This isn’t a comet. It’s Asteroid (6478) Gault out in the main belt between Mars and Jupiter. So what’s it doing with a pair of tails? The longer tail stretches more than 800,000 km) and is roughly 4,800 km wide. The shorter one is roughly a quarter as long.
One theory suggests that the tiny asteroid, only 2.5 miles wide, is disintegrating as a result of long-term effects of sunlight. Sunlight? Yes, the cumulative force of the Sun’s light can slowly speed up a small body’s spin, and when spinning fast enough, it will throw off material. Pressure from sunlight very slowly began spinning up the diminutive asteroid at an estimated rate of 1 second every 10,000 years, the it may have taken 100 million years or so to get the spin rate up to a destructive level.
Image Credit: NASA