When you think of objects close to the sun, Mercury, the solar system's innermost planet, probably comes to mind. But has any other object — natural or artificial — gotten closer to our star? And what's the closest an object has gotten to the sun while still escaping?Many objects have reached much closer than Mercury, including asteroids, comets and spacecraft, experts told Live Science.At its closest point to the sun, called perihelion, Mercury comes within 29 million miles (47 million kilometers) of our star, according to NASA. But several known asteroids come even closer. Scott Sheppard, an astronomer at Carnegie Science, an independent research institute in Washington, D.C., said such as...