1. Increasing Energy Output
If the sun were to suddenly increase its energy output for some reason, life on Earth could very well be in trouble. We survive at the sun’s leisure, being in the habitable zone where the ]Sun’s energy is neither too much or too little. If the Sun produces more energy, excess radiation could coat the Earth increasing over all heat and causing damage to the life. Solar flares could also erupt from the overactive Sun striking the Earth and disrupting electrical connections, satellite and radio transmissions.
2. Getting Too Close
If for some reason the Earth gets too close to the Sun, life can also be disrupted on Earth. This can occur if the Sun were to undergo a change and expand, becoming a red dwarf star. With its new larger dimensions, the Sun would encroach too much on the Earth. It can also happen if a large asteroid were to strike the Earth, knocking it out of its orbit and sending it towards the Sun. This may also end up sending the Earth careening into the Sun too. This latter event is much less likely to happen as the amount of force required to send the Earth out of orbit is also enough to completely destroy the planet. However, a few very rare events could push the earth out of its orbit. For example, a near miss by a large gas giant planet could exert enough gravitational pull on the Earth to pull it out of orbit.
3. Getting Too Far
Same idea as the second method above, except that the Earth is pushed away from the Sun becoming a rogue planet floating through space or at least with a much wider orbit. If the Earth were to get too far away from the Sun, all life would begin to die from lack of warmth and solar energy. Plants could not produce food with photosynthesis. Humans and other animals would die from the cold. It would also get very dark outside. This could also happen if the Sun were to suddenly decrease in volume, reducing its energy output.
4. Expansion/Super Nova
The sun will likely end all life on Earth anyway when it finally runs out of fuel to burn in a billion years or so. Presently, the sun is burning off the supply of hydrogen it has within it. When the sun runs out of hydrogen, it will begin burning helium, carbon, oxygen, iron, and nickel until the sun runs entirely out of fuel. As the sun burns these other fuels, it will begin to expand until it entirely engulfs the Earth, burning it up and destroying any life present. When the sun runs out of fuel, it will collapse and may supernova, destroying all other planets in the solar system.
5. Deadly Radiation
The Earth is provided protection from the Sun’s deadly solar wind by the electromagnetic field. This field deflects the energetic particles that the Sun emits back out into space. If this field were to disappear suddenly, the solar wind would slowly rip away the Earth’s ozone layer leaving us completely unprotected against solar rays. This would eventually harm most of life on Earth with skin damage, deadly cancer, and the death of most plant life.
About the author: Chris Keenan blogs on behalf of Spheral Solar, provider of solar air conditioner and solar units.