happy new year

Apollo 11 Lunar Module ascent stage photographed from Command Module

Apollo 11 Lunar Module ascent stage photographed from Command Module


(July 21, 1969) The Apollo 11 Lunar Module ascent stage, with Astronauts Neil A. Armstrong and Edwin E. Aldrin Jr. aboard, is photographed from the Command and Service Modules in lunar orbit. This view is looking west with the earth rising above the lunar horizon. Astronaut Michael Collins, command module pilot, remained with the Command/Service Module in lunar orbit while Armstrong and Aldrin explored the Moon. The Lunar Module is approaching from below. The mare area in the background is Smyth's Sea. At right center is International Astronomical Union crater no. 189.

A "Rose" of a Galaxy.

                                                       A "Rose" of a Galaxy.

In celebration of the 21st anniversary of the Hubble Space Telescope's deployment into space, astronomers at the Space Telescope Science Institute pointed Hubble's eye to an especially photogenic group of interacting galaxies called Arp 273. Pictured here is the larger of the two galaxies, known as UGC 1810. It has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars. These massive stars glow fiercely in ultraviolet light. A possible mini-spiral may be visible in the spiral arms of UGC 1810 to the upper right. It is noticeable how the outermost spiral arm changes character as it passes this third galaxy, from smooth with lots of old stars (reddish in color) on one side to clumpy and extremely blue on the other. UGC 1810 lies in the constellation Andromeda and is roughly 300 million light-years away from Earth.

This image from NASA's Wide-field Infrared Survey Explorer, or WISE, highlights the Andromeda galaxy's older stellar population in blue. It was taken by the shortest-wavelength camera on WISE, which detects infrared light of 3.4 microns. A pronounced warp in the disk of the galaxy, the aftermath of a collision with another galaxy, can be clearly seen in the spiral arm to the upper left side of the galaxy.

IC 1805

Located in the Perseus Arm of the Galaxy, the Heart nebula is a bright objet (although a telescope is needed to see it) in a region of the Galaxy where a lot of stars are forming. IC 1805 is also sometimes called the 'Running Dog nebula' because it is said to resemble a running dog when viewed through a telescope

Are you wearing a gold ring? Or perhaps gold-plated earrings? Maybe you have some gold fillings in your teeth… for that matter, the human body itself naturally contains gold — 0.000014%, to be exact! But regardless of where and how much of the precious yellow metal you may have with you at this very moment, it all ultimately came from the same place.

And no, I don’t mean Fort Knox, the jewelry store, or even under the ground — all the gold on Earth likely originated from violent collisions between neutron stars, billions of years in the past.

Recent research by scientists at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts has revealed that considerable amounts of gold — along with other heavy elements — are produced during impacts between neutron stars, the super-dense remains of stars originally 1.4 to 9 times the mass of our Sun.

The team’s investigation of a short-duration gamma-ray outburst that occurred in June (GRB 130603B) showed a surprising residual near-infrared glow, possibly from a cloud of material created during the stellar merger. This cloud is thought to contain a considerable amount of freshly-minted heavy elements, including gold.

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses – quite a lot of bling!” said lead author Edo Berger.

The mass of the Moon is 7.347 x 1022 kg… about 1.2% the mass of Earth. The collision between these neutron stars then, 3.9 billion light-years away, produced 10 times that much gold based on the team’s estimates.
by Jason Major (Universe today)
Image credit: Dana Berry, SkyWorks Digital, Inc.

SOLAR SYSTEM HD

water dance

Antennae Galaxies

                                                               Antennae Galaxies

This image of the Antennae galaxies is the sharpest yet of this merging pair of galaxies. During the course of the collision, billions of stars will be formed. The brightest and most compact of these star birth regions are called super star clusters.

The two spiral galaxies started to interact a few hundred million years ago, making the Antennae galaxies one of the nearest and youngest examples of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae image are young clusters containing tens of thousands of stars. The orange blobs to the left and right of image center are the two cores of the original galaxies and consist mainly of old stars criss-crossed by filaments of dust, which appears brown in the image. The two galaxies are dotted with brilliant blue star-forming regions surrounded by glowing hydrogen gas, appearing in the image in pink.

