(note: This animation has no audio track.) – The Open University
Although many moons in the Solar System follow prograde orbits, there are some notable exceptions. The gas giant planets Jupiter, Saturn, Uranus and Neptune have several small outer moons that follow retrograde orbits; this means that they orbit their planet in the opposite direction to the planet’s rotation. In a retrograde orbit, a moon revolves in its orbit in the opposite direction from that in which the planet rotates about its axis.
The universe is the biggest and oldest thing we know. It contains all existing matter and space. And its origin marks the beginning of time as far as we understand it. We don’t know what made the formation of the universe possible, nor why it occurred. The visible universe is currently about 93 billion light years wide.
A light-year is a distance that light travels in a year, which makes the universe about 880 trillion trillion metres wide. The visible universe is, however, still expanding, and we can measure that rate of expansion. Then, working backwards, we can figure out when the universe would have begun. To the best of our knowledge, the universe formed about 13.8 billion years ago in what is commonly referred to as the Big Bang.
This image shows the universe about 370000 years after the Big Bang, which is the oldest light that we’ve been able to record with the greatest precision. The image records ancient light or cosmic microwave background. The colours show tiny temperature fluctuations from an average temperature. These indicate areas of different densities, which became the stars and galaxies of today. Red spots are a bit hotter and blue spots a bit cooler. The image was recorded between 2009 and 2013, during the Planck mission, when the space observatory was operated by the European Space Agency, in conjunction with NASA, the National Aeronautics and Space Administration. Today, the universe is very cold. On average, it is 2.7Kelvin. Kelvin is a measure of temperature with the same magnitude as degrees Celsius. But 0 Kelvin equals minus 273.15 degrees Celsius.
In the universe, the hot parts, such as stars, make up only a tiny fraction. If we wind the clock backwards, the universe gets smaller. And this means the universe was hotter in the past. When matter gets hot, solids melt and liquids boil. The hot matter glows – red at first, but it becomes bluer as the temperature goes up. Eventually, all matter is gas. So we have a bright, glowing blob of gas. Going further back in time, as the gas gets hotter, the electrons are separated from the nuclei and a plasma is made. The temperature at this point is about 3000 to 6000 Kelvin and the glowing blob is white hot. As we go back further in time, the universe gets even smaller and hotter.
The nuclei themselves, containing protons and neutrons, are broken up. The reason for the breakup of nuclei is that the individual particles and the energy of the radiation are so great that the collisions of all this hot stuff are incredibly violent. The light is no longer in the visible spectrum. It is energetic enough to be x-rays and even gamma rays. Between just 10 seconds and 1000 seconds after the Big Bang, subatomic particles, including neutrons and protons, were formed. Neutrons live for just 9 minutes when they are free. Hence only those that stuck to protons during this period survived. All of the ordinary matter present today formed in this short window of time.
At about 1 microsecond after the Big Bang, the universe was very hot, at 10 to the 10 Kelvin, and quarks formed stable particles called hadrons. Before 1 picosecond, or 10 to the minus 12 seconds, the universe was an exotic place. The gas was hotter still and the laws of physics appeared different to how we see them today. The distinction between matter and radiation, such as light, cannot be detected. The forces of electromagnetism and the weak nuclear force also become indistinguishable. At the very earliest times, the universe was so hot and dense that we cannot yet describe them accurately.
Explanation: An unusual type of solar eclipse occurred in 2012. Usually, it is the Earth’s Moon that eclipses the Sun. That year, most unusually, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun. Eventually, the alignment became perfect and the phase of Venus dropped to zero. The dark spot of Venus crossed our parent star. The situation could technically be labelled a Venusian annular eclipse with an extraordinarily large ring of fire. Pictured here during the occultation, the Sun was imaged in three colours of ultraviolet light by the Earth-orbiting Solar Dynamics Observatory, with the dark region toward the right corresponding to a coronal hole. Hours later, as Venus continued in its orbit, a slight crescent phase appeared again. The next Venusian transit across the Sun will occur in 2117. </center>
THE ORIONID meteor shower promises to dazzle stargazers with a spectacular display of shooting stars TONIGHT. But what is the best time too watch the meteor shower?
When its the Orionids meteor shower?
If you can’t view it, either it being cloudy or heavey lit area, Slooh will be Live streaming the event from tonight. Join Paul Cox, Dr. Paige Godfrey, and Bob Berman for a decidedly casual and far-ranging chat as as we train our telescopes on the Orionids. SLOOH Live Event of the Orionid Meteor Shower
The Orionids light up the night sky every year towards the end of October in “one of the most beautiful showers of the year”, according to Nasa.
The meteor shower will peak in the early of hours of Saturday (October 20) and once again in the early hours of Sunday (October 22). Sporadic meteors have already been dashing across the night sky from October 15 and should remain visible until November.
During the peak, stargazers can expect anywhere up to 50 meteors per hour, though this year Nasa believes that the numbers may not be as spectacular.
