Any idea how deep the eye could go if there was no atmosphere to scatter starlight? Ever wonder what optical and physical principles limit the eye's ability to see small, faint things? Have you given thought to how the "why" of astronomy changed before and after the telescope? In this article Jeff Barbour explores the limits of human sight - with and without the telescope. Learn more about the equipment available to contemporary amateurs making backyard astronomy the "extra-terrestrial" hobby of choice.

Red dwarfs are smaller and cooler than our own Sun, but they account for 70% of the stars in our galaxy. Astronomers have wondered why there are so many red dwarfs, but they never seem to have protoplanetary discs of dust surrounding them, indicating the formation of new planets. These stars are too small to remove dust the way larger stars do it, but astronomers from UCLA think they could be using a process called "stellar wind drag". Even though they're smaller, red dwarfs can have very intense magnetic fields, producing a powerful solar wind. It's this solar wind that removes the dust, hiding evidence of planet formation.

Scientists at the European Space Agency now believe that Huygens landed with a splat when it reached the surface of Titan last Friday. They reached this conclusion because the probe's downward-facing High Resolution Thermal Imager camera lens has accumulated material since Huygens landed. This means that the probe has probably been settling down into the muck. Another possiblity, though, is that it steamed hydrocarbons off the surface which are collecting on the lens.

Greetings, fellow SkyWatchers! Is it back? Yes. But this time it's Antares and Mars! The Moon will be out in full force this week - but what a wonderful place to explore. There is no astronomical delight more loaded with detail than our own natural satellite, so join us as we walk in the Alpine Valley, climb Mons Pico, survey the terrain of Clavius and even scale the "Great Wall"! There be a grand lunar occultation this week and the "Magnificent Machholz" will perform a 'fly-by' on Mirfak. Not enough? Then lend me your ears as you'll discover Radio JOVE. We'll color the cloudy skies with atmospheric phenomena and learn which "Twin" has many secrets! So open your eyes to the skies...

Because here's what's up!

Here's a beautiful 1280x1024 desktop wallpaper of barred spiral galaxy NGC 1300 taken by the Hubble Space Telescope. This image was unveiled last week at the annual meeting of the American Astronomical Society. Barred spirals are different from regular spiral galaxies because the arms don't spiral all the way to the centre of the galaxy, but instead are connected to straight bars that contain the nucleus of the galaxy. The galaxy lies 69 million light-years away in the constellation of Eridanus.

Most large galaxies have the familiar spiral shaped disc surrounding a central bulge. But when and how do these galaxies take on their characteristic shape? New observations from the European Space Agency surveying 195 galaxies have given astronomers some clues. They've theorized that large galaxies go through a process called "spiral galaxy rebuilding", where galaxies collide, merge, and then begin a period of furious star formation. Part of the gas that didn't fall in rebuilds a disc around the galactic core creating a new spiral galaxy. This process could be repeated many times, building up the galaxy over billions of years.

After a seven year journey, the European Space Agency's Huygens probe is now on the surface of Titan. The probe entered Titan's smoggy atmosphere right on time, and slowed itself down using a series of parachutes. It then gathered data using its camera and science instruments for just over 2 hours until it landed. The probe then relayed all its data through Cassini back to Earth, where scientists will be poring over it for years. Preliminary data indicate that the probe did land safely on some kind of solid surface, but the controllers aren't sure what it was yet. Photographs and more results will be announced later today. (Make sure you check the forum, where we're posting links to pictures as we get them.)

The powerful W. M. Keck Observatory in Hawaii took this image of a dying star nicknamed the "Water Fountain Nebula". This nebula is 6500 light-years away in the direction of the constellation Scorpius, and was imaged at near-infrared wavelengths. The double corkscrew structure of the nebula indicates that there's probably a rapidly spinning remnant at the centre which is blasting out twin jets of material. By taking photos of the nebula again in a few years, astronomers will be able to understand how nebulas like this evolve over time.

