Thursday, March 15, 2018

Across The Universe - In the Heart of the Heart Nebula

In the Heart of the Heart Nebula:

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Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 February 14




See Explanation.  Clicking on the picture will download  the highest resolution version available.
Explanation:
What's that inside the Heart Nebula?

First, the large emission nebula dubbed
IC 1805 looks, in whole, like a human heart.

It's shape perhaps fitting of the
Valentine's Day,
this heart glows brightly in red light
emitted by its most prominent element:
hydrogen.

The red glow and the larger shape are all created by a
small group of stars near the
nebula's center.

In the heart of the
Heart
Nebula are young stars from the open star cluster
Melotte 15 that are eroding away several picturesque
dust pillars with their energetic light and winds.

The open cluster of stars contains a few
bright stars nearly 50 times the mass of our Sun,
many dim stars only a fraction of the mass of our Sun, and an
absent microquasar
that was expelled millions of years ago.

The Heart Nebula is located about 7,500 light years away toward the
constellation
of the mythological Queen of Aethiopia (Cassiopeia).


Across The Universe - Jupiter in Infrared from Hubble

Jupiter in Infrared from Hubble:

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2018 February 21




See Explanation.  Clicking on the picture will download  the highest resolution version available.


Jupiter in Infrared from Hubble

Image Credit:
NASA,
ESA,
Hubble;
Data:
Michael Wong
(UC Berkeley)
et al.;
Processing &
License:

Judy Schmidt


Explanation:
Jupiter looks a bit different in infrared light.

To better understand
Jupiter's cloud motions and to help NASA's robotic
Juno spacecraft understand the
planetary context of the small fields that it sees, the
Hubble Space Telescope is being directed to
regularly image the entire Jovian giant.

The colors of Jupiter
being monitored go beyond the normal human visual range to include both
ultraviolet and
infrared light.

Featured here in 2016, three bands of near-infrared light have been digitally reassigned into a mapped color image.

Jupiter appears
different in infrared
partly because the amount of sunlight reflected back is distinct,
giving differing cloud heights and latitudes discrepant brightnesses.

Nevertheless, many familiar features on
Jupiter remain, including the
light zones and dark belts that circle the planet near the equator, the
Great Red Spot on the lower left, and the
string-of-pearls storm systems south of the Great Red Spot.

The poles glow because high altitude haze there is energized by charged
particles from Jupiter's
magnetosphere.

Juno has now completed
10 of 12 planned science orbits of Jupiter and continues to record data that are helping humanity to
understand not only Jupiter's weather but
what lies beneath Jupiter's thick clouds.




Tomorrow's picture: roses aren't red




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Across The Universe - When Roses Aren t Red

When Roses Aren t Red:

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2018 February 22




See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.


When Roses Aren't Red

Image Credit &
Copyright:


Eric Coles and
Mel Helm



Explanation:

Not all roses are red
of course,
but they can still be very pretty.

Likewise, the beautiful
Rosette
Nebula
and other star forming regions are often shown in
astronomical images with a predominately red hue,
in part because the dominant emission in the nebula is
from hydrogen atoms.

Hydrogen's strongest optical emission line, known as H-alpha,
is in the red region of the spectrum, but the beauty of an
emission nebula need not be appreciated
in red light alone.

Other
atoms
in the nebula are also excited by energetic
starlight and produce narrow emission lines as well.

In this gorgeous view of the Rosette Nebula,
narrowband images are combined to show
emission from sulfur atoms in red, hydrogen in blue, and
oxygen in green.

In fact, the
scheme of mapping these narrow atomic
emission lines into broader colors is adopted in
many Hubble images
of stellar nurseries.

The image spans about 100 light-years in
the constellation Monoceros, at the 3,000 light-year
estimated
distance of the
Rosette
Nebula
.

To make the Rosette red, just follow
this link or
slide your cursor over the image.



Tomorrow's picture: the moon isn't blue




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Across The Universe - Facing NGC 6946

Facing NGC 6946:

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2018 February 24




See Explanation.  Clicking on the picture will download  the highest resolution version available.


Facing NGC 6946

Composite Image Data -

Subaru Telescope
(NAOJ) and Robert Gendler;

Processing -

Robert Gendler



Explanation:

From our vantage point in the
Milky Way Galaxy, we see
NGC 6946
face-on
.

The big, beautiful
spiral galaxy
is located just 20 million light-years away, behind a veil of
foreground dust and stars in the high and far-off
constellation of Cepheus.

From the core outward, the galaxy's colors change from the yellowish
light of old stars in the center to young blue star
clusters and reddish star forming regions along the loose, fragmented
spiral arms.

NGC 6946 is also bright in
infrared light
and
rich in gas and dust, exhibiting a high star birth and
death rate.

In fact, since the early 20th century
ten
confirmed
supernovae, the
death explosions
of massive stars, were
discovered in NGC 6946.

Nearly 40,000 light-years across, NGC 6946 is also known as the
Fireworks Galaxy.

This remarkable portrait of NGC 6946
is a composite that includes
image
data from
the 8.2 meter Subaru Telescope
on Mauna Kea.