Nasa’s Jane Houston Jones said: “The Orionids peak on October 20, a dark, moonless night. Look near Orion’s club in the hours before dawn and you may see up to 10 to 15 meteors per hour. “Use binoculars to look for bright asteroid 7 Iris in the constellation Aries. Newbies to astronomy should be able to spot this magnitude 6.9 asteroids even from the city.”
What is the best time to view the Orionids meteor shower?
The peak of the Orionids will be visible anywhere on Earth in the early morning hours of tonight and tomorrow night, usually after midnight and just before dawn.
The best time for skywatchers to head outside is usually around 2am when the shower is at its most intense.
Star gazers will be aided this year by the lack of moonlight which should keep the skies clear of any hindering light pollution.
But Storm Brian will make the sky overcast tonight much of the UK as the weather bomb unleashes strong winds and rainstorms.
A Met Office spokesman said: “There’s quite a lot of cloud around this evening and overnight. The best chance of seeing them will be in the early hours before dawn.” He said that the clearest skies will be from 3am in the eastern part of England across East Anglia, the South East, Lincolnshire and the Midlands.”
To get the best views, stay away from any sources of light pollution and give your eyes some time to adjust to the dark of space.
Where will the Orionid meteor shower appear?
The Orionids derive their name from there point of origin next to the Orion constellation, which ascends in the east.
But the shower’s radiant point is mostly irrelevant because the meteors will shoot out in all sorts of directions, and usually remain unseen until about 30 degrees from the radiant.
However, if you spot a streaking meteor, you should be able to trace its path back to its origin next to Orion’s club.
What are the Orionids?
The spectacular shooting stars are remnants of the prolific Halley’s Comet, which visits Earth every 74 to 79 years.
When the comet passes through the solar system, chunks (Debris) of ice and rock break off from the comet thanks to the sun, and trail in the comet’s path. The first recorded reports of the shower date back to 1839, when it was spotted in America.
The Orionids are incredibly fast meteors and crash into Earth’s atmosphere at a speed of 66 km/s. Many of the falling stars leave ionised trails of glowing gas in their path.
Orionid Meteors Over Turkey Credit & Copyright: Tunc TezelExplanation: Meteors have been flowing out from the constellation Orion. This was expected, as mid-October is the time of year for the Orionids Meteor Shower. Pictured above, over a dozen meteors were caught in successively added exposures over three hours taken this past weekend from a town near Bursa, Turkey. The above image shows brilliant multiple meteor streaks that can all be connected to a single point in the sky just above the belt of Orion, called the radiant. The Orionids meteors started as sand sized bits expelled from Comet Halley during one of its trips to the inner Solar System. Comet Halley is actually responsible for two known meteor showers, the other known as the Eta Aquarids and visible every May. Next month, the Leonids Meteor Shower from Comet Tempel-Tuttle might show an even more impressive shower from some locations.
Eclipsosaurus Rex Image Credit & Copyright: Fred Espenak (MrEclipse.com)Explanation: We live in an era where total solar eclipses are possible because at times the apparent size of the Moon can just cover the disk of the Sun. But the Moon is slowly moving away from planet Earth. Its distance is measured to increase about 1.5 inches (3.8 centimeters) per year due to tidal friction. So there will come a time, about 600 million years from now, when the Moon is far enough away that the lunar disk will be too small to ever completely cover the Sun. Then, at best only annular eclipses, a ring of fire surrounding the silhouetted disk of the too small Moon, will be seen from the surface of our fair planet. Of course the Moon was slightly closer and loomed a little larger 100 million years ago. So during the age of the dinosaurs there were more frequent total eclipses of the Sun. In front of the Tate Geological Museum at Casper College in Wyoming, this dinosaur statue posed with a modern total eclipse, though. An automated camera was placed under him to shoot his portrait during the Great American Eclipse of August 21.
Global Aurora at Mars Image Credit: MAVEN, LASP, University of Colorado, NASAExplanation: A strong solar event last month triggered intense global aurora at Mars. Before (left) and during (right) the solar storm, these projections show the sudden increase in ultraviolet emission from martian aurora, more than 25 times brighter than auroral emission previously detected by the orbiting MAVEN spacecraft. With a sunlit crescent toward the right, data from MAVEN’s ultraviolet imaging spectrograph is projected in purple hues on the right side of Mars globes simulated to match the observation dates and times. On Mars, solar storms can result in planet-wide aurora because, unlike Earth, the Red Planet isn’t protected by a strong global magnetic field that can funnel energetic charged particles toward the poles. For all those on the planet’s surface during the solar storm, dangerous radiation levels were double any previously measured by the Curiosity rover. MAVEN is studying whether Mars lost its atmosphere due to its lack of a global magnetic field.
In my previous post “Pentestit Lab v10 – The Mail Token”, we attained usernames through Intelligence Gathering, brute forced the SMTP Service, attained login credentials, and scored our first token. Today we will take our first steps at compromising the Global Data Security website – which will include the following: