enough heat to blow out the outer layers for millions of miles.
One day, the sun will bloat into a red giant large enough to swallow Mercury, Venus and probably Earth.
A red giant's core becomes hot enough to fuse helium into carbon. For stars like our sun, this is the last hurrah before cooling and shrinking into a white dwarf, then a dim black dwarf. Larger stars, however, keep the cycle going and fuse elements into heavier and heavier forms, such as oxygen, neon and silicon.
Which element is the final straw for stars?
Magnesium
Sulfur
Iron
Finalstrawium
Once a massive star gets through successive rounds of fusion to an iron core, there's nothing else it can really do but collapse forever.
Bummer.
The constriction of a large star's iron core heats things up a lot.
Only this time, the star doesn't just swell... it explodes in a massive supernova, lighting up whole galaxies and seeding the cosmos with gold, platinum, uranium and other heavy elements.
If you were to recreate this kind blast on Earth, how many conventional explosives would you need?
10 megatons of TNT
102 megatons of TNT
10^28 megatons of TNT
All the cherry bombs in Texas
According to NASA, the average supernova is equal to 10^28megatons of TNT.
That's a few octillion nuclear warheads worth of energy -- a truly astronomical figure, if there ever was one.
A supernova stirs up new stars with its shock waves and spreads elements through space.
The remains of its core either compress into a tightly packed neutron star or collapse into a singularity to form a black hole, depending on its mass.
Which of the following isn't a suspected variety of black hole?
Supermassive black hole
Supermissive black hole
Schwarzschild black hole
Kerr black hole
Schwarzschild black holes rotate, and Kerr black holes don't. Supermassive black holes are exactly what they sound like: enormous black holes that make up the center of galaxies.
If a supermissive black hole existed, we can only assume it would exist on the pages of written correspondence. Look out, post office.
We can tell a lot about a star by its color, especially its average temperature.
Which of these colors indicates the hottest star?
Orange
Blue-violet
Blue-white
White
Burning at around 30,000 degrees Kelvin, blue-violet stars are designated as spectral class O, the hottest active stars in the sky.
The lowest rating, class M, refers to stars that burn red-orange at a mere 3,000 degrees Kelvin. Brrr! (just kidding)
Brown Dwarf
Better luck next time, sparky!
White Dwarf
Thing is, you're more or less a burnout among fusing gas balls that are bigger, brighter and more glorious than you. Darn.
Main-sequence
Not the top of the list of bright stars, but not at the bottom either.
Blue supergiant
Universe, look out.
Black hole
You're set to continue raking in the stellar know-how for trillions of years.
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