Science of Astronomy

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

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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.

 

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Like most stars in the Milky Way, our Sun was born in a cluster of hundreds of new stars in a cloud of glowing gas and dust like the Orion Nebula, then settled down with its siblings in an open star cluster like the Pleiades.  Over the next few hundred million years, as it made its way around the Milky Way, this new cluster of stars was slowly pulled apart by tidal forces and the gravitation pull of passing dust clouds.  Some of the family members may have traveled together for another billion years as a stellar association or a moving group. But like human siblings, they were eventually separated once and for all by the vicissitudes of the outside world. [Read more…] about Our Sun’s Lost Sibling

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Enjoy this spectacular new artist’s animation of the Milky Way Galaxy based on data from ESA’s Gaia space telescope. Gaia has changed our impression of the Milky Way. Even seemingly simple ideas about the nature of our galaxy’s central bar and the spiral arms have been overturned. Gaia has shown us that it has more than two spiral arms and that they are less prominent than we previously thought. In addition, Gaia has shown that its central bar is more inclined with respect to the Sun. No spacecraft can travel beyond our galaxy, so we can’t take a selfie, but Gaia is giving us the best insight yet of what our home galaxy looks like. Once all of Gaia’s observations collected over the past decade are made available in two upcoming data releases, we can expect an even sharper view of the Milky Way.

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