Universe Today

December 12, 2019December 12, 2019 by Susie Murph

Carnival of Space #641

Carnival of Space. Image by Jason Major.

This week’s Carnival of Space is hosted by me at the CosmoQuest blog.

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December 12, 2019December 12, 2019 by Evan Gough

How Spiral Galaxies Get Their Shape

Magnetic fields in NGC 1086, or M77, are shown as streamlines over a visible light and X-ray composite image of the galaxy from the Hubble Space Telescope, the Nuclear Spectroscopic Array, and the Sloan Digital Sky Survey. The magnetic fields align along the entire length of the massive spiral arms — 24,000 light years across (0.8 kiloparsecs) — implying that the gravitational forces that created the galaxy’s shape are also compressing the its magnetic field. This supports the leading theory of how the spiral arms are forced into their iconic shape known as “density wave theory.” SOFIA studied the galaxy using far-infrared light (89 microns) to reveal facets of its magnetic fields that previous observations using visible and radio telescopes could not detect. Credits: NASA/SOFIA; NASA/JPL-Caltech/Roma Tre Univ.

Spiral galaxies are an iconic form. They’re used in product logos and all sorts of other places. We even live in one. And though it may seem kind of obvious how they get their shape, by rotating, that’s not the case.

December 11, 2019December 11, 2019 by Evan Gough

Wow, Meade Instruments Just Filed for Bankruptcy Protection

Meade Instruments, a company familiar to any backyard astronomer who’s drooled over their telescopes, has filed for bankruptcy. The company has fallen on hard times in recent years, as they’ve faced increasing competition. Meade also recently lost a lawsuit, which pushed them over the edge into bankruptcy.

The company is based in Irvine, California, and was founded in 1972. They started out selling small refracting telescopes. They expanded into Newtonian reflectors and Schmidt-Cassegrain telescopes over the years. Now, they sell telescope models worth upwards of $10,000.

December 11, 2019December 15, 2019 by Matt Williams

This Galaxy Has Been Home to 5 Supernovae in the Last 20 Years

Some of the most dramatic events in the Universe occur when certain stars die — and explode catastrophically in the process. Such explosions, known as supernovae, mainly occur in a couple of ways: either a massive star depletes its fuel at the end of its life, become dynamically unstable and unable to support its bulk, collapses inwards, and then violently explodes; or a white dwarf in an orbiting stellar couple syphons more mass off its companion than it is able to support, igniting runaway nuclear fusion in its core and beginning the supernova process. Both types result in an intensely bright object in the sky that can rival the light of a whole galaxy. In the last 20 years the galaxy NGC 5468, visible in this image, has hosted a number of observed supernovae of both the aforementioned types: SN 1999cp, SN 2002cr, SN2002ed, SN2005P, and SN2018dfg. Despite being just over 130 million light-years away, the orientation of the galaxy with respect to us makes it easier to spot these new ‘stars’ as they appear; we see NGC 5468 face on, meaning we can see the galaxy’s loose, open spiral pattern in beautiful detail in images such as this one from the NASA/ESA Hubble Space Telescope.

When stars die, they don’t die quietly but prefer to go out with a bang! This is known as a supernova, which occurs when a star has expended all of its fuel and undergoes gravitational collapse. In the process, the outer layers of the star will be blown off in a massive explosion visible from billions of light-years away. For decades, NASA has been monitoring galaxies beyond the Milky Way and detected numerous supernova taking place.

For instance, over the past 20 years, the Hubble Space Telescope has been monitoring the galaxy NGC 5468 – an intermediate spiral galaxy located roughly 130 million light-years from Earth in the constellation Virgo. In that time, this galaxy has experienced 5 supernovae and, thanks to its orientation (perpendicular to our own), astronomers have been able to study this galaxy and its supernovae in glorious detail.

December 11, 2019December 11, 2019 by Evan Gough

We Know We’re Made of Stardust. But Did it Come From Red Giants?

