Ten things you may not know about the Saturn
- Saturn Is Both Hot and Cold - Saturn is, on average, 900 million miles from the Sun, making it the sixth farthest planet out in the solar system. Because of this distance, the cloud tops of the planet’s thick atmosphere do not get much solar energy and are quite cold, at -285 degrees Fahrenheit. But the interior of the planet is much warmer, probably due to energy being generated by sinking helium. Saturn emits two and a half times as much heat as it receives from the sun.
- Aurora on Saturn - Saturn experiences the aurora just as Earth does. Auroras are sometimes also called the Northern Lights (or Southern Lights, for those in the Southern Hemisphere). When solar plasma interacts with magnetic fields in the atmosphere of Saturn, particles become excited and emit light.
- Saturn Can Be a Stormy Place - Besides magnetic storms/aurorae, spacecraft visiting Saturn have observed some strong storm systems, including one hurricane-like storm with an eye and a long-lasting hexagonal cloud formation.
- Saturn Could Float on Water - It’s a fact often spouted about Saturn, but what does this mean? Saturn is the least dense of the planets. Considering its large size, one would expect it be more massive, or weigh more. But the planet is mostly gas (96% hydrogen) with a small rocky core.
- There Are Thousands of Rings - Although Saturn has a handful of main ring systems, the entire system is actually composed of thousands of tiny rings. The rings themselves are made of billions of pieces of ice, rock, and dust.
- Saturn’s Rings Occasionally “Disappear” - Saturn tilts in its orbit with respect to Earth. Therefore, sometimes Saturn shows a wide expanse of its rings, and sometimes the planet is tilted so that the rings are pointing directly at Earth. Because the ring system is extremely narrow, the rings can seem to disappear when they are aimed edge-on to Earth.
- Its Moons Could Hold Life - Saturn’s largest moon, Titan, is the only other body in the solar system besides Earth to have a substantial nitrogen atmosphere. It also has lakes, although these lakes are made of methane and not water. Its moon Enceladus also has a wet surface with icy geysers.
- Shepherd Moons - Saturn has small moons that can be found near its giant ring system that keep the rings in line. Just as a shepherd tends to his flock by keeping the sheep in line and ushering them from one field to another, a shepherd moon influences the rocks and ice that make up Saturn’s ring system, its gravity helping to keep the particles from drifting out of line.
- No One Discovered Saturn - Saturn is easy to see without binoculars or a telescope. When it is up in the sky, it looks just like a bright star. Its existence has been known by many different cultures for thousands of years, even though they haven’t always understood just what it is they were looking at.
- Cassini Discovered Many Features of Saturn - Cassini’s name is often associated with Saturn. Giovanni Domenico Cassini was an Italian astronomer who discovered the division in Saturn’s rings that is now named after him. He also was the first to study four of Saturn’s moons. A spacecraft sent to explore Saturn was named after Cassini.
Need more information about Saturn? Read Saturn Facts.
Source: NASA, GIF from B and C
Mars-Inspired Art, Commissioned by NASA, Births Strange Sci-Fi Photos
This magnificent view of the region around the star R Coronae Australis was created from images taken with the Wide Field Imager (WFI) at ESO’s La Silla Observatory in Chile. R Coronae Australis lies at the heart of a nearby star-forming region and is surrounded by a delicate bluish reflection nebula embedded in a huge dust cloud. The image reveals surprising new details in this dramatic area of sky.
The star R Coronae Australis lies in one of the nearest and most spectacular star-forming regions. This portrait was taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image is a combination of twelve separate pictures taken through red, green and blue filters.
This image shows a section of sky that spans roughly the width of the full Moon. This is equivalent to about four light-years at the distance of the nebula, which is located some 420 light-years away in the small constellation of Corona Australis (the Southern Crown). The complex is named after the star R Coronae Australis, which lies at the centre of the image. It is one of several stars in this region that belong to the class of very young stars that vary in brightness and are still surrounded by the clouds of gas and dust from which they formed.
The intense radiation given off by these hot young stars interacts with the gas surrounding them and is either reflected or re-emitted at a different wavelength. These complex processes, determined by the physics of the interstellar medium and the properties of the stars, are responsible for the magnificent colours of nebulae. The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles. The young stars in the R Coronae Australis complex are similar in mass to the Sun and do not emit enough ultraviolet light to ionise a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red colour seen in many star-forming regions.
The huge dust cloud in which the reflection nebula is embedded is here shown in impressively fine detail. The subtle colours and varied textures of the dust clouds make this image resemble an impressionist painting. A prominent dark lane crosses the image from the centre to the bottom left. Here the visible light emitted by the stars that are forming inside the cloud is completely absorbed by the dust. These objects could only be detected by observing at longer wavelengths, by using a camera that can detect infrared radiation.