Tomorrow's picture: star fire




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Across The Universe - NGC 613 in Dust, Stars, and a Supernova

NGC 613 in Dust, Stars, and a Supernova:

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2018 February 28




See Explanation.  Clicking on the picture will download  the highest resolution version available.


NGC 613 in Dust, Stars, and a Supernova

Image Credit:
NASA,
ESA,
Hubble,
S. Smartt
(QUB);
Acknowledgement:
Robert Gendler;
Insets: Victor Buso


Explanation:
Where did that spot come from?

Amateur astronomer Victor Buso was testing out a new camera on his telescope in 2016 when he noticed a curious spot of light appear -- and remain.

After reporting
this unusual observation,
this spot was determined to be light from a
supernova
just as it was becoming visible -- in an earlier stage
than had ever been photographed optically before.

The discovery before and after images, taken about an hour apart,
are shown in the inset of a
more detailed image
of the same spiral galaxy,
NGC 613,
taken by the Hubble Space Telescope.

Follow-up observations show that
SN 2016gkg was likely the explosion of a
supergiant star,
and Buso likely captured the stage where the outgoing
detonation wave
from the stellar core
broke through
the star's surface.

Since astronomers have spent years
monitoring galaxies for supernovas without seeing such a "break out" event,
the odds of Buso capturing this
have been compared to
winning a lottery.




Tomorrow's picture: the lunar 15




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Across The Universe - Arcs, Jets, and Shocks near NGC 1999

Arcs, Jets, and Shocks near NGC 1999:

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Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional astronomer.


2018 March 7




See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.


Arcs, Jets, and Shocks near NGC 1999

Image Credit & Copyright:
Mark Hanson;
Annotation: Sakib Rasool
(StarSurfin)


Explanation:
This tantalizing array of nebulas and stars can be found
about two degrees south of the famous
star-forming Orion Nebula.

The
region abounds
with energetic young stars producing jets and
outflows that push through the surrounding
material at speeds of hundreds of kilometers per second.

The interaction creates luminous shock
waves known as
Herbig-Haro (HH) objects.

For example, the graceful, flowing arc just right of center
is cataloged as
HH 222, also called the
Waterfall Nebula.

Seen below the Waterfall, HH 401 has a distinctive cone shape.

The bright bluish nebula below and left of center
is NGC 1999, a dusty cloud reflecting
light from an embedded variable star.

The entire cosmic vista spans over 30 light-years, near the edge of the
Orion Molecular Cloud
Complex
some 1,500 light-years distant.




Open Science:
Browse 1,600+ codes in the Astrophysics Source Code Library

Tomorrow's picture: open space




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Across The Universe - Horsehead: A Wider View

Horsehead: A Wider View:

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2018 March 9




See Explanation.  Clicking on the picture will download  the highest resolution version available.


Horsehead: A Wider View

Composition and Processing:
Robert Gendler


Image Data:
ESO,
VISTA,
HLA,
Hubble Heritage Team (STScI/AURA)



Explanation:

Combined image data from the massive,
ground-based
VISTA telescope
and the
Hubble Space
Telescope
was used to create
this
wide perspective

of the interstellar landscape surrounding
the famous Horsehead Nebula.

Captured at near-infrared wavelengths, the region's dusty
molecular cloud sprawls across the scene that covers
an angle about
two-thirds the size of the Full Moon on the sky.

Left to right the frame spans just over 10 light-years
at the Horsehead's estimated distance of 1,600 light-years.

Also known as
Barnard 33,
the still
recognizable Horsehead Nebula
stands at the upper right,
the near-infrared glow of a dusty pillar topped with newborn stars.

Below and left, the bright reflection nebula NGC 2023 is itself
the illuminated environs of a hot young star.

Obscuring
clouds
below
the base of the Horsehead and on the outskirts of
NGC 2023 show the tell-tale far red emission of energetic jets,
known as Herbig-Haro objects,
also associated with newborn stars.



Tomorrow's picture: clair de lune




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Across The Universe - Dual Particle Beams in Herbig Haro 24

Dual Particle Beams in Herbig Haro 24:

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2018 March 11




See Explanation.  Clicking on the picture will download  the highest resolution version available.


Dual Particle Beams in Herbig-Haro 24

Image Credit:
NASA,
ESA,
Hubble Heritage
(STScI/AURA)/Hubble-Europe
Collaboration;

Acknowledgment:
D. Padgett (NASA's GSFC),
T. Megeath (U. Toledo),
B. Reipurth (U. Hawaii)


Explanation:
This might look like a double-bladed
lightsaber, but these two cosmic jets actually beam outward from
a
newborn star in a galaxy near you
.

Constructed from Hubble Space Telescope image data, the stunning
scene spans about half a light-year across
Herbig-Haro 24 (HH 24), some 1,300 light-years away in the
stellar nurseries
of the Orion B molecular cloud complex.

Hidden from direct view,
HH 24's
central protostar is
surrounded by cold dust and gas flattened into a rotating
accretion disk.

As material from the disk falls toward the young stellar object it heats up.

Opposing jets are blasted out along the
system's rotation axis.

