It will burn as a red giant star for another billion years and then collapse into a white dwarf star. All rights reserved. Characteristics of the sun The sun resides some 26, light-years from the Milky Way's center, in a tendril of our home galaxy known as the Orion Arm. ALMA - Protoplanetary disks. Share Tweet Email. Why it's so hard to treat pain in infants. This wild African cat has adapted to life in a big city. Animals Wild Cities This wild African cat has adapted to life in a big city Caracals have learned to hunt around the urban edges of Cape Town, though the predator faces many threats, such as getting hit by cars.
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The debate on what is the farthest star you can see with an unaided eye is still ongoing. This question, believe it or not, is surprisingly difficult to answer, and here is why:. All these stars, even the nearest ones, are extremely distant.
In comparison, our own Sun is [on average] only 93 million miles away from the Earth. The sunlight travels at…well…the speed of light [ miles per second], and takes about 8 minutes and 20 seconds to cover that vast distance. But does that mean the sunlight we see is 8 minutes and 20 seconds old? The photons are born in a nuclear fusion, when hydrogen cores smash together to make helium.
As a byproduct of this reaction, a huge amount of energy is released in the form of photons. But those are not visible light photons, not the kind of light our eyes can see, but high energy gamma-ray photons. The Sun is composed of different layers, like an onion.
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. As the planet heats up, the water on the surface of our planet will begin to evaporate.
This change is a sufficient increase in energy to change the location of the habitable zone around our star. The habitable zone is defined as the range of distances away from any given star where liquid water can be stable on the surface of a planet.
This will mark the beginning of the evaporation of our oceans. By the time the sun stops burning hydrogen in its core , Mars will be in the habitable zone , and the Earth will be much too hot to maintain water on its surface. Predictions of exactly how rapidly this process will unfold depend on who you talk to. Most models suggest that as the oceans evaporate, more and more water will be present in the atmosphere instead of on the surface.
This will act as a greenhouse gas, trapping even more heat and causing more and more of the oceans to evaporate, until the ground is mostly dry and the atmosphere holds the water, but at an extremely high temperature. As the atmosphere saturates with water, the water held in the highest parts of our atmosphere will be bombarded by high energy light from the sun , which will split apart the molecules and allow the water to escape as hydrogen and oxygen, eventually bleeding the Earth dry of water.
Where the models differ is on the speed with which the earth reaches this point of no return. Some suggest that the Earth will become inhospitable before the 1 billion year mark, since the interactions between the heating planet and the rocks, oceans, and plate tectonics will dry out the planet even faster. Others suggest that life may be able to hold on a little longer than 1 billion years, due to the different requirements of different life forms and periodic releases of critical chemicals by plate tectonics.
The Earth is a complex system — and no model is perfect. However, it seems likely that we have no more than a billion years left for life to thrive on our planet. Explore further. More from Astronomy and Astrophysics. Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below please adhere to guidelines.
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By using our site, you acknowledge that you have read and understand our Privacy Policy and Terms of Use. As the Sun matures into a Red Giant, the oceans will boil and Earth will become uninhabitable.
Magnificent coronal mass eruption. Source: The Conversation. Citation : The sun won't die for 5 billion years, so why do humans have only 1 billion years left on Earth?
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