R Coronae Australis itself is not visible to the unaided eye, but the tiny, tiara-shaped constellation in which it lies is easily spotted from dark sites due to its proximity on the sky to the larger constellation of Sagittarius and the rich star clouds towards the centre of our own galaxy, the Milky Way.
Image: ESO [high-resolution]
Hubble Sees a Lonely Galactic Island
In terms of intergalactic real estate, our solar system has a plum location as part of a big, spiral galaxy, the Milky Way. Numerous, less glamorous dwarf galaxies keep the Milky Way company. Many galaxies, however, are comparatively isolated, without close neighbors. One such example is the small galaxy known as DDO 190, snapped here in a new image from the NASA/ESA Hubble Space Telescope. (“DDO” stands for the David Dunlap Observatory, now managed by the Royal Astronomical Society of Canada, where the catalog was created).
DDO 190 is classified as a dwarf irregular galaxy as it is relatively small and lacks clear structure. Older, reddish stars mostly populate DDO 190’s outskirts, while some younger, bluish stars gleam in DDO 190’s more crowded interior. Some pockets of ionized gas heated up by stars appear here and there, with the most noticeable one shining towards the bottom of DDO 190 in this picture. Meanwhile, a great number of distant galaxies with evident spiral, elliptical and less-defined shapes glow in the background.
DDO 190 lies around nine million light-years away from our solar system. It is considered part of the loosely associated Messier 94 group of galaxies, not far from the Local Group of galaxies that includes the Milky Way. Canadian astronomer Sidney van der Bergh was the first to record DDO 190 in 1959 as part of the DDO catalog of dwarf galaxies.
Although within the Messier 94 group, DDO 190 is on its own. The galaxy’s nearest dwarf galaxy neighbor, DDO 187, is thought to be no closer than three million light-years away. In contrast, many of the Milky Way’s companion galaxies, such as the Large and Small Magellanic Clouds, reside within a fifth or so of that distance, and even the giant spiral of the Andromeda Galaxy is closer to the Milky Way than DDO 190 is to its nearest neighbor.
Hubble’s Advanced Camera for Surveys captured this image in visible and infrared light. The field of view is around 3.3 by 3.3 arcminutes.
A version of this image was entered into the Hubble’s Hidden Treasures Image Processing Competition by contestant Claude Cornen. Hidden Treasures is an initiative to invite astronomy enthusiasts to search the Hubble archive for stunning images that have never been seen by the general public. The competition has now closed and the results will be published soon.
Image Credit: ESA/Hubble & NASA
Our X-Ray Universe
1. New X-ray Image Shows Jupiter’s Powerful Sky Lights
X-ray auroras observed by the Chandra X-ray Observatory overlaid on a simultaneous optical image from the Hubble Space Telescope.
2. X-ray Stripes in Tycho Supernova
This image comes from a very deep Chandra observation of the Tycho supernova remnant. Low-energy X-rays (red) in the image show expanding debris from the supernova explosion and high energy X-rays (blue) show the blast wave, a shell of extremely energetic electrons. These high-energy X-rays show a pattern of X-ray “stripes” never previously seen in a supernova remant.
3. Youngest Exploding Star Discovered
The remnant known as G1.9+0.3 (shown here) came from the most recent supernova in our galaxy. To determine the age of the stellar explosion, astronomers tracked how quickly the remnant was expanding, by comparing a radio image from 1985 (blue) to an X-ray image taken in 2007 (orange).
4. NASA Spots Most Crowded Space Collision Ever
The most crowded collision of galaxy clusters has been identified by combining information from NASA’s Chandra X-ray Observatory, Hubble Space Telescope and the Keck Observatory on Mauna Kea, Hawaii. The system MACSJ0717.5+3745 (or MACSJ0717 for short) is located about 5.4 billion light years from Earth.
5. Colossal Cosmic Collision Reveals Mysterious Dark Matter
Hot gas detected by Chandra in X-rays is seen as two pink clumps that contain most of the normal matter in the two clusters. The bullet-shaped clump on the right is hot gas from one cluster, which passed through the hot gas from the other larger cluster. Other telescopes were used to detect the bulk of the matter in the clusters, which turns out to be dark matter (highlighted in blue).
6. Echo of Ancient Cosmic Explosion Seen
The Large Magellanic Cloud, which harbors the remnants of supernova 0509-67.5. Light echoes from an ancient explosion have been spotted bouncing off of nearby dust clouds.
This name derives from its appearance as a dim “milky” glowing band arching across the night sky, in which the naked eye cannot distinguish individual stars.
20 Things You Didn’t Know About Eclipses
1 The longest total solar eclipse of the century occurred on July 22 over India, Nepal, Bhutan, and China. It peaked over the Pacific Ocean, but even there the darkness lasted a mere 6 minutes and 29 seconds.