The new image allows astronomers to better distinguish between the stars and super star clusters created in the collision of two spiral galaxies. By age dating the clusters in the image, astronomers find that only about 10 percent of the newly formed super star clusters in the Antennae will survive beyond the first 10 million years. The vast majority of the super star clusters formed during this interaction will disperse, with the individual stars becoming part of the smooth background of the galaxy. It is however believed that about a hundred of the most massive clusters will survive to form regular globular clusters, similar to the globular clusters found in our own Milky Way galaxy. The Antennae galaxies take their name from the long antenna-like "arms" extending far out from the nuclei of the two galaxies, best seen by ground-based telescopes. These "tidal tails" were formed during the initial encounter of the galaxies some 200 to 300 million years ago. They give us a preview of what may happen when our Milky Way galaxy collides with the neighboring Andromeda galaxy in several billion years.

Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration

Clavius crater

Clavius crater

There are few lunar observers who have not devoted more or less attention to this beautiful formation, one of the most striking of telescopic objects. However familiar we may consider ourselves to be with its features, there is always something fresh to note and to admire as often as we examine its apparently inexhaustible details. It is 142 miles from side to side, and includes an area of at least 16,000 square miles within its irregular circumvallation, which is only comparatively slightly elevated above the bright plateau on the E., though it stands at least 12,000 feet above the depressed floor. At a point on the S.E. a peak rises nearly 17,000 feet above the interior, while on the W. the cliffs are almost as lofty. There are two remarkable ring-plains, each about 25 miles in diameter, associated, one with the N., and the other with the S. wall, the floors of both abounding in detail. The latter, however, is the most noteworthy on account of the curious corrugations visible soon after sunrise on the outer N. slope of its wall, resembling the ribbed flanks of some of the Java volcanoes. There are five large craters on the floor of Clavius, following a curve convex to the N., and diminishing in size from E. to W. The most easterly stands nearly midway between the two large ring-plains on the walls, the second (about two- thirds its area) is associated with a complex group of hills and smaller craters. Both these objects have central mountains. In addition to this prominent chain, there are innumerable craters of a smaller type on the floor, but they are more plentiful on the S. half than elsewhere. On the S.W. wall are three very large depressions. On the broad massive N.W. border, the bright summit ridge and the many transverse valleys running down from it to the floor, are especially interesting features. There are very clear indications of "faulting" on a vast scale where this broad section of the wall abuts on the N. side of the formation.

Antennae GalaxiES

Antennae Galaxies

This image of the Antennae galaxies is the sharpest yet of this merging pair of galaxies. During the course of the collision, billions of stars will be formed. The brightest and most compact of these star birth regions are called super star clusters.

The two spiral galaxies started to interact a few hundred million years ago, making the Antennae galaxies one of the nearest and youngest examples of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae image are young clusters containing tens of thousands of stars. The orange blobs to the left and right of image center are the two cores of the original galaxies and consist mainly of old stars criss-crossed by filaments of dust, which appears brown in the image. The two galaxies are dotted with brilliant blue star-forming regions surrounded by glowing hydrogen gas, appearing in the image in pink.

The new image allows astronomers to better distinguish between the stars and super star clusters created in the collision of two spiral galaxies. By age dating the clusters in the image, astronomers find that only about 10 percent of the newly formed super star clusters in the Antennae will survive beyond the first 10 million years. The vast majority of the super star clusters formed during this interaction will disperse, with the individual stars becoming part of the smooth background of the galaxy. It is however believed that about a hundred of the most massive clusters will survive to form regular globular clusters, similar to the globular clusters found in our own Milky Way galaxy. The Antennae galaxies take their name from the long antenna-like "arms" extending far out from the nuclei of the two galaxies, best seen by ground-based telescopes. These "tidal tails" were formed during the initial encounter of the galaxies some 200 to 300 million years ago. They give us a preview of what may happen when our Milky Way galaxy collides with the neighboring Andromeda galaxy in several billion years.

Image Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration

This Hubble image shows RS Puppis, a type of variable star known as a Cepheid variable. As variable stars go, Cepheids have comparatively long periods — RS Puppis, for example, varies in brightness by almost a factor of five every 40 or so days. RS Puppis is unusual; this variable star is shrouded by thick, dark clouds of dust enabling a phenomenon known as a light echo to be shown with stunning clarity. These Hubble observations show the ethereal object embedded in its dusty environment, set against a dark sky filled with background galaxies.