Cutting through the region's interstellar matter, the narrow,
energetic jets produce a series of glowing shock fronts
along their path.




Tomorrow's picture: flying over earth




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Across The Universe - The Complete Galactic Plane: Up and Down

The Complete Galactic Plane: Up and Down:

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2018 March 13




See Explanation.  Clicking on the picture will download  the highest resolution version available.
Explanation:
Is it possible to capture the entire plane of our galaxy in a single image?

Yes, but not in one exposure -- and it took some planning to do it in two.

The top part of the
featured image is the night sky above
Lebanon,
north of the equator, taken in 2017 June.

The image was taken at a time when the central band of the
Milky Way Galaxy passed directly overhead.

The bottom half was similarly captured six months later in
latitude-opposite
Chile, south of
Earth's equator.

Each image therefore captured the night sky in
exactly the opposite direction of the other, when fully half the Galactic plane was visible.

The southern half was then inverted -- car and all -- and digitally
appended
to the top half to show the entire central
band of our Galaxy, as a circle, in a single image.

Many stars and nebulas are visible, with the
Large Magellanic Cloud
being particularly notable inside the lower half of the complete galactic circle.

Across The Universe - Interstellar Asteroid ‘Oumuamua Had a Violent Past

Interstellar Asteroid ‘Oumuamua Had a Violent Past:

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) telescope in Hawaii announced the first-ever detection of an interstellar asteroid – I/2017 U1 (aka. ‘Oumuamua). Originally mistaken for a comet, follow-up observations conducted by the European Southern Observatory (ESO) and others confirmed that ‘Oumuamua was actually a rocky body that had originated outside of our Solar System.

Since that time, multiple investigations have been conducted to determine ‘Oumuamua’s structure, composition, and just how common such visitors are. At the same time, a considerable amount of attention has been dedicated to determining the asteroid’s origins. According to a new study by a team of international researchers, this asteroid had a chaotic past that causes it to tumble around chaotically.

The study, titled “The tumbling rotational state of 1I/‘Oumuamua“, recently appeared in the scientific journal Nature Astronomy. The study was led by Wesley C. Fraser, a research fellow at the University of Queens Belfast’s Astrophysics Research Center, and included members from the Academy of Sciences of the Czech Republic, the The Open University and the University of Belgrade.



As they indicate, the discovery of ‘Oumuamua has provided scientists with the first opportunity to study a planetesimal born in another planetary system. In much the same way that research into Near-Earth Asteroids, Main Belt Asteroids, or Jupiter’s Trojans can teach astronomers about the history and evolution of our Solar System, the study of a ‘Oumuamua would provide hints as to what was going on when and where it formed.

For the sake of their study, Dr. Fraser and his international team of colleagues have been measuring ‘Oumuamua brightness since it was first discovered. What they found was that ‘Oumuamua wasn’t spinning periodically (like most small asteroids and planetesimals in our Solar System), but chaotically. What this means is that the asteroid has likely been tumbling through space for billions of years, an indication of a violent past.

While it is unclear why this is, Dr. Fraser and his colleagues suspect that it might be due to an impact. In other words, when ‘Oumuamua was thrown from its own system and into interstellar space, it is possible it collided violently with another rock. As Dr. Fraser explained in a Queen’s University Belfast press release:

“Our modelling of this body suggests the tumbling will last for many billions of years to hundreds of billions of years before internal stresses cause it to rotate normally again. While we don’t know the cause of the tumbling, we predict that it was most likely sent tumbling by an impact with another planetesimal in its system, before it was ejected into interstellar space.”


These latest findings mirror what other studies have been able to determine about ‘Oumuamua based on its object changes in its brightness. For example, brightness measurements conducted by the Institute for Astronomy in Hawaii – and using data from the ESO’s Very Large Telescope (VLT) – confirmed that the asteroid was indeed interstellar in origin, and that its shape is highly elongated (i.e. very long and thin).

However, measurements of its color have produced little up until now other than confusion. This was due to the fact that the color appeared to vary between measurements. When the long face of the object is facing telescopes on Earth, it appears largely red, while the rest of the body has appeared neutral in color (like dirty snow). Based on their analysis, Dr. Fraser and his team resolved this mystery by indicating that the surface is “spotty”.

In essence, most of the surface reflects neutrally, but one of its long faces has a large red region – indicating the presence of tholins on its long surface. A common feature of bodies in the outer Solar System, tholins are organic compounds (i.e. methane and ethane) that have turned a deep shade of reddish-brown thanks to their exposure to ultra-violet radiation.

What this indicates, according to Dr. Fraser, is broad compositional variations on ‘Oumuamua, which is unusual for such a small body:

“We now know that beyond its unusual elongated shape, this space cucumber had origins around another star, has had a violent past, and tumbles chaotically because of it. Our results are really helping to paint a more complete picture of this strange interstellar interloper. It is quite unusual compared to most asteroids and comets we see in our own solar system,” comments Dr Fraser.




