What process keeps a main sequence star stable and shining?

The balance between rotation and magnetic field strength The balance between inward gravity and outward pressure from hydrogen fusion in the core The constant infall of new material from the surrounding nebula The balance between heating from the core and cooling from the surface

What is the main fuel a main sequence star burns, and what does it produce?

It fuses helium into carbon, releasing energy It burns chemical fuels like hydrogen and oxygen to produce water It fuses hydrogen into helium, releasing energy in the process It breaks apart iron atoms, releasing energy

What single property of a star determines how hot it is, how bright it is, and how long it lives?

Its distance from the center of the galaxy Its age Its chemical composition Its mass

How long will a very massive star (more than 10 times the Sun's mass) spend on the main sequence?

About 10 billion years — the same as the Sun Trillions of years — their large fuel supply lasts longer Only a few million years — they burn through hydrogen very quickly About 100 million years — twice as long as a Sun-like star

Approximately how long will our Sun remain on the main sequence in total?

About 1 million years — the Sun is almost at the end of its life About 10 billion years, and it is currently about halfway through that lifespan About 100 billion years — the Sun is very young still About 1 trillion years — Sun-like stars live the longest

How long can a low-mass red dwarf star live on the main sequence?

About 1 billion years — they run out of fuel quickly because they are small About the same as the Sun — 10 billion years Trillions of years — far longer than the current age of the universe About 100 million years — they are cool and burn hydrogen slowly at first but run out fast

Why is the relationship between a star's mass and lifespan sometimes called the mass-luminosity paradox?

Less massive stars have more fuel but burn it faster More massive stars have more fuel but use it so much faster that they live much shorter lives All stars use up their fuel at the same rate regardless of mass Stars do not use fuel — they generate it through nuclear fusion

What is the Faint Young Sun paradox?

The Sun appears smaller in winter because it is farther away Young stars like the Sun are brighter than old stars, but early astronomers thought they were dim The Sun was about 70% as bright early in Earth's history, yet geological evidence shows Earth had liquid water and life Ancient humans thought the Sun was smaller because they had no telescopes

What color are the hottest, most massive main sequence stars?

Red — they glow more intensely because they are hotter Yellow — all massive stars look like the Sun Black — they absorb all light because of their intense gravity Blue-white — their extremely high surface temperatures shift their peak emission toward blue wavelengths

Which type of star is the most common in the Milky Way galaxy?

Sun-like stars (G-type yellow dwarfs) Massive blue supergiant stars Red dwarf stars (low-mass M-type stars) White dwarf stars left over from dead Sun-like stars