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Science
Australian Sky & Telescope

Australian Sky & Telescope

November - December 2020

Australian Sky & Telescope is a world-class magazine about the science and hobby of astronomy.  Combining the formidable worldwide resources of its venerable parent magazine with the talents of the best science writers and photographers in Australia, Australian Sky & Telescope is a magazine produced specifically for the Southern Hemisphere’s astronomers.

Country:
Australia
Language:
English
Publisher:
Paragon Media Pty Ltd
Frequency:
Bimonthly
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6 Issues

in this issue

1 min.
astronomy – not a nerdy pursuit

I FIND IT HARD TO UNDERSTAND those people who think astronomy is a waste of time, or some kind of pursuit that only nerds enjoy. They don’t seem to realise that relishing the night sky is just as valid as going on a bushwalk or a visit to the beach, or diving on the Great Barrier Reef. It’s all part of exploring the natural world, and the cosmos is the natural world on the grandest scale. Who can look at a photo of a nebula or a galaxy and not be awestruck by the majesty of space? Witness the winning images from this year’s David Malin Awards (see page 14) — simply amazing. As the judge and namesake of the awards, David Malin, has remarked, the kinds of images we’re seeing…

2 min.
no signs of life in vela…

NO RADIO SIGNALS HAVE BEEN detected during a deep search for low-frequency transmissions emanating from a region in the direction of the southern constellation Vela. The volume of space covered by the survey — conducted with the Murchison Widefield Array (MWA) in Western Australia — is known to contain at least 10 million stars. The study was run by CSIRO astronomer Dr Chenoa Tremblay and Professor Steven Tingay, Deputy Executive Director of the International Centre for Radio Astronomy Research (ICRAR) and leader the Curtin University node of ICRAR. The MWA was employed to listen for radio signals at wavelengths similar to those used by FM radio stations. Any such signals would be suggestive of a non-natural source, or what astronomers call ‘technosignatures’. “The MWA is a unique telescope, with an extraordinarily wide field-of-view that…

3 min.
.. but signs of life on venus?

A TEAM OF RESEARCHERS LED by Jane Greaves (Cardiff University, UK) has announced the detection of phosphine in the cool cloud decks of Venus. Phosphine is a trace gas in Earth’s atmosphere associated with anaerobic life. Astronomers have previously observed it on Jupiter and Saturn, but its production there is understood to be driven by the gas giants’ high pressure, hydrogen-rich environments and intensely hot depths. On Venus, it could be a sign of something else entirely. Greaves and her colleagues observed Venus first with the James Clark Maxwell Telescope (JCMT) in 2017, then again with the Atacama Large Millimeter/submillimeter Array (ALMA) in 2019. They observed the planet at millimetre wavelengths and found the chemical fingerprint of phosphine — a molecule that many think could be a biosignature, or sign of life. The…

3 min.
jupiter might have 600 moons

JUPITER COULD HAVE around 600 moons measuring at least 800 metres in diameter, according to a team of Canadian astronomers. Most of the moons are in wide, irregular and retrograde orbits. Over the past 20 years, astronomers have found dozens of small Jovian moons thanks to technological advances with large digital cameras. Back in 2003, Scott Sheppard (Carnegie Institution of Science) had already estimated that the number of irregular moons larger than a kilometre would probably be around 100. Now, Edward Ashton, Matthew Beaudoin and Brett Gladman (University of British Columbia, Vancouver) have detected about four dozen possible new Jovian moons that are even smaller. Extrapolating from the sky area they have searched (about one square degree), they conclude that there could be some 600 of these tiny objects orbiting the giant…

1 min.
astronomers find sn 1987a’s neutron star

SUPERNOVA 1987A WAS one of the most-observed supernovae in history after it exploded in the Large Magellanic Cloud just 168,000 light-years away. Telescopes around the globe and in space captured the blast wave, which illuminated three overlapping rings of material that had likely blown off in the star’s final years. But in the 33 years since, a puzzle has plagued astronomers. Neutrinos received at Earth right after the supernova indicated that the collapsed object ought to be a neutron star. But astronomers couldn’t find it. Dust obscures the centre of the blast, and some even wondered if the core had collapsed further into a black hole. Closer study showed the gaseous remains of the star’s outer layers to be slightly off-kilter, hinting that whatever compact object had formed in the blast had…

1 min.
close encounters in the milky way’s bulge

NEW RESEARCH SHOWS that stellar flybys are common in our galaxy’s crowded centre. Visits from interlopers could affect how young worlds grow in the Milky Way’s bulge. Moiya McTier (Columbia University) and colleagues conducted simulations of interactions between bulge stars over time. They found that over a billion-year period, roughly 80% of bulge stars would experience close encounters, passing within 1,000 astronomical units (a.u.) of another star. Half of bulge stars would have such an encounter not just once but more than 35 times over the course of a billion years. About a third of bulge stars could have company swing by within 100 a.u., and less than 1 in 5,000 stars entertain a visitor within 10 a.u. The new study takes into account both the crowded environs at the galactic centre…