Oumuamua as it appeared using the William Herschel Telescope on the night of October 29. Queen’s University Belfast/William Herschel Telescope
To break it down succinctly, ‘Oumuamua may have originated closer to its parent star (hence its rocky composition) and was booted out by strong resonances. In the course of leaving its system, it collided with another asteroid, which sent it tumbling towards interstellar space. It’s current chaotic spin and its unusual color are both testaments to this turbulent past, and indicate that its home system and the Solar System have a few things in common.

Since its arrival in our system, ‘Oumuamua has set off a flurry of scientific research. All over the world, astronomers are hoping to get a glimpse of it before it leaves our Solar System, and there are even those who hope to mount a robotic mission to rendezvous with it before its beyond our reach (Project Lyra). In any event, we can expect that this interstellar visitor will be the basis of scientific revelations for years to come!

This study is the third to be published by their team, which has been monitoring ‘Oumuamua since it was first observed in October. All studies were conducted with support provided by the Science and Technology Facilities Council.

Further Reading: Queen’s University Belfast

The post Interstellar Asteroid ‘Oumuamua Had a Violent Past appeared first on Universe Today.

Across The Universe - It Turns Out, Andromeda is Younger Than Earth… Sort Of

It Turns Out, Andromeda is Younger Than Earth… Sort Of:

Since ancient times, astronomers have looked up at the night sky and seen the Andromeda galaxy. As the closest galaxy to our own, scientists have been able to observe and scrutinize this giant spiral galaxy for millennia. By the 20th century, astronomers realized that Andromeda was the Milky Way’s sister galaxy and was moving towards us. In 4.5 billion years, it will even merge with our own to form a supergalaxy.

However, it seems astronomers were wrong about the Andromeda galaxy in one major respect. According to recent study led by a team of French and Chinese astronomers, this giant spiral galaxy formed from a major merger that occurred less than 3 billion years ago. This means that Andromeda, as we know it today, is effectively younger than our very own Solar System, which has it beat by about 1.5 billion years!

The study, titled “A 2-3 billion year old major merger paradigm for the Andromeda galaxy and its outskirts“, recently appeared in the Monthly Notices of the Royal Astronomical Society. Led by Francois Hammer, the Principle Investigator of the Galaxies, Etoiles, Physique et Instrumentation (GEPI) department at the Paris Observatory, the team included members from the Chinese Academy of Sciences and the University of Strasbourg.



For the sake of their study, the relied on data gathered by recent surveys that noted considerable differences between the Andromeda and Milky Way galaxies. The first of these studies, which took place between 2006 and 2014, demonstrated all Andromeda has a wealth of young blue stars in its disk (less than 2 billion years old) that undergo random motions over large scales. This is contrast to the stars in the Milky Way’s disk, which are subject only to simple rotation.

In addition, deep observations conducted between 2008 and 2014 with the French-Canadian telescope in the Hawaiian Islands (CFHT) indicated some interesting things about Andromeda’s halo. This vast region, which is 10 times the size of the galaxy itself, is populated by gigantic currents of stars. The most prominent of which is called the “Giant Stream”, a warped disk that has shells and clumps at its very edges.

Using this data, the French-Chinese collaboration then created a detailed numerical model of Andromeda using the two most powerful computers available in France – the Paris Observatory’s MesoPSL and the National Center for Scientific Research’s (CNRS) IDRIS-GENCI supercomputer. With the resulting numerical model, the team was able to demonstrate that these recent observations could be explained only by a recent collision.

Basically, they concluded that between 7 and 10 billion years ago, Andromeda consisted of  two galaxies that had slowly achieved a encountering orbit. After optimizing the trajectories of both galaxies, they determined that they would have collided 1.8 to 3 billion years ago. This collision is what gave birth to Andromeda as we know it today, which effectively makes it younger than our Solar System – which formed almost 4.6 billion years ago.



What’s more, they were able to calculate mass distributions for both parent galaxies that merged to formed Andromeda, which indicated that the larger galaxy was four times the size of the smaller. But most importantly, the team was able to reproduce in detail all the structures that compose Andromeda today – including the bulge, the bar, the huge disk, and the presence of young stars.

The presence of young blue stars in its disk, which has remained unexplained until now, is attributable to a period of intense star formation that took place after the collision. In addition, structures like the “Giant Stream” and the shells of the halo belonged to the smaller parent galaxy, whereas the diffuse clumps and the warped nature of the halo were derived from the larger one.

Their study also explains why the features attributed to the smaller galaxy have an under-abundance in heavy elements compared to the others – i.e. it was less massive so it formed fewer heavy elements and stars. This study is immensely significant when it comes to galactic formation and evolution, mainly because it is the first numerical simulation that has succeeded in reproducing a galaxy in such detail.

It is also of significance given that such a recent impact it could have left materials in the Local Group. In other words, this study could have implications that range far beyond our galactic neighborhood. It is also a good example of how increasingly sophisticated instruments are leading to more detailed observations which, when combined with increasingly sophisticated computers and algorithms, are leading to more detailed models.

One can only wonder if future extra-terrestrial intelligence (ETI) will draw similar conclusions about our own galaxy once it merges with Andromeda, billions of years from now. The collision and resulting features are sure to be of interest to anyone advanced species that’s around to study it!

