June 4, 2023
Saturday, June 4, 2023
Venus is at “greatest eastern elongation” tonight, meaning it is at its farthest angular distance from the sun on our sky. It is also now close enough to us in its orbit that the geometry of its position with respect to the sun makes it appear as a crescent phase in binoculars or telescopes. Some youngsters with super-sharp eyes may not need the binoculars or telescope to notice the crescent shape of Venus but the rest of us certainly do. Venus is a bit brighter than last month and will get even brighter throughout June as it draws closer to Earth in its faster, inner orbit. Venus is bright enough that you can see it even during the day if you know right where to look.
Next week Monday, June 12, Venus will pass above the Beehive Cluster at the heart of Cancer. You’ll need binoculars to pick out the stars of the Beehive. At the beginning of June, Mars was right above the Beehive. Tonight Mars is about a thumb width at arm’s length to the left of the Beehive. This spring Venus has been racing eastward to try to catch Mars. However, the orbital positions of Earth, Venus, and Mars this time mean that Venus will get close but not meet up with Mars. The closest they’ll get to each other is at the last day of the month when they’ll be 3.5 degrees from each other on the sky (almost two knuckles at arm’s length). That’ll be close enough, though, to comfortably fit within the same field of view of your binoculars.
Last night, the moon was at full phase. On the night of June 10, the moon will be at last (or third) quarter phase, rising around 1 a.m. The following several days, the moon will be a thinner and thinner waning crescent phase. Early risers will be able to see the waning crescent moon next to the brilliant Jupiter in the pre-dawn sky on June 14. It’ll be a beautiful sight to the naked eye and even better with binoculars. Much closer to the horizon, you might be able to spot Mercury which rises shortly before the sun does.
My previous column mentioned a recent observation by the James Webb Space Telescope of a young nearby star that has its proto-planetary dust disk still around it. A more recent discovery using the Webb is also of young objects but these are galaxies seen as they were billions of years ago. A team led by Erica Nelson from the University of Colorado announced the discovery of a class of galaxies that have not been seen before. They are very red and quite flat.
The galaxies are filled with so much interstellar dust that all of the visible light is blocked, making them invisible to the Hubble Space Telescope. They are also at a great distance from us, which means that the expansion of the universe has stretched much of the light to the longer wavelengths of infrared. Most flat disk galaxies have a central bulge but these strange galaxies seem to be lacking the usual central bulge. Now that we have found the galaxies, large ground-based microwave and radio telescopes and Webb-based spectroscopy might be able to tease out what’s happening inside these peculiar young galaxies.
Closer to home, the new Daniel K. Inouye Solar Telescope (DKIST) has been returning some stunning images of the sun. DKIST is the largest solar telescope in the world and it is located at the Haleakalā Observatories site on the island of Maui, Hawaiʻi. With a mirror that is four meters across, DKIST is able to spot details that were too blurred out in previous telescopes. Although, first light was back in 2019, the first science observations have only been within the past year. The latest batch of images released to the public show super-fine structure in sunspots and the dark boundaries of the granules formed by small-scale convection in the sun’s surface (well, small-scale compared to the sun—they are only several hundred miles across). In the atmosphere layer just above the surface, called the chromosphere, we can see dark, elongated fibrils shaped by the sun’s magnetic field. The high-resolution observations by DKIST will help us understand the connection between the sun’s magnetic activity and the solar storms that can wreak havoc on our satellites and upper atmosphere.
I hope you’ll be able to experience a truly dark sky filled with thousands of stars this summer!