NGC

Far away, long ago, a star exploded. Supernova 1994D, visible as the bright spot on the lower left, occurred in the outskirts of disk galaxy NGC 4526. Supernova 1994D was not of interest for how different it was, but rather for how similar it was to other supernovae. In fact, the light emitted during the weeks after its explosion caused it to be given the familiar designation of a Type Ia supernova. If all Type 1a supernovae have the same intrinsic brightness, then the dimmer a supernova appears, the farther away it must be. By calibrating a precise brightness-distance relation, astronomers are able to estimate not only the expansion rate of the universe (parameterized by the Hubble Constant), but also the geometry of the universe we live in (parameterized by Omega and Lambda). The large number and great distances to supernovae measured in 1998 have been interpreted as indicating that we live in a previously unexpected universe

El Castillo Pyramid

The milky way over El Castillo Pyramid, Mexico

NASA's IMAGE

An Aurora Australis as seen from space. This amazing composite image was created with footage from NASA's IMAGE satellite in 2005.

ISS transit over the Moon...

ISS transit over the Moon...

Milky Way in the Middle of nowhere ...

Milky Way in the Middle of nowhere ...

Galaxies

These images show 6 different snapshots of galaxies at different stages of merging. It takes hundreds of millions of years for one merger to complete, so the individual stages are illustrated with different images from the fifty nine new images of colliding galaxies that make up the largest collection of Hubble images ever released together. As this astonishing Hubble atlas of interacting galaxies illustrates, galaxy collisions produce a remarkable variety of intricate structures.

1. Typically the first sign of an interaction will be a bridge of matter as the first gentle tugs of gravity tease out dust and gas from the approaching galaxies.

2. As the outer reaches of the galaxies begin to intermingle, long streamers of gas and dust, known as tidal tails, stretch out and sweep back to wrap around the cores.

3. These long, often spectacular, tidal tails are the signature of an interaction and can persist long after the main action is over.

4. As the galaxy cores approach each other their gas and dust clouds are buffeted and accelerated dramatically by the conflicting pull of matter from all directions. These forces can result in shockwaves rippling through the interstellar clouds.

5. Gas and dust are siphoned into the active central regions, fuelling bursts of star formation that appear as characteristic blue knots of young stars. As the clouds of dust build they are heated so that they radiate strongly, becoming some of the brightest infrared objects in the sky.

6. Some of the galaxies show striking, highly distorted features, with dust lanes crossing between the galaxies and long filaments of stars and gas extending far beyond the central regions. Beautifully interwoven galaxies are the twisted outcomes of these gargantuan encounters. These colossal and violent interactions between the galaxies, trigger star formation from the large clouds of gas in dazzling, dramatic bursts, creating brilliant blue star clusters.

Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech)

The Black Eye Galaxy (Messier 64)

The Black Eye Galaxy (Messier 64) is a spiral galaxy with an apparent magnitude of 9.36, lying approximately 24 million light years from Earth. It is sometimes also called the Sleeping Beauty Galaxy or Evil Eye Galaxy.

It is a popular object among amateur astronomers, as it can be easily observed in small telescopes. The Black Eye Galaxy has a bright nucleus and a dark band of dust in front of it, which earned it the nickname the Evil Eye.

The galaxy is an unusual one; the gas in its outer regions rotates in the opposite direction from the stars and gas in its inner regions. Astronomers speculate that this could be a result of M64 having absorbed a smaller satellite galaxy about a billion years ago.

The inner region spans only 3,000 light years in radius, while the outer parts extend to another 40,000 light years. The region separating the two is a site of active star formation.

Messier 64 was independently discovered by Edward Pigott and Johann Elert Bode in 1779, and then by Charles Messier, who included the galaxy in his catalogue in 1780.

The Black Eye can be found one degree east-northeast of the star 35 Comae Berenices.

Asperatus Clouds

Asperatus Clouds Over New Zealand
Image Credit & Copyright: Witta Priester

UGC10214 Tadpole Galaxy

TUGC10214  Tadpole Galaxy is a disrupted barred spiral galaxy located 400 million light years from Earth toward the northern constellation Draco. It is hypothesized that a more compact intruder galaxy crossed in front of the Tadpole Galaxy—from left to right from the perspective of Earth—and was slung around behind the Tadpole by their mutual gravitational attraction. During this close encounter, tidal forces drew out the spiral galaxy’s stars, gas, and dust, forming the conspicuous tail. The intruder galaxy itself, estimated to lie about 300 thousand light-years behind the Tadpole, can be seen through foreground spiral arms at the upper left. Following its terrestrial namesake, the Tadpole Galaxy will likely lose its tail as it grows older, the tail’s star clusters forming smaller satellites of the large spiral galaxy.