A researcher from Indiana University Bloomington has discovered what could be primordial hydrogen, unchanged since the Big Bang. This hydrogen was found in galaxy UGC 5288, located 16 million light years away from Earth. When studied with the National Science Foundation's Very Large Array radio telescope in New Mexico, the galaxy seems to be surrounded by a huge disk of hydrogen gas. This could be a place to examine pristine hydrogen that hasn't been "polluted" by heavier elements created in stars.

A dense globular cluster near the heart of the Milky Way has been found to contain dozens of rapidly-spinning microsecond pulsars. The discovery was made using the 100-meter Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. Many of the pulsars are interesting, too; there are 13 in binary systems, and two that rotate 600 times a second - as fast as a household blender. The discovery of this many pulsars in a star cluster should keep astronomers busy for years, gaining insight into both the nature of these objects, and the conditions they formed in.

NASA's Deep Impact spacecraft lifted off from Florida's Cape Canaveral on Wednesday, beginning a six-month cruise to smash a hole in a comet. If everything goes well, the spacecraft will reach Comet Tempel 1 on July 4, 2005 deploying an impactor that will carve out a large crater. The resulting explosion should be the equivalent of 4 tonnes of TNT, and could be bright enough to be seen with the unaided eye back on Earth. Deep Impact will be watching the explosion from a safe distance of 500 km, and should get a unique view of the comet's composition, and what lies under its surface.

This image, taken by the Hubble Space Telescope, shows the nearby Small Magellanic Cloud - a satellite galaxy located 210,000 light-years away. Hubble's powerful optics have helped astronomers discover a population of infant stars embedded in the nebula NGC 346. Although there are many regions of star formation in the Milky Way, our companion galaxy is much smaller and lacks many of heavier elements forged in stars. This means that star formation in the SMC is much more like the star formation of the early Universe, before many of the heavier elements that make our planets had formed (carbon, iron, oxygen etc).

The W.M. Keck Observatory in Hawaii took this photograph of two galaxies about to collide over 5 billion light-years away from us. The image was possible because of the new laser guide star system for adaptive optics which corrects the distorting effects of the Earth's atmosphere. This allows Keck to have nearly the same view as space-based observatories like Hubble. Both galaxies in this collision are mature, and seem to have used up all their gas. This won't create spectacular amounts of new star formation, which is what happens with less mature galaxies.

Astronomers using the giant Gemini South 8-metre telescope in Chile have spotted what seems to be a collision between two planet-sized objects orbiting the nearby star Beta Pictoris. A collision like this would create a lot of dust, but the star is like a powerful fan that should quickly blow it all away. Based on the amount of dust still there, astronomers think the collision happened only 100 years ago, or so. This is exactly like the scenario astronomers believe our own Solar System went through 5 billion years ago as the various planets formed through multiple collisions.

On Friday, January 14, the European Space Agency's Huygens probe will plunge through the atmosphere of Saturn's smog-enshrouded moon Titan. If all goes as planned, the spacecraft will have two hours to record everything it can about the moon's atmosphere before it meets an unknown fate on the surface - it could land with a splash, splat, or a smash. Huygens will reach Titan at 1013 UTC (5:15 am EST), and then deploy its parachute a few minutes after that. It will reach the surface by 1234 UTC (7:34 am EST), and data about the journey will arrive at Earth shortly after.

The Hubble Space Telescope has helped to reveal a trio of massive, young star clusters which might have been formed by smaller clusters merging together. This tightly packed group of clusters were found in the active star forming region of NGC 5461 (located inside spiral galaxy M101), which is located 23 million light-years away in the constellation of Ursa Major. These super clusters can contain the mass of more than 1 million suns, and it's believed that they're the precursors to massive globular clusters. In NGC 5461, the various clusters are distinct, but interacting with each other, and will eventually merge into a single, super cluster.

New observations using NASA's Far Ultraviolet Spectroscopic Explorer (FUSE) satellite have given astronomers evidence that their assumptions and calculations about white dwarf stars are correct. FUSE made detailed observations of Sirius B, which is 10,000 times dimmer than its companion Sirius A (the brightest star in the sky). You can only measure the mass of a star in a binary system like this; you can observe the two stars' orbit, get the period, and then find the sum of the two star masses. These new observations helped astronomers determine Sirius B's size and mass within 1%.

