In February 2025, all seven of our planetary neighbors will be visible from Earth. So what does such a planetary alignment mean for science? Well, not much — unless you're an interplanetary ...

Find yourself a place with a good view low to the eastern horizon and be there around 11:00 EDT on Tuesday, July 23. You'll see a 90% illuminated moon slightly higher in the sky and to the right ...

When they look at sky brightness—what they call the sky background—they use a unit of brightness per area of the sky: how much light is spread out over a given parcel of celestial real estate.