Further Reading: Paris Observatory, Monthly Notices of the Royal Astronomical Society search and more info website

The post It Turns Out, Andromeda is Younger Than Earth… Sort Of appeared first on Universe Today.

Across The Universe - Neptune’s Huge Storm Is Shrinking Away In New Images From Hubble

Neptune’s Huge Storm Is Shrinking Away In New Images From Hubble:

Back in the late 1980’s, Voyager 2 was the first spacecraft to capture images of the giant storms in Neptune’s atmosphere. Before then, little was known about the deep winds cycling through Neptune’s atmosphere. But Hubble has been turning its sharp eye towards Neptune over the years to study these storms, and over the past couple of years, it’s watched one enormous storm petering out of existence.

“It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect.” – Michael H. Wong, University of California at Berkeley.
When we think of storms on the other planets in our Solar System, we automatically think of Jupiter. Jupiter’s Great Red Spot is a fixture in our Solar System, and has lasted 200 years or more. But the storms on Neptune are different: they’re transient.

Voyager 2 captured this image of Neptune in 1982, when it was over 7 million km (4.4 million miles) away from the planet. The Great Dark Spot in the middle of the image was the first storm ever seen on Neptune. Image: By NASA (JPL image) [Public domain], via Wikimedia Commons
The storm on Neptune moves in an anti-cyclonic direction, and if it were on Earth, it would span from Boston to Portugal. Neptune has a much deeper atmosphere than Earth—in fact it’s all atmosphere—and this storm brings up material from deep inside. This gives scientists a chance to study the depths of Neptune’s atmosphere without sending a spacecraft there.

The first question facing scientists is ‘What is the storm made of?’ The best candidate is a chemical called hydrogen sulfide (H2S). H2S is a toxic chemical that stinks like rotten eggs. But particles of H2S are not actually dark, they’re reflective. Joshua Tollefson from the University of California at Berkeley, explains: “The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere.”

“We have no evidence of how these vortices are formed or how fast they rotate.” – Agustín Sánchez-Lavega, University of the Basque Country in Spain.
But beyond guessing what chemical the spot might me made of, scientists don’t know much else. “We have no evidence of how these vortices are formed or how fast they rotate,” said Agustín Sánchez-Lavega from the University of the Basque Country in Spain. “It is most likely that they arise from an instability in the sheared eastward and westward winds.”

There’ve been predictions about how storms on Neptune should behave, based on work done in the past. The expectation was that storms like this would drift toward the equator, then break up in a burst of activity. But this dark storm is on its own path, and is defying expectations.

“We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.” – Michael H. Wong, University of California at Berkeley.
“It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect,” said Michael H. Wong of the University of California at Berkeley, referring to work by Ray LeBeau (now at St. Louis University) and Tim Dowling’s team at the University of Louisville. “Their dynamical simulations said that anticyclones under Neptune’s wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.”

Rather than going out in some kind of notable burst of activity, this storm is just fading away. And it’s also not drifting toward the equator as expected, but is making its way toward the south pole. Again, the inevitable comparison is with Jupiter’s Great Red Spot (GRS).

The GRS is held in place by the prominent storm bands in Jupiter’s atmosphere. And those bands move in alternating directions, constraining the movement of the GRS. Neptune doesn’t have those bands, so it’s thought that storms on Neptune would tend to drift to the equator, rather than toward the south pole.

Jupiter’s prominent storm, the Great Red Spot, is held in place by the alternating storm bands in Jupiter’s atmosphere. Image: By NASA, ESA, and A. Simon (Goddard Space Flight Center) [Public domain], via Wikimedia Commons
This isn’t the first time that Hubble has been keeping an eye on Neptune’s storms. The Space Telescope has also looked at storms on Neptune in 1994 and 1996. The video below tells the story of Hubble’s storm watching mission.



The images of Neptune’s storms are from the Hubble Outer Planets Atmosphere Legacy (OPAL) program. OPAL gathers long-term baseline images of the outer planets to help us understand the evolution and atmospheres of the gas giants. Images of Jupiter, Saturn, Uranus and Neptune are being taken with a variety of filters to form a kind of time-lapse database of atmospheric activity on the four gas planets.

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Across The Universe - Astronomers Observe the Rotating Accretion Disk Around the Supermassive Black Hole in M77

Astronomers Observe the Rotating Accretion Disk Around the Supermassive Black Hole in M77:

During the 1970s, scientists confirmed that radio emissions coming from the center of our galaxy were due to the presence of a Supermassive Black Hole (SMBH). Located about 26,000 light-years from Earth between the Sagittarius and Scorpius constellation, this feature came to be known as Sagittarius A*. Since that time, astronomers have come to understand that most massive galaxies have an SMBH at their center.

What’s more, astronomers have come to learn that black holes in these galaxies are surrounded by massive rotating toruses of dust and gas, which is what accounts for the energy they put out. However, it was only recently that a team of astronomers, using the the Atacama Large Millimeter/submillimeter Array (ALMA), were able to capture an image of the rotating dusty gas torus around the supermassive black hole of M77.

