Messier 84 – the NGC Elliptical Galaxy

This NASA/ESA Hubble Space Telescope image captures the galaxy Messier 84 — also known as NGC 4374 — an object from the Messier catalogue, published in its final version in 1781 by Charles Messier. This elliptical galaxy was discovered in March 1781 and lies about 60 million light-years away from Earth in the constellation of Virgo (The Virgin). The galaxy is part of the very heavily populated centre of the Virgo Cluster, a cluster which consists of more than 1000 galaxies. This image does not show the whole galaxy but only its very interesting centre, and is likely to be the best image of the region ever captured. Previous observations using Hubble’s Space Telescope Imaging Spectrograph (STIS) revealed a supermassive black hole in the centre of Messier 84. Astronomers found the supermassive black hole by mapping the motion of the gas and the stars which are caught in its grip. Next to its interesting centre Messier 84 is also known for its supernovae. Two supernovae have been observed within the galaxy. The first, SN1957 was discovered in 1957 and another, called SN1991bg, was discovered in 1991. Credit: NASA/ESA/HST

Welcome back to Messier Monday! Today, we continue in our tribute to our dear friend, Tammy Plotner, by looking at the elliptical (lenticular) galaxy known as Messier 84!

During the 18th century, famed French astronomer Charles Messier noticed the presence of several “nebulous objects”  while surveying the night sky. Originally mistaking these objects for comets, he began to catalog them so that others would not make the same mistake. Today, the resulting list (known as the Messier Catalog) includes over 100 objects and is one of the most influential catalogs of Deep Space Objects.

One of these objects is known as Messier 84, an elliptical (or lenticular) galaxy located about 54.9 million light years from Earth. This galaxy is situated in the inner core of the heavily populated Virgo Cluster and has two jets of matter shooting out of its center. It also has a rapidly rotating disk of gas and stars that are indicative of a supermassive black hole of 1.5 billion Solar masses at its center.

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Here’s the Video of Hayabusa2 Bombing Asteroid Ryugu

Artist's impression of the Hayabusa2 spacecraft touching down on the surface of the asteroid Ryugu. Credit: JAXA/Akihiro Ikeshita?

As part of its mission to explore the Near-Earth Asteroid (NEA)
162173 Ryugu, the Japan Aerospace Exploration Agency‘s (JAXA) Hayabusa2 spacecraft recently dropped a “bomb” on the asteroid’s surface. This explosive package, known as the Small Carry-on Impactor (SCI), was specifically designed to create a crater in the surface, thus exposing the interior for analysis.

The deployment of the SCI took place on April 5th, exactly six weeks after the spacecraft collected its first sample from the surface. Last Sunday, (April 21st, 2019), JAXA provided the video of the “bombing run” via the mission’s official twitter account. This was followed four days later by images of the crater that resulted, which revealed darker material from the interior that was now exposed to space.

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InSight Just Detected its First “Marsquake”

This artist's illustration of InSight on a photo background of Mars shows the lander fully deployed. The solar array is open, and in the foreground two of its instruments are shown. On the left is the SEIS instrument, and on the right is the HP3 probe. Image: NASA/Lockheed Martin

In November of 2018, the NASA Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander set down on Mars. Shortly thereafter, it began preparing for its science operations, which would consist of studying Mars’ seismology and its heat flow for the sake of learning how this planet – and all the other terrestrial planets in the Solar System (like Earth) – formed and evolved over time.

With science operations well-underway, InSight has been “listening” to Mars to see what it can learn about its interior structure and composition. A few weeks ago, mission controllers discovered that the lander’s Seismic Experiment for Interior Structure (SEIS) instrument detected its strongest seismic signal (aka. a “marsquake”) to date. This faint quake could reveal much about the Red Planet and how it came to be.

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As Expected, the Newly Upgraded LIGO is Finding a Black Hole Merger Every Week

In February 2016, LIGO detected gravity waves for the first time. As this artist's illustration depicts, the gravitational waves were created by merging black holes. The third detection just announced was also created when two black holes merged. Credit: LIGO/A. Simonnet.
Artist's impression of merging binary black holes. Credit: LIGO/A. Simonnet.

