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March 2020: Kaboom

March 2020

In the show this time, we talk to Rebecca Bowler about galaxies in the early universe, Alice Humpage rounds up the latest news, and we find out what we can see in the March night sky from Ian Morison, Haritina Mogosanu and Samuel Leske.

The News

In the news this Month: Telescopes detect the biggest explosion since the big bang in the Ophiuchus Supercluster, the Insight lander detects 174 Marsquakes, and a second planet is found around our closest star, Proxima Centauri.

First, a massive explosion from the Ophiuchus Galaxy, 390 million light-years away has been detected. This is the biggest eruption in the observable universe since the Big Bang, five times as large as the previous record holder. It was caused by a jet of radio emission shooting from a supermassive black hole. The first signs of the explosion came in 2016, when the supercluster was found to have a curved edge. This was possibly the wall of a cavity created by jets of hot gas being expelled from the black hole, but the evidence at the time wasn’t enough to confirm what was a very extreme result.

Those first observations were made with the Chandra X-ray telescope, but a combination of different telescopes were required to find out more about the strange galaxy. These latest results were made by using the previous Chandra data, archive data from the giant metre wave telescope, as well as new observations with the XMM-Newton to confirm the previous observations, and further observations in the radio with the Murchison wide field array.

This combination confirmed the previous theories of a cavity caused by a supermassive jet, since the radio data showed the curved wall is bordering an area filled with radio emission, as a result of electrons moving nearly the speed of light.

Next, NASA’s Insight lander has detected Marsquakes , proving that Mars has significant seismic activity. Insight has detected 174 of these marsquakes, multiple of magnitude 3 or 4, which is large enough to be felt by humans.

The Insight landed on the red planet on the 26th November, 2018, in the area called Elysium Planitia. Its main goal is to better understand the internal and thermal structure, and the composition of Mars.

The magnitude 3 and 4 quakes were strong enough to allow their origins to be traced back to an area called Cerberus Fossae, about 1000 miles away. This region has faults, volcanic flows, and liquid water channels.

The seismic activity on Mars is not the same as it is on Earth, since there are no tectonic plates. However, there will be cooling and contraction from the magma beneath the surface. Therefore, the activity is more like what we see away from the tectonic plate boundaries, like in the UK.

Detecting seismic events tells us more than whether the interior of Mars is active, it will also tell us about the interior of the planet, based on how the waves propagate, and about the atmosphere, with the detection of the magnetic field on Mars.

Finally, a second planet has been found orbiting our closest star , Proxima Centauri. The newly discovered Proxima c is a super-earth, a planet which is more massive than the Earth, but less massive than the ice giants. It was detected by the radial velocity method, where changes in the position of the star are measured to look for the gravitational impact of planets.

Even though it is our closest star, at 4.2 light years away, it would still take tens of thousands of years to reach with current rockets. However the discovery is significant for planet formation models, because it seems to have formed further away from the star than expected for a super-Earth.

Interview with Rebecca Bowler

Dr Rebecca Bowler talks about her work studying galaxy formation in the early universe. She discusses what we currently know about these galaxies and the advantages of using the Hubble space telescope to image them. She then discusses observing dust in these galaxies with ALMA. (the Atacama Large Millimetre Array), as well as comparing our knowledge with simulations of galaxy formation. The interview closes with a discussion of future observations, in particular the JWST (James Webb Space Telescope) and why it will be helpful for the study of early galaxies.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during March 2020.

The Planets

Southern Hemisphere

Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during March 2020.

Did you know that Venus is in the night sky this time of the year but if you are a morning owl, you can see Mars, Jupiter and Saturn in the morning sky? They are joined by Mercury later in the month.

Great objects to look at are the stars between Orion and the Southern Cross.

Around 8-9 PM Sirius and Canopus reach the meridian almost at the same time, and they are quite a sight! Sirius is north of the meridian and Canopus is south. They are followed closely by the Milky Way, that now looks like an octopus leg arching across the sky from behind the horizon and reaching Zenith at about 10PM.Scorpius is not yet visible unless you wait until the early hours of the morning.

The equinox falls on a Friday, Friday the 20th of March just as people finish work, at around 4:49 PM just in time for the weekend. The Pleiades, that is the famous starcluster whose heliacal rising marks the Maori New Year in New Zealand is now called Te Tawiti, and part of the grand asterism of the birdcatcher is preparing to disappear behind the Sun for the next two months.

The Magellanic clouds, our neigbouring galaxies are in a good position to observe, and in all this beautiful sky are some amazing deep sky objects to see. Here is what you need to do. Look for Venus just after sunset on the Western horizon, it will be high and bright in the sky, visible with the naked eye, binoculars and through the telescopes.

Next visible after Venus will be the three brightest stars in the sky, Sirius -- look up to see it it’s a bit north of overhead - so it is the dogstar that we are looking for, and look for Canopus a bit south of overhead, and that’s what we call here the cat star. Then turn South, there you will see Alpha Centauri the third brightest star in the sky.By this time it would be dark enough to start seeing the patches of stars that make the Milky Way and that should happen around 9PM. Mid month, by 9:30 is officially night, you should be able to see the Milky Way.

