Astronomy July 2021

easy deep-sky observing

When I first started observing the sky, I was astonished that you could simply walk outside, set up a small telescope, and look far away into the heavens. Astronomy is one of the few sciences in which amateurs — pure lovers of the sky — can share the same laboratory, the universe itself, with the professionals. Over the past couple of decades, with the availability of larger and larger backyard scopes and an information revolution, advanced deep-sky observers have relished going after increasingly exotic targets: galaxy clusters, quasars, carbon stars, and what have you. But we shouldn’t forget that most sky observers have modest telescopes and many are getting their first views of distant objects beyond the solar system. Astro enthusiast David Fuller’s story on page 40 highlights some of the brightest…

astro letters

A special device I want to say how much I enjoyed Raymond Shubinski’s article on the Antikythera Mechanism (March 2021); it is a truly remarkable device. My interest stems from the fact I gave a PowerPoint presentation on the mechanism to the members of my club — Ford Amateur Astronomy Club — last May. Since giving my talk, I keep checking in online with the Antikythera Mechanism Research Project for more news. — Don Klaser, Center Line, MI To the end of the universe I must compliment you on the January 2021 special issue about the beginning, the middle, and the end of the universe. Having the entire history explained over several well-chosen topics, each of which have a succinct two- to three-page explanation, was a delight to read. Each story had the…

strands of the cosmic web revealed

A giant web of invisible gas weaves throughout the universe, providing the scaffolding out of which galaxies are constructed. For decades, computer simulations have predicted the structure of this cosmic web. But until now, the only way to see it was indirectly, in a few select regions backlit by quasars — galaxies with bright, blazing cores. In March, sophisticated instruments captured light emitted directly by the cool hydrogen gas filaments of the cosmic web. For 140 hours, astronomers focused the European Southern Observatory’s Very Large Telescope (VLT) on a section of the Hubble Ultra Deep Field — the deepest view of the universe ever taken, which forms the background of this composite image. Using the VLT’s Multi Unit Spectroscopic Explorer, or MUSE, the team was able to image cosmic filaments from…

hot bytes

TURN IT DOWN Seen as it existed just 780 million years after the Big Bang, the quasar P172+18 is the oldest example yet found of a radio-loud quasar — a galaxy with an actively feeding supermassive black hole with jets emitting intense radio waves. GONE TO GROUND New research suggests that up to 99 percent of the water in the oceans that once covered Mars may be locked in minerals buried within the planet’s crust. This challenges previous assumptions that most of Mars’ water evaporated and escaped into space. ONE STEP CLOSER The core stage of NASA’s Space Launch System rocket performed a test firing lasting eight minutes and 19 seconds, a key development milestone. The test simulated the rocket’s planned launches of Moonbound Artemis missions later this decade.…

event horizon telescope maps a black hole’s magnetic field

Deep inside the elliptical galaxy M87 lurks a supermassive black hole with 6.5 billion times the mass of our Sun. In April 2019, this black hole became the first to have its shadow directly imaged, thanks to the Event Horizon Telescope (EHT) collaboration. On March 24, 2021, the same collaboration released updated views of M87 that reveal a complex magnetic field around the black hole; astronomers believe the field could power the black hole’s 5,000-light-year-long jet. The images accompany two papers published the same day in The Astrophysical Journal Letters, while a third related study has also been accepted for publication in The Astrophysical Journal Letters. GETTING ORIENTED When light passes near a strong magnetic field, its tug leaves an unmistakable mark. Like iron filings that align themselves and reveal the invisible magnetic…

a born-again star

Revivals don’t just happen in tents. They can also happen in deep space — like at the heart of Abell 78, an unusual planetary nebula imaged here by the Hubble Space Telescope and the Pan-STARRS telescope in Hawaii. Located about 5,000 light-years away in the constellation Cygnus, this sight was produced by a star that, in its death throes, blew its outer layers of gas into space. Most stars of similar mass settle into their graves quietly, producing no further nuclear reactions. But Abell 78 accumulated enough material in its outer layers to reignite nuclear fusion, triggering a second outburst that plowed into the initial halo, shocking it and creating the nebula’s bright, complex inner structure. Abell 78 is one of only a handful of known so-called “born-again planetary nebulae.” ESA/HUBBLE…