For example, 400 light-years away, a star known to astronomers as SDSS J1228+1040 is a white dwarf with its gas nebula funeral shroud, and within it astronomers have found the signature of a planetesimal still orbiting its home sun long after its calamitous death.Īnd what of the Milky Way galaxy itself, the great island of stars containing our Earth and sun? By the time our sun is ballooning into the red giant phase – long before it settles down as a white dwarf – the Milky Way itself will be undergoing a long process of inevitable collision with the giant spiral galaxy next-door, the Andromeda galaxy. Ultimately that shell will dissipate off into space, and what’s left of our sun will become a white dwarf star.Įarth’s astronomers can look outward into space to glimpse of Earth’s future. Astronomers peering through telescopes in other star systems will see our sun as what we call a planetary nebula, a great shell of gas surrounding a dying star. Then the sun will blow off an envelope of gas. The red giant phase of the sun might continue for a billion years or so, but eventually the helium will run out, too. As our sun expands into the red giant phase, the habitable zone around it will be pushed outward in the solar system. At that point, the moons of the outer planets – like Jupiter and Saturn – will be the only places left in our solar system for human colonies.īut these locations, too, will be only temporary fixes in the search for a new home. Mars will take a while to heat up, but, eventually, Mars will be outside the habitable zone for humans, too. Our planet’s water and atmosphere will boil away, leaving nothing behind but a charred, lifeless rock. The outer edge of the sun will grow to reach roughly the orbit of Earth. ![]() Get one while you can!Īs the sun heats up and expands, its outer layers will envelop the innermost planets, Mercury and Venus. At that point, the sun will balloon outward to become a red giant star.ĮarthSky lunar calendars are back in stock! We’re guaranteed to sell out. At that point, the inward pressure of gravity will win out over the outward pressure of the sun’s internal fusion, until the sun heats up enough to start fusing helium. One day, the hydrogen in the sun’s interior will be depleted. This type of star is very stable for the majority of its life, quietly fusing hydrogen into helium in its interior for billions of years. Our sun is a G-type star currently about halfway through its life cycle. Our Milky Way galaxy and the Andromeda galaxy will be in the midst of a colossal collision that’ll forever alter our galactic home in space. What’s more, the death of the Earth will happen against a backdrop of change on a galactic scale. As the sun evolves, it’ll expand to become a red giant star and fry our planet to a cinder. Likewise, the sun will ruin Earth for living things, some 5 billion years from now. Calçada.Įarth exists thanks to our sun, having formed in orbit around it from a huge cloud of gas and dust in space, 4.5 billion years ago. ![]() Artist’s concept of a red giant star scorching a planet in orbit around it.
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