The study which details their findings recently appeared in the Astronomical Journal Letters under the title “ALMA Reveals an Inhomogeneous Compact Rotating Dense Molecular Torus at the NGC 1068 Nucleus“. The study was conducted by a team of Japanese researchers from the National Astronomical Observatory of Japan – led by Masatoshi Imanishi – with assistance from Kagoshima University.





The central region of the spiral galaxy M77. The NASA/ESA Hubble Space Telescope imaged the distribution of stars. ALMA revealed the distribution of gas in the very center of the galaxy. Credit: ALMA (ESO/NAOJ/NRAO)/Imanishi et al./NASA/ESA Hubble Space Telescope and A. van der Hoeven
Like most massive galaxies, M77 has an Active Galactic Nucleus (AGN), where dust and gas are being accreted onto its SMBH, leading to higher than normal luminosity. For some time, astronomers have puzzled over the curious relationship that exists between SMBHs and galaxies. Whereas more massive galaxies have larger SMBHs, host galaxies are still 10 billion times larger than their central black hole.

This naturally raises questions about how two objects of vastly different scales could directly affect each other. As a result, astronomers have sought to study AGN is order to determine how galaxies and black holes co-evolve. For the sake of their study, the team conducted high-resolution observations of the central region of M77, a barred spiral galaxy located about 47 million light years from Earth.

Using ALMA, the team imaged the area around M77’s center and were able to resolve a compact gaseous structure with a radius of 20 light-years. As expected, the team found that the compact structure was rotating around the galaxies central black hole. As Masatoshi Imanishi explained in an ALMA press release:

“To interpret various observational features of AGNs, astronomers have assumed rotating donut-like structures of dusty gas around active supermassive black holes. This is called the ‘unified model’ of AGN. However, the dusty gaseous donut is very tiny in appearance. With the high resolution of ALMA, now we can directly see the structure.”




Motion of gas around the supermassive black hole in the center of M77. The gas moving toward us is shown in blue and that moving away from us is in red. Credit: ALMA (ESO/NAOJ/NRAO), Imanishi et al.
In the past, astronomers have observed the center of M77, but no one has been able to resolve the rotating torus at its center until now. This was made possible thanks to the superior resolution of ALMA, as well as the selection of molecular emissions lines. These emissions lines include hydrogen cyanide (HCN) and formyl ions (HCO+), which emit microwaves only in dense gas, and carbon monoxide – which emits microwaves under a variety of conditions.

The observations of these emission lines confirmed another prediction made by the team, which was that the torus would be very dense. “Previous observations have revealed the east-west elongation of the dusty gaseous torus,” said Imanishi. “The dynamics revealed from our ALMA data agrees exactly with the expected rotational orientation of the torus.”

However, their observations also indicated that the distribution of gas around an SMBH is more complicated that what a simple unified model suggests. According to this model, the rotation of the torus would follow the gravity of the black hole; but what Imanishi and his team found indicated that gas and dust in the torus also exhibit signs of highly random motion.

These could be an indication that the AGN at the center of M77 had a violent history, which could include merging with a small galaxy in the past. In short, the team’s observations indicate that galactic mergers may have a significant impact on how AGNs form and behave. In this respect, their observations of M77s torus are already providing clues as to the galaxy’s history and evolution.





NASA’s Spitzer Space Telescope captured this stunning infrared image of the center of the Milky Way Galaxy, where the black hole Sagitarrius A resides. Credit: NASA/JPL-Caltech
The study of SMBHs, while intensive, is also very challenging. On the one hand, the closest SMBH (Sagitarrius A*) is relatively quiet, with only a small amount of gas accreting onto it. At the same time, it is located at the center of our galaxy, where it is obscured by intervening dust, gas and stars. As such, astronomers are forced to look to other galaxies to study how SMBHs and their galaxies co-exist.

And thanks to decades of study and improvements in instrumentation, scientists are beginning to get a clear glimpse of these mysterious regions for the first time. By being able to study them in detail, astronomers are also gaining valuable insight into how such massive black holes and their ringed structures could coexist with their galaxies over time.

Further Reading: ALMA, arXiv

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Across The Universe - How Badly Will Humanity Freak Out if We Discover Alien Life?

How Badly Will Humanity Freak Out if We Discover Alien Life?:

The discovery of alien life is one of those things that everyone thinks about at some point. Hollywood has made their version of first contact very clear: huge alien vessels appear over Earth’s cities, panic ensues, and Will Smith saves the day with a Windows 3.1 virus. It’s lots of fun—and who knows?—it may end up being accurate. (Not the Windows 3.1 part.) But sci-fi books and movies aside, what do we really know about our attitude to the discovery of alien life?

We have an organization (SETI) dedicated to detecting the presence of alien civilizations, and we have a prominent scientist (Stephen Hawking) warning against advertising our own presence. Those represent the extremes—actively seeking out alien life vs. hiding from it—but what is the collective attitude towards the discovery of alien life? Scientists at Arizona State University (ASU) have studied that issue and detailed their results in a new study published in the journal Frontiers of Psychology.

