We look at the age of the whole solar system, because it all came together around the same time. To get this number, we look for the oldest things we can find. Moon rocks work well for this. When astronauts brought them back for scientists to study them, they were able to find out how old they are.
If our Sun is four and a half billion years old, how much longer will it shine? Stars like our Sun burn for about nine or 10 billion years. So our Sun is about halfway through its life.
It still has about 5,,,—five billion—years to go. When those five billion years are up, the Sun will become a red giant. Dark molecular isomers lit up using optical cavities 1 hour ago. Question about Kuiper belt 2 hours ago. Temperature of gas in a cluster 8 hours ago. Level of details in prime focus vs eyepiece images Nov 10, Maximum mass of a neutron star Nov 09, Related Stories. Some potentially habitable planets began as gaseous, Neptune-like worlds Jan 28, Jan 05, Dec 11, What is a Wolf-Rayet star?
Feb 06, Dec 19, Dec 04, Recommended for you. Astronomers discover a sub-Neptune exoplanet orbiting nearby star 22 hours ago. Nov 11, Nov 10, Data from the Fermi Large Area Telescope suggests there is a particle accelerator in the galactic center Nov 10, Load comments Let us know if there is a problem with our content. Your message to the editors. Your email only if you want to be contacted back.
Send Feedback. Thank you for taking time to provide your feedback to the editors. E-mail the story The sun won't die for 5 billion years, so why do humans have only 1 billion years left on Earth? Your friend's email. Your email. I would like to subscribe to Science X Newsletter. Learn more. Your name. Note Your email address is used only to let the recipient know who sent the email. Your message. The hottest and the densest part of the Sun is the core. This is where all the nuclear fusion magic happens.
Surrounding the core is the radiative zone. It extends from 0. As we move through the radiative zone, the temperature drops by about an order of magnitude, from 15 million degrees C in the core to to 2 million degrees C on the outer edge of the radiative zone. The density drops too. Further out is the convective zone. It extends all the way to the visible surface.
Radiative and convective zones got their names from the way the energy is being transferred through each zone, i. In between the two zones is tachocline, a thin [but very important] interface area. Finally, the outermost part of the Sun is the atmosphere. Our photon loses a lot of energy to these collisions, becoming first X-ray and then UV photon. Through this continuous random bouncing back and forth no wonder that mathematically this problem is known as random walk , up to a million years after it was born, our photon finally enters the convective zone.
Our photon hitches a ride in one of these bubbles up to the visible surface. The sunlight we see is years and 8. It is ancient!
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