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Today's global warming is nothing compared to what astronomers have just seen through the time machine of a telescope.<br /><br />The most detailed look ever at the environments very near the surfaces of several aging and bloated stars reveals a potentially - future for Earth. Because the stars are older versions of the one that gives us warmth, the measurements help astronomers envision what will happen in a few billion years, when the swollen Sun will scorch Earth.<br /><br />The dying objects are called Mira stars, for one of the most famous of the bunch. They are part of a broader class of object known as red giants, which include the popular skywatching targets Betelgeuse (often pronounced "beetle juice") and Antares, both considered red supergiants.<br /><br />Mira stars have nearly exhausted the hydrogen that powers their thermonuclear furnaces. Each is swelled to a diameter that is larger than the orbit of our home planet. The aging stars pulsate, expanding and contracting every year or so. <br /><br />When our Sun begins to pulsate, the surface temperature on Earth will periodically climb to 5,400 degrees Fahrenheit (3,000°C), said Guy Perrin, a Paris Observatory researcher who led the new study. <br /><br />"The direct consequence is that no life will be possible by then on Earth," Perrin told SPACE.com . "But this is in a few billion years from now."<br /><br />It is also one reason why Perrin and his colleagues eagerly study Mira stars, whose intense activity has prevented views of their surfaces.<br /><br />The new work combined several telescopes to effectively create one large observatory in a technique called interferometry, allowing a look at each stars photosphere, the area just above the surface.<br /><br />"During these pulsations, Mira stars lose a lot of mass to the interstellar medium," Perrin explained. Material equal to about a third of the Earth is pumped into interstellar space with each pulsation. Scientists don't know exactly how all this works.<br /><b></b>