One mystery has been puzzling astronomers for a few years now; strange distant clouds of intensely glowing material located billions of light-years away. They've even struggled to come up with a name, and have settled for "blobs". Using NASA's Spitzer Space Telescope, astronomers have caught a glimpse inside the blobs, and discovered evidence that they surround multiple galaxies which could be in the process of merging together. Under visible light, these galaxies are unremarkable, but Spitzer uncovered that they're some of the brightest galaxies in the Universe. If the blobs are created by galactic mergers, astronomers will need to figure out why they're putting out so much material.

Engineers at NASA and the European Space Agency have calculated Huygen's descent through Titan's atmosphere tomorrow, and they think they know where it'll land. The probe will fall by parachute for about 2 hours from an altitude of 160 km (99 miles) until it reaches the surface. During this descent, it will be taking pictures and measuring the atmosphere with five science instruments. All these data will be sent to Cassini, and then relayed back to Earth. Controllers are hoping that Cassini will get a chance to take a panoramic picture of Titan's surface as it descends, slowly spinning, to help explain the strange formations uncovered by Cassini on an earlier flyby.

Astronomers recently announced the discovery of Sedna, a nearly Pluto-sized object on a 12,500 year-long orbit around the Sun. New computer simulations from the Southwest Research Institute demonstrate that Sedna could formed out past the orbit of Pluto, instead of being created closer to the Sun, and then ejected by the gravity of the gas giants. If this happened, it would mean that the zone of planetary formation in our Solar System could extend much further than previously believed, and there could be other objects like Sedna lurking in outer reaches.

An international team of astronomers think they've found the missing link between modern galaxies like our own Milky Way to the Big Bang. The team spent 10 years mapping out the distribution of 220,000 galaxies measured as part of an extensive survey of galaxy position and motion. Shortly after the Big Bang, the Universe contained slight irregularities, created by subatomic processes and sound waves moving through the superhot afterglow. These irregularities were amplified by gravity, eventually pulling material into the first stars and galaxies.

Last month's catastrophic earthquake and tsunami were powerful enough that they actually changed the Earth's rotation, decreased the length of day, and moved the North Pole. Not much, of course, but enough that scientists can actually measure the effect. Scientists from NASA found that the length of the day shortened by 2.68 microseconds, and the North Pole shifted by 2.5 centimetres (1 inch). The Sumatran earthquake registered as a 9 on the Richter scale, making it the 4th largest earthquake measured in 100 years.

Astronomers have found three red supergiant stars which are huge; bigger than anything previously discovered. The three stars are called KW Sagitarii (9,800 light-years away), V354 Cephei (9,000 light-years away), and KY Cygni (5,200 light-years away). All three are 1,500 times bigger than our own Sun, and would reach out midway between Jupiter and Saturn if they were in our Solar System. These stars aren't extremely massive, though, they're only 25 times the mass of the Sun (stars have been discovered which have 150 times the mass of the Sun).

The Hubble Space Telescope is helping to confirm the potential discovery of an extrasolar planet; the companion of a dim brown dwarf located 225 light-years away. The object was first discovered in April 2004 by astronomers using the European Southern Observatory's Very Large Telescope. Astronomers think it might be a 5 Jupiter-mass planet because it's glowing too dimly to be a star. The planet and its parent star are 130% of the distance between Pluto and the Sun, so it takes 2,500 years to make one orbit. If Hubble confirms the object, this could become the first extrasolar planet ever imaged directly.

