Basic astronomy and night sky information
Articles about the science of astronomy and objects that are visible in the night sky.
In my latest article in Sky & Telescope magazine, we take a tour of sights along the northern Milky Way that highlight some key phases of a star’s life, both large, massive stars that burn hot and die young, as well as smaller, average-size stars like our Sun that live more stable, measured lives. Along the way, we see some spectacular sights for a small telescope for visual observing or astrophotography.
Click on the thumbnail to read the article (PDF format, 8MB).
Share This:
The first stars were big, bright, and burned out only a few million years after their formation. These stars formed out of nearly pure hydrogen and helium with no traces of heavier elements like iron and sodium found in later generation of stars, since these elements formed in nuclear reactions in the first stars themselves. None of these primordial ‘Population III’ stars exist in the local universe since they long ago exploded as supernovae. But astronomers have been searching for these first stars in distant galaxies that formed long ago. For the first time, a team of researchers have found the first signatures of these stars in a small galaxy observed with the JWST (and with the help of gravitational lensing by an intervening galaxy cluster). Neil deGrasse Tyson explains the what they found in the above video.
If you’re keen on learning more about the first stars, have a look at my feature article about stellar archaeology and the first stars published in Sky & Telescope magazine in June 2020 at this link.
Share This:
It’s a comet! No, it’s an alien spaceship! No, it’s probably just a comet. But Comet 3/I ATLAS isn’t just any comet. This speedy little visitor, which was discovered by the ATLAS survey telescope near Río Hurtado, Chile, on July 1, 2025, is only the third confirmed interstellar comet or asteroid ever observed in our cosmic neighborhood. It’s a free ‘sample delivery mission’ from another star system, and it may help reveal secrets and insights about the nature and composition of other stars and planets in the Milky Way [Read more…] about A Visitor from Beyond: Comet 3I/ATLAS Rounds the Sun
Share This:
On March 15, 1955, Albert Einstein learned of the death of his close friend Michele Angelo Besso at the age of 81. An engineer by training, Besso attended university with Einstein and worked with him at the Swiss patent office, serving as a supporter and sounding board for some of the great scientist’s early and most profound ideas. Upon hearing of his friend’s passing, and although he himself was ill with only weeks to live, Einstein sent a letter of condolence to Besso’s family in which he wrote this beguiling passage:
“Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present and future is only a stubbornly persistent illusion.”
Some might dismiss this passage as comforting words to a grieving family. But this was Albert Einstein writing, and Einstein knew a thing or two about time and space. He must have meant something here, perhaps something profound, but what? [Read more…] about Einstein, Immortality, and the Stubborn Illusion of Time
Share This:
The video above takes us on a trip around the heart – OK, the head, mostly – of the constellation Taurus – and it’s quite a ride. Based on the measured position and distance of some 11 million stars from the Gaia and Hipparchos space telescopes, this simulation from the Space Telescope Sciences Institute shows how the stars of Taurus, including the Hyades and Pleiades star clusters, change their appearance as we move in a big circle around the constellation at warp-drive speeds. This isn’t just an artist’s conception – it’s a reasonably accurate depiction in three dimensions of what we would see if we could take such a trip, and it’s quite mesmerizing as we get a glimpse of the structure of these famous clusters.
The simulation begins by showing Taurus as we see it from Earth as a V-shaped cluster of stars at the head of the celestial bull with the orange star Aldebaran marking its eye. But we see early on that Aldebaran lies much closer to us – about 65 light years – than the loose agglomeration of the Hyades which lies about 150 light years away. But we clearly see the Hyades as a bound and relatively loose star cluster that’s still holding together after 620 million years. We also see the blue-white stars of the Pleiades, about 440 light years away, as a more tightly-packed open cluster. With an age of 100 million years, its stars haven’t been tugged and pulled apart like the Hyades by the gravity of passing stars and gas clouds. The Pleiades, remarkably, appears oblong rather than spherical. This may be an artifact of measurement or perhaps a real effect. At around 0:50 in the video, we see Betelgeuse swing by. Then we see the Hyades dim slightly as it passes behind the Taurus Molecular Cloud, a dark cloud of gas and stardust where new stars are forming. Thousands more stars appear in the video, and we even see the background Milky Way thanks to star positions calculated from the other databases.
I’ve watched this video many times and pick out new details each time. We’re accustomed to seeing the sky in two dimensions, but we live in a 3D galaxy so these marvellous simulations make it easier to visualize the layout of our galactic environs. The same team also created visualization videos of the stars and dust clouds of Orion and Sagittarius, and they are well worth your time to watch and enjoy.
Share This: