Australian Sky & Telescope

Australian Sky & Telescope July 2019

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.

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1 minutos
remembering tranquility base

FOR THOSE OF US of a certain age, it’s sort of hard to believe that 50 years have passed since Neil Armstrong uttered those famous words: “That’s one small step for [a] man… one giant leap for mankind”. Yet half a century has indeed come and gone. And crewed spaceflight beyond Earth orbit seems to have come and gone too. No-one has travelled further than 620 kilometres from Earth’s surface since 1997, when the space shuttle Discovery boosted the Hubble Space Telescope to a higher orbit. Why haven’t we been back to the Moon? Politics and money, essentially. The ‘space race’ is long gone, and there is little political will for expensive Moon ventures. That said, there has been something of a resurgence in lunar exploration in recent years, with US,…

5 minutos
scientists unveil first black hole image

SCIENTISTS HAVE AT LAST ‘seen’ a black hole — and it’s beautiful. Announcing the result at a National Science Foundation press conference in Washington, D.C., representatives of the Event Horizon Telescope (EHT) collaboration unveiled a reconstructed image of the gargantuan black hole in the giant elliptical galaxy M87. The galaxy lies about 55 million light-years away in the constellation Virgo. The black hole itself is so large that light would take 1½ days to cross it. “We have seen what we thought was unseeable,” said project director Sheperd Doeleman (Center for Astrophysics, Harvard & Smithsonian) during the press conference. “We have seen and taken a picture of a black hole. Here it is.” Capturing a black hole’s visage requires far more than just a point-and-shoot approach. The worldwide team of researchers, comprising…

2 minutos
is there methane on mars?

TWO STUDIES ARE FINDING conflicting results about whether methane exists on Mars. Its presence would point to certain geochemical processes or, less likely, biological activity. Researchers using the Planetary Fourier Spectrometer (PFS) aboard Europe’s Mars Express orbiter spotted 15.5 parts per billion by volume (ppbv) of methane in 2013, a day after NASA’s Curiosity rover measured a spike of 5.78 ppbv. Atmospheric simulations and geological analysis helped track the emission’s origin to a fault area southeast of Gale Crater, Marco Giuranna (National Institute of Astrophysics, Italy) and colleagues report April 1 in Nature Geoscience. However, the European-Russian ExoMars Trace Gas Orbiter (TGO), a spacecraft designed to measure vanishingly small amounts of gases in the carbon dioxide–based atmosphere, has failed to find any methane during the first months of its science operations. The…

1 minutos
in brief

2020 NASA budget boosts exploration, not science The US president’s FY2020 budget request puts US$21.019 billion toward NASA — a drop of a half billion dollars from the just-approved 2019 budget. The proposal doubles funding for NASA’s return to the Moon via the Lunar Gateway, which aims to put a crewed outpost in lunar orbit. The budget request also initiates a Mars sample-return mission. At the same time, the proposal decreases funding for astrophysics (-20%), planetary science (-5%) and Earth science (-8%). And while the James Webb Space Telescope gains $46.6 million in funding, the Wide-Field Infrared Space Telescope (WFIRST) is cancelled. The request also zeroes out funding for NASA’s Office of STEM Engagement. However, the FY2019 budget request likewise cancelled WFIRST, STEM outreach and several Earth science missions, but instead…

3 minutos
ryugu vs. bennu: updates from the asteroids

SCIENTISTS WITH NASA’S Osiris-REX and the Japan Aerospace Exploration Agency’s Hayabusa 2 spacecraft provided preliminary results at the annual Lunar and Planetary Science Conference regarding their respective explorations of near-Earth asteroids 101955 Bennu and 162173 Ryugu. A slew of papers in Nature, Nature Astronomy, Nature Geoscience and Science accompanied the presentations. Except for size, Bennu and Ryugu are hard to tell apart in photos. Both are so-called ‘rubble piles,’ collections of debris weakly bound by gravity. Their low densities imply Swiss-cheese interiors. On the surface, both terrains are dark (reflecting about 4.5% of incident sunlight) and strewn with large boulders. And, despite being around for more than 100 million years, both bodies have few small craters, suggesting that something — perhaps shaking from bigger impacts — is filling them in. Because of…

2 minutos
two galaxies are missing their dark matter

ASTRONOMERS HAVE DISCOVERED a second galaxy without dark matter. This ultra-diffuse galaxy is one of thousands of large, star-poor objects discovered in recent years. Most of these galaxies have more than the usual amount of dark matter — it’s all that keeps their sparse stars from disbanding. But last year, Pieter van Dokkum (Yale) and colleagues discovered one without much dark matter at all, dubbed NGC 1052-DF2. Now the team has discovered a second one in the same region, suggesting more might be present. Van Dokkum and colleagues found NGC 1052-DF4 in images taken with the lenses of the Dragonfly Telephoto Array. They followed up with Hubble Space Telescope imaging and spectroscopy through the Keck I telescope on Mauna Kea, Hawai‘i. The observations appear in the March 20 issue of Astrophysical Journal…