Welcome to Perihelionrth’s orbit around the Sun is not a circle, it’s an ellipse. The point along its elliptical orbit where our fair planet is closest to the Sun is called perihelion. This year perihelion is today, January 4, at 13:28 UTC, with the Earth about 147 million kilometers from the Sun. For comparison, at aphelion on last July 3 Earth…Read More

Eclipse Pairclipses tend to come in pairs. Twice a year, during an eclipse season that lasts about 34 days, Sun, Moon, and Earth can nearly align. Then the full and new phases of the Moon, separated by just over 14 days, create a lunar and a solar eclipse. But only rarely is the alignment at both new moon and full moon phases during a single…Read More

Solar Analemma 2024Recorded during 2024, this year-spanning series of images reveals a pattern in the seasonal drift of the Sun’s daily motion through planet Earth’s sky. Known to some as an analemma, the figure-eight curve was captured in exposures taken only at 1pm local time on clear days from Kayseri, Turkiye. Of course the Sun’s position on…Read More

Alpha Centauri: The Closest Star SystemThe closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest — called Proxima Centauri — is actually the nearest star. The bright stars Alpha Centauri A and B form a close binary as they are separated by only 23 times the Earth- Sun distance – slightly…Read More

The Twisted Disk of NGC 4753What do you think this is? Here’s a clue: it’s bigger than a bread box. Much bigger. The answer is that pictured NGC 4753 is a twisted disk galaxy, where unusual dark dust filaments provide clues about its history. No one is sure what happened, but a leading model holds that a relatively normal disk galaxy g…Read More