Greetings, fellow SkyWatchers! This week begins on the "dark side" as we welcome New Moon at perigee and do an in-depth study of a portion of the Eridanus/Fornax galaxy fields with targets viewable by a variety of scope sizes and skill levels. (Veteran galaxy hunters? You asked for it - you got it! I think you'll appreciate these challenges!) We will continue to track the progress of the Mercury/Venus pairing as they appear about one-third a degree apart by mid-week and head off together into the sunrise by week's end. We will greet the "Old Moon In The New Moon's Arms" and watch as Saturn reaches opposition. The Southern Hemisphere will enjoy Comet LINEAR K4 as it cruises past Lambda Pictor and those in the north will take on an incredibly old galactic cluster - M37. Not enough? Then hold on tight to your optics as the "Magnificent Machholz" not only sweeps by Algol, but does so during a time when the Demon Star "does its thing"! The Delta Cancrid meteor shower fills the exciting weekend agenda, so hope for clear skies and get thee outside...

Because here's what's up!

NASA's Spitzer Space Telescope has found a dusty ring of material orbiting nearby Vega which was probably the result of a series of protoplanets smashing into each other. Vega is the fifth brightest star in the sky, located only 25 light-years away in the constellation of Lyra. This dust is constantly being blown out by Vega's intense radiation, so it's unlikely that the star has had this much dust for its entire lifetime. Instead, this ring must have been formed recently, perhaps when a Pluto-sized object was pulverized within the last million years or so.

The very heart of the Milky Way is obscured by a thick wall of dust that optical telescopes can't peer through. But astronomers have used the dust-penetrating infrared capabilities of the 6.5 metre Magellan telescope in Chile to look past the wall, and map stars never seen before. Astronomers found thousands of stars jammed into an area only 6 light-years across. The purpose of these observations was to uncover stars which could be orbiting and feeding white dwarfs, neutron stars, or even black holes. These special binary objects are thought to be more common in the crowded centre of the Milky Way.

Scientists already considered Saturn's moon Iapetus unusual, because of its strange two-toned appearance; one hemisphere is dark, while the other is bright. But new images from Cassini show an even more unusual mystery: it has a seam. It's 20 km (12 miles) high and runs 1,300 km (808 miles) directly around Iapetus' equator. In some places, this ridge is so high it rivals Olympus Mons, which is unusual for an object which is 1/5th the mass of Mars. Researcher will have to wait until September 2007 for Cassini's next pass, when it will provide pictures 100x better resolution.

After four years of data crunching, NASA and the National Geospatial-Intelligence Agency have completed a comprehensive topographical map of 80% of the Earth's surface. Australia, New Zealand and the South Pacific were the final areas released to the public this week. Many of the smaller islands have never been properly mapped because of their remoteness, often being obscured by persistent clouds. It's these smaller islands which are at great risk to weather and long-term sea level rise, so being able to predict where water levels will go will be very helpful to mitigating future disasters like the Asian Tsunami.

NASA completed a major milestone this week as part of its work to get the space shuttle fleet flying again when the newly redesigned external fuel tank arrived at the Kennedy Space Center in Florida. The tank will eventually be mated with the space shuttle Discovery for its Return to Flight mission, STS-114. NASA and Lockheed Martin have spent almost two years redesigning the tank to make it safer. One major redesign was on the forward bipod fitting, which shed the foam that led to the destruction of Columbia last year.

Happy New Year fellow sky watchers! The New Year gives everyone a chance to make plans, resolve themselves to new and better habits and the hope that the New Year will be a good one. January also offers stargazers a chance to plan a years worth of observing. For some this may seem like a daunting task. Many observers, particularly those new to amateur astronomy, still ask ?what should I look for, what will I see?? It is in the spirit of this question that I offer a year long ?to-do list? for back yard astronomy. It is by no means an exhaustive list, but it might get you out the door and lead you to many other discoveries. The list is a mixture of upcoming events and small, at home projects that require no special equipment, just a healthy curiosity.

Astronomers from Yale have used data from the Hubble Space Telescope to develop a map of dark matter clumped inside clusters of galaxies. These clusters contain hundreds of galaxies bound together by gravity; about 90% of their mass is dark matter. The team used a technique called gravitation lensing to see how the light from distant galaxies was bent by the gravity of closer galactic clusters. Even though dark matter is invisible, its mass will still bend light like regular matter.