2 Fast and furious: The moon’s shadow zooms across Earth’s surface at up to 5,000 miles per hour.
3 Canadian astronomer and renowned eclipse chaser J. W. Campbell traveled the world for 50 years trying to see 12 different eclipses. He ran into overcast skies every time.
4 Don’t repeat J. W.’s mistakes: Monsoon season throughout south Asia means that there is a good chance the eclipse this July will be clouded out too.
5 Just before full eclipse, dazzling “Baily’s beads” appear where sunlight shines through valleys on the moon. The last bead creates the impression of a diamond ring in the sky.
6 On eclipse-viewing expeditions, this phenomenon is frequently accompanied by a marriage proposal.
7 The beautiful symmetry of a total solar eclipse happens because—by pure chance—the sun is 400 times larger than the moon but is also 400 times farther from Earth, making the two bodies appear the exact same size in the sky.
8 In case you were thinking about relocating: Earth is the only place in the solar system where that happens.
9 Other planets get other kinds of fun, though. Jupiter can have a triple eclipse, in which three moons cast shadows on the planet simultaneously. The event is easily visible through a backyard telescope.
10 The Chinese word for solar eclipse is shih, meaning “to eat.” In ancient China people traditionally beat drums and banged on pots to scare off the “heavenly dog” believed to be devouring the sun.
11 Then again, China also produced the first known astronomical recordings of solar eclipses, inscribed in pieces of bone and shell called “oracle bones,” from around 1050 B.C. or earlier.
12 By comparing those ancient records with modern calculations of eclipse patterns, scientists have determined that the day is 0.047 second longer today than it was back then.
13 Tidal friction, which causes that lengthening of the day, is also making the moon drift away. In about 600 million years it will appear too small to cover the sun, and there will be no more total solar eclipses.
14 In any given location, a total solar eclipse happens just once every 360 years on average.
15 Luckiest place on Earth Carbondale, Illinois, will beat the odds: Folks there will see an eclipse on August 21, 2017, and again on April 8, 2024.
16 In contrast, everyone on the night side of the world can see a lunar eclipse, where the moon slips into Earth’s shadow.
17 During a total lunar eclipse, the moon takes on a deep reddish hue due to the sunlight filtering through our atmosphere—the cumulative glow of all the world’s sunsets.
18 While stranded in Jamaica, Christopher Columbus was famously saved by the lunar eclipse of February 29, 1504, which he had read about in his almanac. After a fracas with the locals, Columbus warned that the moon would disappear if they did not start supplying his men with food.
19 When the moon vanished, the locals promptly complied, and Columbus breathed a huge sigh of relief: His almanac was calibrated for Germany, and he was not sure that he had adjusted correctly for local time.
20 Who knows—it might be useful to you, too. The next lunar eclipse visible from the United States will take place on December 21, 2010.
The Natural Satellite
(Source: Flickr / shoulderops)
Last Launch: Dan Winters and the Shuttle Program
What are Quasars?
In the 1960s, astronomers measured strong radio emissions from faint, star-like points. These were called “quasars” (shortened from “quasi-stellar radio source”) and although they look optically identical to stars, astronomers soon discovered that quasars are moving away from us at high speeds, meaning that they’re actually incredibly far away. They’re also quite small, only about the size of our solar system, and so in order to appear as bright as stars quasars must be emitting enormous amounts of electromagnetic radiation: as much energy per second as a thousand galaxies. The only currently-known event that would produce such a high-energy output is matter interacting with supermassive black holes, which are at the centre of almost all galaxies, including our own. So, quasars are believed to be supermassive black holes at the centres of young galaxies. The energy we see is produced when huge quantities of gas spirals rapidly into the gravitational whirlpool, becoming heated to temperatures of millions of degrees—then part of it escapes as hot wind or superheated beams that shoot away from the black hole’s accretion disk. We’ve observed over 60,000 of them so far, the closest at 780 million light-years away and the furthest at 12 billion, nearer to the birth of the universe than to us. It’s thought that most galaxies have gone through an active stage as a quasar, but are now quiet because they’ve exhausted their supplies of matter to feed their central black hole.
Astronomy Photographer of the Year 2011 Winners
New Planet Found: Molten “Mars” Is “Right Around the Corner”
Magma may cover UCF-1.01, which orbits scorchingly close to its star, as shown in an artist’s concept.
In a surprise find, astronomers have discovered a planet possibly covered with oceans of magma “right around the corner.”
A research team has discovered masses thought to be “seeds” that form and grow massive black holes at the center of the Milky Way Galaxy, about 30,000 light-years from our solar system in the direction of Sagittarius.