Why hasn’t the sun burned out yet?

Pedro_P

Our planet's personal space heater is incredibly efficient.

The sun is essentially a gigantic nuclear power plant.
NASA/SDO

▼ Our sun is a fairly average star in the Milky Way—not the brightest, not the biggest, and only 4.5 billion years old. It’s only uniquein that its light and heatsustains all the life on the only inhabited planet we know of in the universe. Luckily for us, it didn’t burn out before we showed up a few hundred thousand years ago. But how could it have that much fuel? Why hasn’t it been snuffed out like a candle or a campfire? And when will it finally burn out?
This was a pressing question in the 19th century, says Catherine Pilachowski, an astronomy professor at Indiana University. At the time, humans only understood two ways the sun could be generating energy: Either it was creating heat and light through gravitational contractions—pulling itself in at the center and emitting energy (in the form of heat that we feel on Earth), therefore getting smaller over time—or it was literally on fire, like the chemical reaction we see on Earth when we light a match or start a campfire. Thinking that either method could have been the sun’s modus operandi, scientists at the time calculated exactly how long the sun could have existed using both methods. But neither result squared up with what we knew the age of the solar system to be—4.5 billion years. If the sun were contracting or burning, it would have run out of fuel long before we came around. Clearly, something else was going on.
A few decades later and armed with Einstein’sfamous E = mc2, which confirmed anything that has mass must have an equivalent amount of energy, 1920s British astronomers proposed that the sun was actually converting its mass into energy.  (▪ ▪ ▪)

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dilwale

Sun gives light to all.Sunlight is source of vitamin D