“Big Freeze”

                                                                                 The “Big Freeze” is a scientific theory of the end of the universe. Though it doesn’t entail gigantic tubs of ice cream drowning everyone, it does spell disaster for everyone. The universe has a fixed amount of energy in it, and as this energy runs out—so the theory goes—the universe slows down. In other words, there is a slow loss of heat, because heat is produced by the movement of energy particles. There is also a slowdown in movement, and supposedly, everything would eventually come to a halt. Which brings to mind the lines by T. S. Eliot: “This is the way the world ends: not with a bang but with a whimper.

                                                                The Universe may have neither a centre nor an edge, because according to Einstein’s theory of relativity, gravity bends all of space time around into an endless curve.

                                                                             The astronomy estimates there are more than 100 billion galaxies in the Universe, and our own galaxy, the Milky Way galaxy, has alone between 200-400 billion stars. So if an average galaxy has around 300 billion stars you can imagine the incredible number of all stars in our universe. — with Riaz Brahvì.

earth

                                                                       In 2004, astronomers discovered a star made entirely of diamonds. The crystallized white dwarf measures over 2,400 miles across and is composed of 10 billion trillion trillion carats. Unfortunately for treasure hunters, though, it is also 50 light years from Earth.

M39: Open Cluster in Cygnus

                                                                 Lying just at the limit of human perception is a picturesque starfield containing one of the larger open clusters on the northern sky. Spanning an angle larger than the Moon, M39's relatively few stars lie only about 800 light years distant toward the constellation of Cygnus. The above picture of M39 is a mosaic of 33 images taken by the WIYN telescope on Kitt Peak in Arizona, USA. The stars in M39 are all about 300 million years old, much younger than the 5,000 million years of our Sun. Open clusters, also called galactic clusters, contain fewer and younger stars than globular clusters. Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy.

sun

                                                        Sunspots appear as darker regions on the Sun. They are regions of concentrated magnetic field and usually appear before solar flares and coronal mass ejections. Sunspots are representative of solar activity, and are therefore more likely to appear during solar maximum. Though just a small spot on the Sun, some can grow to be bigger than Jupiter! While it is never safe to look at the Sun directly, if you have the right filter, you can sometimes see them without any magnification. They are not holes, but cooler regions, making them appear dark against the hot, bright surface of the rest of the Sun.

"O" on the beach...

Seasons on Mars

    

                                                                    

The planet experiences all four seasons that the Earth does, but, since the year is longer on the planet, the axial tilt is different, and Mars has a more eccentric orbit than Earth, the seasons are not the same length as each other or the same in each hemisphere.Why does Mars have seasons? Because, like Earth, its axis is tilted away from the Sun.

On Mars, in the northern hemisphere to be exact, spring is the longest season. The Martian year is nearly twice as long as an Earth year(1.88 years), the seasons last longer as well. Here is how a Martian year in the north breaks down: Spring…7 months, Summer…6 months, Fall…5.3 months, and Winter…just over 4 months. Even in the summer months it is very cold. Temperatures at the height of the season may not top -20 C. In the south the temperatures can be as much as 30 C warmer during the same season. The great fluctuations in temperature and the difference in warmth between hemispheres can cause huge dust storms. Some can affect just a small area, while others can cover the entire planet. The larger storms usually occur when the planet is near its aphelion(closest point to the Sun). When there are global dust storms there is no way for scientists to visualize the planet’s surface.

Scientific evidence suggests that the planet has seen warmer and colder periods over its existence, much like Earth has. A radar instrument on the Mars Express has turned up water ice, a mineral mapping instrument has discovered chemicals formed in a wet environment, and its camera has picked out features on the surface formed by running water. The cameras also show a huge valley, Kasei Valles, that was probably carved by a gigantic glacier. Additional research has shown evidence of glaciers at varying latitudes. This would seem to indicate that the planet formerly had a different degree of axial tilt, which would have made for a much different environment and potential seasonal variations.

NGC

NGC 2024 (Flame Nebula) one of the most remarkable reflection nebulae in the night sky, has an underlay of glowing Ha (red) emission but is strongly overlaid with reflected light from Alnitak resulting in almost unique and beautiful colours, ranging from shell-pink through yellow to deep orange. Additional dark gas and dust lies in front of the bright part of the nebula and this is what causes the dark network that appears in the center of the glowing gas.