This Image is produced with the HST data from the Hubble Legacy Archives_ Processing by Bill Snyder

How is a star born?

A star is born when atoms of light elements are squeezed under enough pressure for their nuclei to undergo fusion. All stars are the result of a balance of forces: the force of gravity compresses atoms in interstellar gas until the fusion reactions begin. And once the fusion reactions begin, they exert an outward pressure. As long as the inward force of gravity and the outward force generated by the fusion reactions are equal, the star remains stable.

Clouds of gas are common in our galaxy and in other galaxies like ours. These clouds are called nebulae. A typical nebula is many light-years across and contains enough mass to make several thousand stars the size of our sun. The majority of the gas in nebulae consists of molecules of hydrogen and helium--but most nebulae also contain atoms of other elements, as well as some surprisingly complex organic molecules. These heavier atoms are remnants of older stars, which have exploded in an event we call a supernova. The source of the organic molecules is still a mystery.

Irregularities in the density of the gas causes a net gravitational force that pulls the gas molecules closer together. Some astronomers think that a gravitational or magnetic disturbance causes the nebula to collapse. As the gases collect, they lose potential energy, which results in an increase in temperature.
As the collapse continues, the temperature increases. The collapsing cloud separates into many smaller clouds, each of which may eventually become a star. The core of the cloud collapses faster than the outer parts, and the cloud begins to rotate faster and faster to conserve angular momentum. When the core reaches a temperature of about 2,000 degrees Kelvin, the molecules of hydrogen gas break apart into hydrogen atoms. Eventually the core reaches a temperature of 10,000 degrees Kelvin, and it begins to look like a star when fusion reactions begin. When it has collapsed to about 30 times the size of our sun, it becomes a protostar.

When the pressure and temperature in the core become great enough to sustain nuclear fusion, the outward pressure acts against the gravitational force. At this stage the core is about the size of our sun. The remaining dust envelope surrounding the star heats up and glows brightly in the infrared part of the spectrum. At this point the visible light from the new star cannot penetrate the envelope. Eventually, radiation pressure from the star blows away the envelope and the new star begins its evolution. The properties and lifetime of the new star depend on the amount of gas that remains trapped. A star like our sun has a lifetime of about 10 billion years and is just middle-aged, with another five billion years or so left.

Stars form from the gravitational collapse of large clouds of interstellar material. In fact, the space between stars is not empty; it is nearly empty, but not entirely. Interstellar matter, that found lying between the stars, is made from gas and dust. Granted, only about 10 percent of the mass in our Milky Way galaxy is made up of interstellar matter. But this material, as tenuous as it is, exerts a gravitational force, and as a result, it will begin to pull itself together.

As this accretion continues, the gravity becomes increasingly strong because its strength rises as the mass increases and the distance of the individual atoms decreases. Eventually this interstellar matter entirely collapses in on itself. The material at the very center is compressed by the infalling material on the outside, pushing down to get to the center. And this compression heats up the center of the collapsing cloud.
At some point, the temperature gets so extremely high at the center, it triggers a fusion reaction. All the material that has fallen in then evolves into a hot, bright star. The star will continue to shine as long as there is hydrogen gas to fuse through nuclear reactions, and the gravitational pressure pushing inward keeps the atoms very hot and tightly packed at the center.

This awesome lenticular cloud formation occured at sunset over 'sOregon Alvord desert

The Moon's orbit is indeed getting larger, at a rate of about 3.8 centimeters per year. I wouldn't say that the Moon is getting closer to the Sun, specifically, though--it is getting farther from the Earth, so, when it's in the part of its orbit closest to the Sun, it's closer, but when it's in the part of its orbit farthest from the Sun, it's farther away.

The reason for the increase is that the Moon raises tides on the Earth. Because the side of the Earth that faces the Moon is closer, it feels a stronger pull of gravity than the center of the Earth. Similarly, the part of the Earth facing away from the Moon feels less gravity than the center of the Earth. This effect stretches the Earth a bit, making it a little bit oblong. We call the parts that stick out "tidal bulges." The actual solid body of the Earth is distorted a few centimeters, but the most noticable effect is the tides raised on the ocean.