NASA has given a Canadian firm the green light to begin developing a robotic salvage mission that could repair and upgrade the aging Hubble Space Telescope. The agency awarded a $154 million contract to Canada-based MacDonald, Dettwiler and Associates. This is the same firm that developed the Canadarm, and contributed to the Mobile Servicing System on the International Space Station. MDA's solution is called Dextre: a two-armed robot that could perform all of the same maintenance tasks that had originally been designed for human astronauts. The move towards a robotic solution is still controversial, and NASA hasn't made the final decision on what to do with Hubble yet.

NASA's Swift observatory is only in the initial testing period, and it's already finding massive gamma ray bursts. Scientists were calibrating the telescope when it recorded a burst on December 17, three on the 19th and then one on the 20th. The team was hoping they'd see 2 bursts a week, so this greatly exceeds expectations. It could be that they were lucky, or they underestimated how often these explosions occur. The Swift team also tested the observatory's instruments by pointing it at Cygnus X-1; a well-known object that produces a signficant amount of gamma rays.

At a traditional wedding, the bride, well hidden by a veil, gracefully walks up the aisle. At the appropriate moment, the groom gently moves the veil aside so all can share in the wondrous visage of his new bride. Jeffrey Kargel provides the same service for us in his book, Mars: A Warmer Wetter Planet as he draws away the veil of mystery surrounding Mars to show us the red planet's intriguing visage. Not only does he provide a detailed analysis of shapes and features, but he also provides a description of how these likely came into being. Considering that Mars and Earth have been dancing together in their orbits for so long, it is about time that we have a book like this to get to know more of our partner.

Cassini took this image of Rhea, one of Saturn's moons, which shows the bright rays from a relatively fresh crater on its eastern limb. This image was taken on November 10, 2004, when the spacecraft was 3.6 million km (2.2 million miles) away from Rhea. Cassini will make a much closer approach to the moon on November 25, 2005.

Planetary nebulae are created when large stars shed material near the end of their lives. This material should expand in a perfect sphere, but astronomers have found many examples where the material is twisted into an unusual elliptical or bipolar shape (like an hourglass). A team of German astronomers have detected the presense of a magnetic field around the central stars in four planetary nebulae - it's these magnetic fields that could give nebulae their unusual shapes.

The Chandra X-Ray observatory took this image of an unusual star called Beta Ceti. It's only three times more massive than our own Sun, but it radiates 2,000 times more X-ray power. Astronomers believe it's putting out so much X-ray radiation because it's at an advanced stage of stellar evolution called "core helium burning". For its first billion years, Beta Ceti was converting hydrogen to helium through fusion, but it ran out of hydrogen fuel and became a red giant star. Then it started to shrink again, and temperatures rose to 100 million degrees; hot enough that it could begin fusing helium atoms together to create carbon atoms.

NASA's Spirit rover celebrated the completion of its first full year of operations on Mars yesterday, and began its second by analyzing puzzling new rocks. Spirit is currently exploring a region of the Gusev Crater called Columbia Hills. Scientists uncovered a completely new kind of rock in December, which look like they were ejected from a volcano or meteor impact. On the other side of Mars, Opportunity is examining its own heat shield, which protected its descent through the Martian atmosphere. By studying how charred the shield is, engineers hope to improve their ability to deliver future robots to Mars.

Cassini made a relatively close flyby of Iapetus on December 31, 2004, and took photographs which show Saturn's third-largest moon in unprecedented detail. Iapetus is best known for its two-toned colour; one hemisphere is dark, while the other is bright. Cassini passed within 123,400 km (76,700 miles) of the moon, which is 10 times closer than Voyager 2. One possiblity for Iapetus' dark side is that it passed through a cloud of organic material which painted one side. Another idea is that the dark material originated from inside Iapetus, and was ejected in a series of volcanic eruptions. Hopefully this, or an upcoming flyby in 2007 will give scientists enough information to understand it better.