JUPITER

                                                                       Jupiter’s moon Ganymede is, with a diameter of 5,268 km the largest moon in the Solar System, even larger than the planet Mercury. It also has the highest mass of all moons, with 2.025 times the mass of the Earth’s Moon. It is the seventh moon outward from Jupiter and one of the four so called Galilean moons (the other three are: Io, Europa and Callisto – all discovered by Galileo Galilei in the year 1610.) 
                                     Ganymede orbits Jupiter at a distance of 1,070,400 km and completes a revolution every seven days and three hours. Like most known moons, Ganymede is tidally locked, with one side of the moon always facing toward the planet. Ganymede participates in orbital resonances with Europa and Io: for every orbit of Ganymede, Europa orbits twice and Io orbits four times. 
                                                                                                        Its surface is composed of two main types of terrain. Dark regions, saturated with impact craters and dated to four billion years ago, cover about a third of the satellite. Lighter regions, crosscut by extensive grooves and ridges and only slightly less ancient, cover the remainder. The cause of the light terrain’s disrupted geology was likely the result of tectonic activity brought about by tidal heating. 
                                             Ganymede is composed of approximately equal amounts of silicate rock and water ice, with additional volatile ices such as ammonia. Water ice seems to be ubiquitous on the surface. The brighter, grooved regions have a more icy composition than the dark regions. Besides water, analysis has revealed several other materials on Ganymede’s surface, like carbon- and sulfur dioxide and various organic compounds. Especially the dark regions contain clays with organic materials. 
                                                                                                                  The large craters on Ganymede have almost no vertical relief and are quite flat. They lack central depressions common to craters. This is probably due to slow and gradual adjustment to the soft icy surface. These large phantom craters range from 50 to 400 km in diameter. Both bright and dark rays of ejecta exist around Ganymede’s craters — rays tend to be bright from craters in the light, grooved terrain and dark from the dark cratered.
                                                                                                                                A saltwater ocean, which could potentially also host life, is believed to exist nearly 200 km below Ganymede’s surface, sandwiched between layers of ice. The magnesium- and sodium sulfates that were also found, likely originate from this subsurface ocean. Just how deep this ocean is, and whether it exists in pockets or as a continuous band around the moon, are questions the JUICE- team hopes to answer. (JUICE is the next planned mission to the Jovian moons.)
                                Ganymede appears to be fully differentiated, consisting of an iron-rich, liquid core, silicate mantle and an outer, very thick (maybe 800 km thick) ice mantle which might contain some rock mixed in. The existence of the iron-rich core provides a natural explanation for the intrinsic magnetic field of Ganymede. 
                 The convection in the liquid iron, which has high electrical conductivity, is the most reasonable model of magnetic field generation. Ganymede is the only moon in the Solar System known to possess a magnetosphere, although the meager magnetosphere is buried within Jupiter’s much larger magnetic field. But, this field is powerful enough to generate an aurora, like Earth’s. 
                                                                                                    Ganymede also has polar caps which extend to 40° latitude, likely composed of water frost. The caps’ formation is due to the migration of water to higher latitudes and bombardment of the ice by plasma. The presence of a magnetic field on Ganymede results in more intense charged particle bombardment of its surface in the unprotected polar regions; sputtering then leads to redistribution of water molecules, with frost migrating to locally colder areas within the polar terrain.
                          Ganymede has a tenuous oxygen atmosphere that includes O, O2, and possibly O3 (ozone). But, the atmosphere is far too thin to support life as we know it. Another minor constituent of the Ganymedian atmosphere is atomic hydrogen. 
                                                                   Ganymede probably formed by an accretion in Jupiter’s disk of gas and dust surrounding Jupiter after its formation. The accretion of Ganymede probably took about 10,000 years, much shorter than the 100,000 years estimated for Callisto. Ganymede formed closer to Jupiter then Callisto, where the disk was denser, which explains its shorter formation timescale.
                                                                                                                           

Several probes (Pioneer 10 and 11, Voyager 1 and 2, and Galileo) flying by or orbiting Jupiter have explored Ganymede. The next planned mission to the Jovian system is the Jupiter Icy Moon Explorer (JUICE), due to launch in 2022. After flybys of the other three Galilean moons, the probe is planned to enter orbit around Ganymede in 2032.

    

A Fisheye View of Comet Hale-Bopp

                                                  Thousands of stars, several constellations, a planet and a comet all graced the western horizon over Ujue, Spain just after sunset on April 4th, 1997. Because the picture was taken with a fisheye lens, much of the whole night sky is visible. Comet Hale-Bopp, with both tails blazing, appears right of center. The brightest star is Sirius near the edge, well to the left of the constellation Orion. The red star above the belt of Orion is Betelgeuse, while the red star near the center is Aldebaran, just to the left of the bright Pleaides star cluster. Many other interesting astronomical objects are visible, including zodiacal light, which is the diffuse triangular glow in the center. Even the planet Mercury appears just over the horizon.

Pillars of creation

                                                               By Adam Block

Credit: NASA/JPL-Caltech

                                           At approximately 2.5 million light-years away, the Andromeda Galaxy, or M31, is our Milky Way's largest galactic neighbor. The entire galaxy spans 260,000 light-years across -- a distance so large, it took 10 GALEX images stitched together to produce this view of the galaxy next door.

The wisps of blue making up the galaxy's spiral arms are neighborhoods that harbor hot, young, massive stars. Meanwhile, the central orange-white ball reveals a congregation of cooler, old stars that formed long ago.

Andromeda is so bright and close by that it is one of only three galaxies that can be spotted from Earth with the naked eye. This view is two-color composite, where blue represents far-ultraviolet light, and red is near-ultraviolet light.

Credit: NASA/JPL-Caltec         

Mercury

While Mercury is the closest planet to the Sun, its temperatures can reach a biting -280 degrees Fahrenheit as Mercury lacks the atmospheric pressure necessary to trap heat. Venus, on the other hand, has a thick atmosphere to trap heat and is markedly hotter than Mercury, despite being farther away from the Sun.

This is how big the Andromeda Galaxy, which is 2.5 million light-years away from Earth, would look in our sky if it were brighter.

Eyjafjallajokull !!!

                                         Eyjafjallajoukll !!!

M81

This is a deep rendition of the M81 (bode's nebula) galaxy including Ha datas. The shot is an LLRGB+Ha composition of several images taken during years in different locations and shows also the irregular galaxy Holmberg X and part of the flux nebula present in this area of the sky.