In February of 2016, scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO) announced the first-ever detection of gravitational waves (GWs). Since then, multiple events have been detected, providing insight into a cosmic phenomena that was predicted over a century ago by Einstein’s Theory of General Relativity.

A little over a year ago, LIGO was taken offline so that upgrades could be made to its instruments, which would allow for detections to take place “weekly or even more often.” After completing the upgrades on April 1st, the observatory went back online and performed as expected, detecting two probable gravitational wave events in the space of two weeks.

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Astronomers Catch a Superflare From a Puny Star

superflare
An artist's conception of a superflare event, on a dwarf star. Image credit: Mark Garlick/University of Warwick

You can be thankful that we orbit a placid, main sequence, yellow dwarf star. Astronomers recently spied a massive superflare on a diminutive star, a powerful, radiation spewing event that you wouldn’t want to witness up close.

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Weekly Space Hangout: Apr 24, 2019 – Nathaniel Putzig and Gareth Morgan of the Shallow Radar (SHARAD) Sounder Team on the Mars Reconnaissance Orbiter (MRO)

Hosts:
Fraser Cain (universetoday.com / @fcain)
Dr. Pamela Gay (astronomycast.com / cosmoquest.org / @starstryder)
Dr. Kimberly Cartier (KimberlyCartier.org / @AstroKimCartier )
Dr. Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg & ChartYourWorld.org)
Dr. Paul M. Sutter (pmsutter.com / @PaulMattSutter)

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Astronomers Think a Meteor Came from Outside the Solar System

Multi-photo composite showing Perseid meteors shooting from their radiant point in the constellation Perseus. Earth crosses the orbit of comet 109P/Swift-Tuttle every year in mid-August. Debris left behind by the comet burns up as meteors when it strikes our upper atmosphere at 130,000 mph. Credit: NASA

When ‘Oumuamua was first detected on October 19th, 2017, astronomers were understandably confused about the nature of this strange object. Initially thought to be an interstellar comet, it was then designated as an interstellar asteroid. But when it picked up velocity as it departed our Solar System (a very comet-like thing to do), scientists could only scratch their heads and wonder.

After much consideration, Shmuel Bialy and Professor Abraham Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA) proposed that ‘Oumuamua could in fact be an artificial object (possibly an alien probe). In a more recent study, Amir Siraj and Prof. Loeb identified another (and much smaller) potential interstellar object, which they claim could be regularly colliding with Earth.

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Barfing Neutron Stars Reveal Their Inner Guts

Artist's illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling spacetime grid indicates the isotropic gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet

We don’t really understand neutron stars. Oh, we know that they are – they’re the leftover remnants of some of the most massive stars in the universe – but revealing their inner workings is a little bit tricky, because the physics keeping them alive is only poorly understood.

But every once in a while two neutron stars smash together, and when they do they tend to blow up, spewing their quantum guts all over space. Depending on the internal structure and composition of the neutron stars, the “ejecta” (the polite scientific term for astronomical projectile vomit) will look different to us Earth-bound observers, giving us a gross but potentially powerful way to understand these exotic creatures.

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You Could Travel Through a Wormhole, but it’s Slower Than Going Through Space

Artist illustration of a spacecraft passing through a wormhole to a distant galaxy. Image credit: NASA.
Artist illustration of a spacecraft passing through a wormhole to a distant galaxy. Image credit: NASA.

Special Relativity. It’s been the bane of space explorers, futurists and science fiction authors since Albert Einstein first proposed it in 1905. For those of us who dream of humans one-day becoming an interstellar species, this scientific fact is like a wet blanket. Luckily, there are a few theoretical concepts that have been proposed that indicate that Faster-Than-Light (FTL) travel might still be possible someday.

A popular example is the idea of a wormhole: a speculative structure that links two distant points in space time that would enable interstellar space travel. Recently, a team of Ivy League scientists conducted a study that indicated how “traversable wormholes” could actually be a reality. The bad news is that their results indicate that these wormholes aren’t exactly shortcuts, and could be the cosmic equivalent of “taking the long way”!

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