The powerful Gemini Observatory took this image of spiral galaxy NGC 6946, which is awash in star formation. This image was taken with a special filter designed to highlight the regions of star formation. Astronomers aren't sure why this galaxy is so furiously building new stars, compared to the other galaxies in our local neighborhood. And all this starbirth leads to supernovae, which are explosions of massive stars that "live fast and die young." Just in the last century, astronomers have seen 8 supernovae explode - more than any other galaxy ever observed.

Greetings, fellow sky watchers! I trust everyone's holidays were wonderful? It's time to start a New Year and what better way than with a bit of celestial "fireworks" as the Quadrantid meteor shower begins the week! Dance along the ecliptic plane as five planets are visible in the morning skies and Moon occults Jupiter for Africa and part of Australia! Journey with me as we explore the "death" of a star in the M1 and celebrate the "birth" of a new solar system with T Tauri. We will begin exploration of Orion with the M78 and the "Flame" nebula. Who knows? This could be your lucky "Knight"! The week end becomes even more exciting as the last of the Moon occults Antares for the northwest and the "Magnificent Machholz" joins the Pleiades in a spectacular showing! As Saturn reaches the ascending node, we'll be out reaching for the stars...

Because here's what's up!

NASA's Cassini spacecraft will make its closest approach to Saturn's moon Iapetus on New Year's Eve, passing only 123,400 km (76,700 miles) away. Iapetus is best known for its strange two-toned colour, and it's also been called the "Yin Yang Moon" - one hemisphere is completely dark, and the other is white. At 1,400 km (890 miles) across, it's Saturn's third largest moon, and it was originally discovered by Jean-Dominique Cassini in 1672 who actually deduced that one side of the moon was dark, and the other bright. Cassini will make another 13 close encounters with Saturn's moons during 2005, 8 of which will be past Titan.

A few weeks ago, I let you know that Dr. Jean-Pierre Lebreton, the Huygens Project Scientist and Mission Manager from the European Space Agency, graciously agreed to answer questions from Universe Today readers and forum members about Titan and Huygens. Your response was incredible, and we got dozens of great questions - thanks to everyone who participated. The Community Support team picked their favorites and passed them along to Dr. Lebreton. We've got the answers back. So, if you want to know more, read on...

Happy Holidays, Skywatchers! This week we continue our celestial journey beginning before dawn with a close pairing of Venus and Mercury. As we wait for the later and later rise of the Moon each evening, we will visit in Aries with a fine double - Mesarthim. Returning again to the north, it's time to locate the M34 in Perseus and begin studying the open clusters of Auriga with the M36 and M38. For those in the north, discovery awaits you with the "Little Dumbbell", M76, while the south enjoys the incredible Eta Carinae. Celebrate the end of an old year and the beginning of a new one by journeying across time and space. Take the time to enjoy the singular beauty of "Hind's Crimson Star" and return again to the "Magnificent Machholz" as it climbs even higher and gets even brighter! So grab your binoculars, get out your telescopes, and hope for clear skies...

Because here's what's up!

An unmanned Progress cargo ship reached the International Space Station on Sunday, and the two-man crew got right to work unloading its cargo. Cosmonaut Salizhan Sharipov and NASA astronaut Leroy Chiao had both cut their food consumption by 10% to stretch out supplies, and had each lost a few kg during the last month. The Progress ship is carrying 2.5 tonnes of supplies, including a 15kg (33 pound) gift package for each man.

Astronomers have now ruled out the possibility that Asteroid 2004 MN4 will strike the Earth in April 2029. Scientists from the Spacewatch Observatory near Tuscon, Arizona searched back through older observations to find some images of 2004 MN4 that were captured in March, 2004. This gave them enough data to recalculate the asteroid's path, and see that it doesn't pose a threat to the planet.

NASA's Opportunity Rover has reunited itself with the heat shield that protected its entry into the Martian atmosphere almost a year ago, when it first arrived at Mars. After it was ejected, the shield crashed to the surface nearly 2 km away from Opportunity's landing spot. The rover will study both the heat shield, and its impact mark - now the freshest crater on Mars. Engineers will have an opportunity to understand how the heat shield performed during atmospheric entry, and scientists will get a chance to see what's beneath the surface of Mars.