Now, all mass exerts a gravitational force, and the tidal bulges on the Earth exert a gravitational pull on the Moon. Because the Earth rotates faster than the Moon orbits (once every 27.3 days) the bulge tries to "speed up" the Moon, and pull it ahead in its orbit. The Moon is also pulling back on the tidal bulge of the Earth, slowing the Earth's rotation. Tidal friction, caused by the movement of the tidal bulge around the Earth, takes energy out of the Earth and puts it into the Moon's orbit, making the Moon's orbit bigger (but, a bit pardoxically, the Moon actually moves slower!).

The Earth's rotation is slowing down because of this. One hundred years from now, the day will be 2 milliseconds longer than it is now.

This same process took place billions of years ago--but the Moon was slowed down by the tides raised on it by the Earth. That's why the Moon always keeps the same face pointed toward the Earth. Because the Earth is so much larger than the Moon, this process, called tidal locking, took place very quickly, in a few tens of millions of years.

Many physicists considered the effects of tides on the Earth-Moon system. However, George Howard Darwin (Charles Darwin's son) was the first person to work out, in a mathematical way, how the Moon's orbit would evolve due to tidal friction, in the late 19th century. He is usually credited with the invention of the modern theory of tidal evolution.

So that's where the idea came from, but how was it first measured? The answer is quite complicated, but I've tried to give the best answer I can, based on a little research into the history of the question.

There are three ways for us to actually measure the effects of tidal friction.

* Measure the change in the length of the lunar month over time.

This can be accomplished by examining the thickness of tidal deposits preserved in rocks, called tidal rhythmites, which can be billions of years old, although measurements only exist for rhythmites that are 900 million years old. As far as I can find (I am not a geologist!) these measurements have only been done since the early 90's.

* Measure the change in the distance between the Earth and the Moon.

This is accomplished in modern times by bouncing lasers off reflectors left on the surface of the Moon by the Apollo astronauts. Less accurate measurements were obtained in the early 70's.

* Measure the change in the rotational period of the Earth over time.

Nowadays, the rotation of the Earth is measured using the Very Long Baseline Interferometry, a technique using many radio telescopes a great distance apart. With VLBI, the positions of quasars (tiny, distant, radio-bright objects) can be measured very accuarately. Since the rotating Earth carries the antennas along, these measurements can tell us the rotation speed of the Earth very accurately.

However, the change in the Earth's rotational period was first measured using eclipses, of all things. Astronomers who studied the timing of eclipses over many centuries found that the Moon seemed to be accelerating in its orbit, but what was actually happening was the the Earth's rotation was slowing down. The effect was first noticed by Edmund Halley in 1695, and first measured by Richard Dunthorne in 1748--though neither one really understood what they were seeing. I think this is the earliest discovery of the effect.

Quasar Drenched in Water Vapor

 

Quasar Drenched in Water Vapor

This artist's concept illustrates a quasar, or feeding black hole, similar to APM 08279+5255, where astronomers discovered huge amounts of water vapor. Gas and dust likely form a torus around the central black hole, with clouds of charged gas above and below. X-rays emerge from the very central region, while thermal infrared radiation is emitted by dust throughout most of the torus. While this figure shows the quasar's torus approximately edge-on, the torus around APM 08279+5255 is likely positioned face-on from our point of view.

Image credit: NASA/ESA

jupiter

These side by side images of Jupiter taken by Australian astrophotographer Anthony Wesley show the SEB in August 2009, but not in May 2010.

The Sombrero Galaxy

The Sombrero Galaxy, also known as Messier 104 (M104), is a famous unbarred spiral galaxy located in the southern skies, in the direction of Virgo constellation. It lies at a distance of 29.3 million light years from Earth. The galaxy’s designation in the New General Catalogue is NGC 4594.


The Sombrero Galaxy is known for its appearance, similar to that of a Mexican hat, with a bright white core surrounded by thick lanes of dust and a halo of globular clusters and stars, appearing almost edge-on when observed from Earth.

Messier 104 has an exceptionally large and prominent central bulge, which contains billions of very old stars that are responsible for the glow of the galaxy’s central region. The dust lanes contain a number of younger, brighter stars.