The team of scientists tried to gauge people’s reactions to the discovery of alien life in three separate parts of their study. In the first case, they examined media reports of past announcements about the discovery of alien life, for example the announcement in 1996 that evidence of microbial life had been found in a Martian metorite.

Secondly, they asked a sample of over 500 people what their own reactions, and the reactions of the rest of humanity, would be to the hypothetical announcement of alien life.

Thirdly, the 500 people were split into two groups. Half were asked to read and respond to a real newspaper story announcing the discovery of fossilized Martian microbial life. The other half were asked to read and respond to a newspaper article announcing the creation of synthetic life by Craig Venter.

Martian meteorite ALH84001 was found in Antarctica in 1984 by a group of meteorite hunters from the US. Scientists who studied it suggested that it contained evidence of ancient Martian microbial life. Image: By Jstuby at English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=47556214
In all three cases the life was microbial in nature. Microbial life is the simplest life form, so it should be what we expect to find. This is certainly true in our own Solar System, since the existence of any other intelligent life has been ruled out here, while microbial life has not.

Also, in all three cases, the language of the respondents and the language in the media reports was analyzed for positive and negative words. A specialized piece of software called Linguistic Inquiry and Word Count (LIWC) was used. It’s text-analysis software that scans written language and identifies instances of words that reflect positive affect, negative affect, reward, or risk. (You can try LIWC here for fun, if you like.)

Electron microscope images of the Martian meteorite ALH84001 showed chain-like structures that resembled living structures. Image: NASA

Analyzing Media Reports

The media reports used in the study were all from what the team considers reputable journalism outlets like The New York Times and Science Magazine. The reports were about things like unidentified signals from space that could have been alien in nature, fossilized microbial remains in meteorites, and the discovery of exoplanets in the habitable zones of other solar systems. There were 15 articles in total.

The authors of the study wanted to find out how people would react to the discovery of alien life, and to the discovery of potentially habitable exoplanets which might harbor life. In this artist’s illustration, exoplanets orbit a young, red dwarf star. Credit: NASA/JPL-Caltec
Overall, the study showed that language in media reports about alien life was more positive than negative, and emphasized reward rather than risk. So people generally find the potential of alien life to be a positive thing and something to be looked forward to. However, this part of the study showed something else: People were more positively disposed towards news of alien life that was microbial than they were towards alien life that could be present on exoplanets, where, presumably, it might be more than merely microbial. So, microbes we can handle, but something more advanced and a little doubt starts to creep in.

Reactions to Hypothetical Announcements of Alien Life

This part of the study aimed to assess people’s beliefs regarding how both they as individuals—and humanity as a whole—might react to the discovery of alien microbial life. The same LIWC software was used to analyze the written responses of the 500 people in the sample group.

The results were similar to the first part of the study, at least for the individuals themselves. Positive affect was more predominant than negative aspect, and words reflecting reward were more predominant than words reflecting risk. This probably isn’t surprising, but the study did show something more interesting.

When participants were asked about how the rest of humanity would respond to the announcement of alien life, the response was different. While positive language still outweighed negative language, and reward still outweighed risk, the differences weren’t as pronounced as they were for individuals. So people seem to think that others won’t be looking forward to the discovery of alien life as much as they themselves do.

Actual Reactions to the Discovery of Extraterrestrial Life

This is hard to measure since we haven’t actually discovered any yet. But there have been times when we thought we might have.

In this part of the study, the group of 500 respondents was split into two groups of 250. The first was asked to read an actual 1996 New York Times article announcing the discovery of fossilized microbes in the Martian meteorite. The second group was asked to read a New York Times article from 2010 announcing the creation of life by Craig Venter. The goal was to find out if the positive bias towards the discovery of microbial life was specific to microbial life, or to scientific advancements overall.

Saturn’s moon Enceladus could harbor microbial life in the warm salty water thought to exist under its frozen surface. Respondents in the study seemed to like that possibility. Credits: NASA/JPL-Caltech/Space Science Institute
This part of the study found the same emphasis on positive affect over negative affect, and reward over risk. This held true in both cases: the Martian microbial life article, and the artificially created life article. The type of article played a minor role in people’s responses. Results were slightly more positive towards the Martian life story than the artificial life story.

Overall, this study shows that people seem positively disposed towards the discovery of alien life. This is reflected in media coverage, people’s personal responses, and people’s expectations of how others would react.

This is really just the tip of the iceberg, though. As the authors say in their study, this is the first empirical attempt to understand any of this. And the study was only 500 people, all Americans.

How different the results might be in other countries and cultures is still an open question. Would populations whose attitudes are more strongly shaped by religion respond differently? Would the populations of countries that have been invaded and dominated by other countries be more nervous about alien life or habitable exoplanets? There’s only conjecture at this point.

Maybe we’re novelty-seekers and we thrive on new discoveries. Or maybe we’re truth-seekers, and that’s reflected in the study. Maybe some of the positivity reflects our fear of being alone. If Earth is the only life-supporting world, that’s a very lonely proposition. Not only that, but it’s an awesome responsibility: we better not screw it up!