M45 the Pleiades, in binoculars is a lovely star cluster. On the other side of the sky, in Carina, the Southern Pleiades or Theta Carinae is the doppelgänger of the Pleiades. In Gemini we see the two brightest stars Castor (from NZ this is the closest to the horizon) and Pollux. The constellation has also a neutron star (Geminga) and a few deep sky objects: the open cluster Messier 35, the Eskimo Nebula, the Jellyfish Nebula and Medusa Nebula.

Castor and Pollux have been associated in antiquity with the appearance of two St Elmo’s fires. M 44 - the Praesepes cluster - this is a good object for binoculars and not so much for telescopes, it’s also known as the beehive cluster. On the opposite part of the sky, we will look at the Southern Beehive.

In Leo, we have the Leo triplet of M66, M65 and NGC 3628. The star Wolf 359 (CN Leonis), one of the nearest stars to Earth at 7.8 light-years away, is also in Leo. Wolf 359 is a red dwarf of magnitude 13.5; it periodically brightens by one magnitude or less because it is a flare star. It is also the solar system where the forces of the United Federation of Planets and the Borg Collective had the most destructive battles in the history of the Federation in 2367.Other Messier objects in Leo are Messier 95, Messier 96 and M 105

Moving along the Milky Way, we have M42 in Orion - great object no matter when, one of the first deep sky objects to be visible just after sunset.

In Canis Major, is M41 Just underneath the Big Dog, in Puppis M 46 is a beautiful open cluster that has a planetary nebula. And M68, a globular cluster in Hydra. And then all the beautiful objects of Vela and Carina and Centaurus and everything else on the south celestial region.

We observed Omega Centauri, the largest globular cluster in the sky, in Centaurus. Also in Centaurus, NGC4945, a spiral galaxy, NGC 4976 an elliptical galaxy, just below that in Lupus we looked at a planetary nebula, IC4406, then we saw NGC 5460, an open cluster in Centaurus, NGC 5286, a globular cluster also in Centaurus, the beautiful NGC 3918 the Blue Planetary Nebula and then in Carina NGC 3532 an open cluster in Carina, the Jewel box cluster, NGC4755 in Crux, the Gem Cluster NGC3293 open cluster in Carina, the Eta Carinae nebula - NGC 3372, Alpha Centauri - or Rigil Kentaurus, the double star our closest neighbour, NGC 3114 open cluster in Carina, NGC 2867 - planetary nebula in Carina, NGC 4833 globular cluster in Musca, Wray 16-41 planetary nebula in Carina, NGC 4372 - globular cluster in Musca, NGC2019 globular cluster in Mensa, NGC2100 globular cluster in Dorado, home of the Large Magellanic Cloud and NGC 2070 Tarantula Nebula - we look at this one all the time because we can. Then a series of open clusters in Dorado: NGC 2109, 2096, 2098, 1910, 1917, 1856, 1858, 1855 and 1850.

From New Zealand we wish you clear skies!

Odds and Ends

One consequence of becoming a published author is being targeted by predatory journals and conferences, which can sometimes be unintentionally hilarious. Jake shares a couple of gems which got past the spam filters. On a far more serious note, a paper has recently appeared on the arXiv detailing the issues that ground-based astronomy will face if planned megaconstellations of satellites go ahead. With anything up to 50,000 new objects in various Earth orbits planned, both optical and radio observations could become polluted, with the paper’s authors even considering legal action through international courts to temporarily halt further satellite launches. A second study accepted to A&A finds that narrow-field optical observations will be less affected, but wide-field surveys such as those planned for the Vera C. Rubin Telescope will be severely impacted, with anything up to 50% of exposures damaged by satellite trails.

Betelgeuse has been experiencing an unprecedented level of dimming over the last few months, the cause for which is still not certain. Recently, it has begun to brighten again. We discuss what's happening and float ideas about some possible causes

Recently, Kacper Wierzchos and Teddy Pruyne at the Catalina Sky Survey discovered that the Earth has acquired a new mini-moon. On February 15th, they spotted a 20th magnitude object orbiting us, which has been named 2020 CD3, and is the second mini-moon to have been spotted after 2006 RH120 in 2009, discovered by the same survey. 2020 CD3 is believed to be between 1.9 and 3.5 metres across, with a likely mass of about 5000kg - about the size and weight of a larger car. Studies of its orbit have found that it’s likely been there for between one and three years, but wasn’t previously observed as it’s very small – see here for of a gif of its orbit, with the Moon’s orbit shown in white for reference. Our new mini-moon isn’t expected to be a long-term presence, however - as its orbit isn’t stable, it’s estimated that it’ll escape the Earth’s gravitational pull and return to space within the next year.

Show Credits

News:Alice Humpage
Interview:Rebecca Bowler and Michael Wright
Night sky:Ian Morison and Haritina Mogosanu
Presenters:Fiona Porter, Mariam Rashid and Jake Staberg Morgan
Editors:Lizzy Lee, Joseph Winnicki, Tom Scragg and Haritina Mogusanu
Segment Voice:Tess Jaffe
Website:Michael Wright and Stuart Lowe
Producer:Michael Wright
Cover art:Data combined from the Chandra X-ray telescope, XMM Newton, the Murchison wide field array and the giant metrewave telescope providing evidence for the explosion in the Ophiucus cluster. CREDIT: X-ray: Chandra: NASA/CXC/NRL/S. Giacintucci, et al., XMM-Newton: ESA/XMM-Newton; Radio: NCRA/TIFR/GMRT; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF

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