M104 is believed to contain a large black hole at its centre. The central region is quite bright across the electromagnetic spectrum. With an apparent visual magnitude of 8.98, the galaxy can’t be seen without binoculars, but it can easily be found in smaller telescopes.

The Sombrero Galaxy can be seen in 7×35 binoculars or a 4-inch telescope. The galaxy’s central bulge can be made out in a medium-sized telescope, and the dust lane is visible in larger telescopes, starting from 10-inch and 12-inch telescopes.

To distinguish the galaxy’s bulge from the disk, one needs at least an 8-inch telescope.

Images from NASA’s Spitzer Space Telescope have revealed that Messier 104 has a significantly larger and more massive halo surrounding it than previously believed, which suggests that it might really be a giant elliptical galaxy.

In 2012, infrared images from Spitzer indicated that the Sombrero Galaxy is really two galaxies in one: a large elliptical galaxy with a thin disk galaxy embedded within.

The galaxy’s halo, seen glowing in visible light images, was revealed to be the right mass and size for a large elliptical galaxy.

The discovery raised questions over the galaxy’s formation because what would usually be the most likely scenario – the giant elliptical galaxy swallowing the smaller spiral galaxy – does not make sense here because the smaller galaxy’s disk would most likely not have survived the collision.

Another theory suggests that a cloud of dust was drawn in by the gravity of the elliptical galaxy, and formed a spinning disk around the galaxy’s centre.

The Sombrero Galaxy is believed to be similar to Centaurus A, another elliptical galaxy with an embedded disk inside it, located in Centaurus constellation

Hubble captures a “lucky” galaxy alignmen

Hubble captures a “lucky” galaxy alignmen

An interesting galaxy has been circled in this NASA/ESA Hubble Space Telescope image. The galaxy — one of a group of galaxies called Luminous Red Galaxies — has an unusually large mass, containing about ten times the mass of the Milky Way. However, it’s actually the blue horseshoe shape that circumscribes the red galaxy that is the real prize in this image.

This blue horseshoe is a distant galaxy that has been magnified and warped into a nearly complete ring by the strong gravitational pull of the massive foreground Luminous Red Galaxy. To see such a so-called Einstein Ring required the fortunate alignment of the foreground and background galaxies, making this object’s nickname “the Cosmic Horseshoe” particularly apt.

The Cosmic Horseshoe is one of the best examples of an Einstein Ring. It also gives us a tantalising view of the early Universe: the blue galaxy’s redshift — a measure of how the wavelength of its light has been stretched by the expansion of the cosmos — is approximately 2.4. This means we see it as it was about 3 billion years after the Big Bang. The Universe is now 13.7 billion years old.

Astronomers first discovered the Cosmic Horseshoe in 2007 using data from the Sloan Digital Sky Survey. But this Hubble image, taken with the Wide Field Camera 3, offers a much more detailed view of this fascinating object.

This picture was created from images taken in visible and infrared light on Hubble’s Wide Field Camera 3. The field of view is approximately 2.6 arcminutes wide.


Credit: ESA/Hubble & NASA

Whirlpool Galaxy (NGC 5194 or M51a

Whirlpool Galaxy (NGC 5194 or M51a) is the first classified spiral galaxy. It was discovered by Charles Messier in 1773 and was designated as M51. But, it was first recognized as a Spiral galaxy by Lord Rosse (William Parsons) in 1845 and thus becoming the first classified spiral galaxy. It is estimated to be around 23 million light years away in the constellation of Canes Venatici. It is one of the most popular galaxies in the sky.

Steven Marx

Centaurus A may be described as having a peculiar morphology. As seen from Earth, the galaxy looks like a lenticular or elliptical galaxy with a superimposed dust lane. The peculiarity of this galaxy was first identified in 1847 by John Herschel, and the galaxy was included in the Atlas of Peculiar Galaxies (published in 1966) as one of the best examples of a "disturbed" galaxy with dust absorption. The galaxy's strange morphology is generally recognized as the result of a merger between two smaller galaxies.

The bulge of this galaxy is composed mainly of evolved red stars. The dusty disk, however, has been the site of more recent star formation; over 100 star formation regions have been identified in the disk.

by Steven Marx

Lightning's

Lightning's in the ash plume in the volcanic eruption in Eyjafjallajokull glacier in Iceland
by Sigurdur Hrafn Stefnisson

As Darkness Falls by Colin H. Sillerud