The Sun's angular diameter, as observed from Earth, is approximately 0.5°. This is based on Earth's average distance of 93 million miles (150 million km) from the Sun. From Mercury, at an average ...

You know I like to use pictures for data from time to time, right? One problem is that I don't know much about cameras. There, I said it. Really, almost all of my photos are made with my phone. That ...

Forbes contributors publish independent expert analyses and insights. The Universe is out there, waiting for you to discover it. Intuitively, we all know that when we see an image of an object, it ...

Elongation is the angle, in degrees, between the Sun and the planet as seen from here on the Earth. Superior planets (those that lie further from the Sun than us: Mars, Jupiter, Saturn, Uranus, ...

I love this question from Youtuber Marques Brownlee, who goes by MKBHD. He asks: "What is a photo?" It's a deep question. Just think about how early black-and-white film cameras worked. You pointed ...

If you were to compare planet Earth to the Sun, you'd find that you'd have to stack 109 Earths atop one another just to go from one end of the Sun to the other. Yet there are stars out there that are ...

Phobos is the best known irregular satellite in our solar system, but it isn't a squoon. (ESA/DLR/FU Berlin (G Neukum), CC BY-SA 3.0 IGO) Well let’s think about the physics: for a satellite to be ...

In my January column, I challenged readers to look for some of the finest naked-eye features on the Moon during lunar perigee — when the Moon is closest to Earth in its elliptical orbit. But have you ...

THE existence of a source in the Crab Nebula with an angular diameter of less than 1 sec of arc has been revealed by observations of interplanetary scintillation at a frequency of 38 Mc/s (ref. 1).