Artist's impression of a red giant star. If the star is in a binary pair, what happens to its sibling? Credit:NASA/ Walt Feimer

We’ve all heard this one: when you drink a glass of water, that water has already been through a bunch of other people’s digestive tracts. Maybe Attila the Hun’s or Vlad the Impaler’s; maybe even a Tyrannosaurus Rex’s.

Well, the same thing is true of stars and matter. All the matter we see around us here on Earth, even our own bodies, has gone through at least one cycle of stellar birth and death, maybe more. But which type of star?

That’s what a team of researchers at ETH Zurich (Ecole polytechnique federale de Zurich) wanted to know.

December 11, 2019January 1, 2020 by Susie Murph

Weekly Space Hangout: December 11, 2019 – Charlie Duke and Tom O’Conner from Astrograms

Hosts: Fraser Cain (universetoday.com / @fcain)

Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)

Dave Dickinson (www.astroguyz.com / @astroguyz)

Carolyn Collins Petersen (TheSpaceWriter.com / @spacewriter)

Moiya McTier (https://www.moiyamctier.com/ / @GoAstroMo)

December 10, 2019December 12, 2019 by Matt Williams

Why Does Enceladus Have Stripes at its South Pole?

Scientists recently determined that a certain strain of Earth bacteria could thrive under conditions found on Enceladus. Credit: NASA/JPL/Space Science Institute

Saturn’s moon Enceladus has captivating scientists ever since the Voyager 2 mission passed through the system in 1981. The mystery has only deepened since the arrival of the Cassini probe in 2004, which included the discovery of four parallel, linear fissures around the southern polar region. These features were nicknamed “Tiger Stripes” because of their appearance and the way they stand out from the rest of the surface.

Since their discovery, scientists have attempted to answer what these are and what created them in the first place. Thankfully, new research led by the Carnegie Institute of Science has revealed the physics governing these fissures. This includes how they are related to the moon’s plume activity, why they appear around Enceladus’ south pole, and why other bodies don’t have similar features.

December 10, 2019December 10, 2019 by Evan Gough

This is the Milky Way’s Magnetic Field

A representation of how our Galaxy would look in the sky if we could see magnetic fields. The plane of the Galaxy runs horizontally through the middle, and the Galactic centre direction is the middle of the map. Red–pink colours show increasing Galactic magnetic field strengths where the direction is pointing towards the Earth. Blue–purple colours show increasing Galactic magnetic field strengths where the direction is pointing away from the Earth. The background shows the signal reconstructed using sources outside our Galaxy. The points show the current measurements for pulsars. The squares show the measurements from this work using LOFAR pulsar observations. Image Credit: Sobey et al, 2019.

The Milky Way galaxy has its own magnetic field. It’s extremely weak compared to Earth’s; thousands of times weaker, in fact. But astronomers want to know more about it because of what it can tell us about star formation, cosmic rays, and a host of other astrophysical processes.

December 10, 2019December 10, 2019 by Evan Gough

NASA’s TESS Watched an Outburst from Comet 46P/Wirtanen

Comet 46P/Wirtanen. Image Credit: By Stub Mandrel at English Wikipedia, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=75160399

TESS, the Transiting Exoplanet Survey Satellite, has imaged an outburst from the comet 46P/Wirtanen. It caught the outburst in what NASA is calling the clearest images yet of a comet outburst from start to finish. A comet outburst is a significant but temporary increase in the comet’s activity, outside of the normal sunlight-driven vaporization of ices that creates a comet’s coma and tail.

Astronomers aren’t certain what causes them, but a new study based on this observation is shedding some light on them.

December 10, 2019December 10, 2019 by David Dickinson

December Meteor Squalls: Prospects for the 2019 Geminids and Ursids

December means chillier climes for northern hemisphere residents, a time to huddle inside near the campfire, both real and cyber. I’ve always thought this was a shame, as the cold crisp nights of winter also offer up sharp, clear skies. Over the past decade or so, December gives observers another reason to brave the cold: the Geminids.