Still, the results are encouraging for humanity. We seem, at least according to this first study, open to the discovery of alien life.

But that might change when the first alien ship casts its shadow over Los Angeles.

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Across The Universe - Maybe There’s no Connection Between Supermassive Black Holes and Their Host Galaxies?

Maybe There’s no Connection Between Supermassive Black Holes and Their Host Galaxies?:

For decades, astrophysicists have puzzled over the relationship between Supermassive Black Holes (SMBHs) and their respective galaxies. Since the 1970s, it has been understood the majority of massive galaxies have an SMBH at their center, and that these are surrounded by rotating tori of gas and dust. The presence of these black holes and tori are what cause massive galaxies to have an Active Galactic Nucleus (AGN).

However, a recent study conducted by an international team of researchers revealed a startling conclusion when studying this relationship. Using the Atacama Large Millimeter/submillimeter Array (ALMA) to observe an active galaxy with a strong ionized gas outflow from the galactic center, the team obtained results that could indicate that there is no relationship between a an SMBH and its host galaxy.

The study, titled “No sign of strong molecular gas outflow in an infrared-bright dust-obscured galaxy with strong ionized-gas outflow“, recently appeared in the Astrophysical Journal. The study was led by Yoshiki Toba of the Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and included members from Ehime University, Kogakuin University, and the National Astronomical Observatory of Japan, The Graduate University for Advanced Studies (SOKENDAI), and Johns Hopkins University.





Images from the Sloan Digital Sky Survey (SDSS) (left), and mid-infrared image from WISE (right), respectively. Credit: Sloan Digital Sky Survey/NASA/JPLCaltech
The question of how SMBHs have affected galactic evolution remains one of the greatest unresolved questions in modern astronomy. Among astrophysicists, it is something of a foregone conclusion that SMBHs have a significant impact on the formation and evolution of galaxies. According to this accepted notion, SMBHs significantly influence the molecular gas in galaxies, which has a profound effect on star formation.

Basically, this theory holds that larger galaxies accumulate more gas, thus resulting in more stars and a more massive central black hole. At the same time, there is a feedback mechanism, where growing black holes accrete more matter on themselves. This results in them sending out a tremendous amount of energy in the form of radiation and particle jets, which is believed to curtail star formation in their vicinity.

However, when observing an infrared (IR)-bright dust-obscured galaxy (DOG) – WISE1029+0501 – Yoshiki and his colleagues obtained results that contradicted this notion. After conducting a detailed analysis using ALMA, the team found that there were no signs of significant molecular gas outflow coming from WISE1029+0501. They also found that star-forming activity in the galaxy was neither more intense or suppressed.

This indicates that a strong ionized gas outflow coming from the SMBH in WISE1029+0501 did not significantly affect the surrounding molecular gas or star formation. As Dr. Yoshiki Toba explained, this result:

“[H]as made the co-evolution of galaxies and supermassive black holes more puzzling. The next step is looking into more data of this kind of galaxies. That is crucial for understanding the full picture of the formation and evolution of galaxies and supermassive black holes”.




Emission from Carbon Monoxide (Left) and Cold Dust (Right) in WISE1029 Observed by ALMA (image). Credit: ALMA (ESO/NAOJ/NRAO), Toba et al.
This not only flies in the face of conventional wisdom, but also in the face of recent studies that showed a tight correlation between the mass of central black holes and those of their host galaxies. This correlation suggests that supermassive black holes and their host galaxies evolved together over the course of the past 13.8 billion years and closely interacted as they grew.

In this respect, this latest study has only deepened the mystery of the relationship between SMBHs and their galaxies. As Tohru Nagao, a Professor at Ehime University and a co-author on the study, indicated:

“[W]e astronomers do not understand the real relation between the activity of supermassive black holes and star formation in galaxies. Therefore, many astronomers including us are eager to observe the real scene of the interaction between the nuclear outflow and the star-forming activities, for revealing the mystery of the co-evolution.”
The team selected WISE1029+0501 for their study because astronomers believe that DOGs harbor actively growing SMBHs in their nuclei. In particular, WISE1029+0501 is an extreme example of galaxies where outflowing gas is being ionized by the intense radiation from its SMBH. As such, researchers have been highly motivated to see what happens to this galaxy’s molecular gas.





Artist’s impression of the black hole wind at the center of a galaxy. Credit: ESA
The study was made possible thanks to ALMA’s sensitivity, which is excellent when it comes to investigating the properties of molecular gas and star-forming activity in galaxies. In fact, multiple studies have been conducted in recent years that have relied on ALMA to investigate the gas properties and SMBHs of distant galaxies.

And while the results of this study contradict widely-held theories about galactic evolution, Yoshiki and his colleagues are excited about what this study could reveal. In the end, it may be that radiation from a SMBH does not always affect the molecular gas and star formation of its host galaxy.

“[U]nderstanding such co-evolution is crucial for astronomy,” said Yoshiki. “By collecting statistical data of this kind of galaxies and continuing in more follow-up observations using ALMA, we hope to reveal the truth.”

Further Reading: ALMA Observatory, Astrophysical Journal

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