NASA has gone dark just hours before humans get the closest look at the mysterious object barreling through our solar system. The interstellar object dubbed 3I/ATLAS will come within 18 million miles of Mars on October 3, its closest flyby of any planet this year. However, when those readings come in, America's space agency may remain completely silent about what the object really is. Harvard astrophysicist Avi Loeb has maintained that 3I/ATLAS has too many confounding characteristics to be a simple comet streaking through the solar system. However, NASA has noted that it could be as small as 1,444 feet in length, which is still considered a 'city-killer' if it were to strike Earth.