Big news came from the Hubble Space Telescope today. Observations from the famous telescope made in ultraviolet light show a large plume of hydrogen and oxygen spewing from, Jupiter’s moon, Europa’s south polar region. Europa is one of Jupiter’s four largest moons, known as the Galilean Moons, after their discoverer Galileo Galilei in the 17th century. The plume is guessed to be water gushing from cracks in the ice that covers the entire surface of Europa. This is the first observation of geysers on Europa although it has been suspected for some time now.
Europa is roughly the same size our our moon and is covered with ice. This has been known for centuries since Galileo discovered the moon in 1610. Europa is easily visible in binoculars and small telescopes and is extremely bright. It was correctly guessed that Europa was covered in a layer of ice because it reflects a very high amount of sunlight. Ice is one of the most reflective materials, about 70% of sunlight is reflected back off the surface. The spacecraft we have sent to Jupiter such as Voyagers 1 and 2 and the Galileo probe confirmed the existence of an icy surface.
The surface of Europa is interesting because it doesn’t contain any craters or any marks of impacts like the vast majority of moons in the solar system. That means that Europa is constantly re-making its surface. The same way glaciers and tectonic plates reform the surface of Earth, giant cracks along the surface of Europa indicate that the surface is geologically active. Where there is surface tectonics there should be geological events such as volcanoes or geysers. That’s what Hubble confirmed today.
The observations from Hubble showed a massive plume of water gushing from the moon’s south polar region. The plume extends approximately 200 km (125 miles) into space. Europa has no atmosphere and much less gravity than Earth so the vapor is able to spew well beyond the surface of Europa. The water from the geyser was blasted from beneath the icy surface at a whopping 700 kilometers per hour (1,500 mph). That’s three times faster than a commercial jet! Two questions remain to be answered: How do we know the geyser is shooting out water and where does that water come from?
A Veritable Waterworld
The existence of water on Europa has actually been known for a long time. To know how this works we have to know a little bit about Europa’s orbital properties. Europa orbits Jupiter, the solar system’s largest planet. Jupiter’s gravity is so intense that it actually effects the insides of its closest moons. Europa’s orbit is slightly elliptical, meaning that it isn’t a perfect circle, an ellipse or oval-shaped orbit. Most celestial bodies have slightly elliptical orbits but Europa’s is more pronounced. When Europa is closer to Jupiter the massive gravity of the planet literally squeezes the moon and stretches the rocky core. This pressure and friction creates heat under the icy surface and has created a subsurface ocean on Europa. It is guessed that Europa actually contains more water than Earth as Europa’s ocean is global, there are no landmasses. NASA and the European Space Agency hope to eventually send a probe to Europa to explore this massive subsurface ocean because where water exists the possibility of life also exists.
The Giant Plume
We’ve answered where the water comes from, but how are scientists sure it is indeed water that was spewed from the surface and how does such a tiny moon have geysers that powerful? Hubble doesn’t just do visible light observations. The telescope is also equipped with a camera that can image in ultraviolet light. The actual images taken by Hubble don’t show what we think of as a geyser like Old Faithful in Yellowstone National Park. What Hubble observed was actually individual hydrogen and oxygen atoms in the plume. Since Europa has no atmosphere the hydrogen and oxygen atoms were in space. Jupiter, like Earth, generates an magnetic field in its solid metal core. When the water from the geyser interacts with the electrons from Jupiter the water separates into its constituent hydrogen and oxygen atoms which glow in ultraviolet light. That’s the best possible explanation for why Hubble observed these two individual atoms.
But where did the geyser come from? Well as we saw earlier about Europa’s elliptical orbit, the moon is closer at some points and further away at others. As Europa moves closer to Jupiter it is squeezed and crunched by Jupiter’s immense gravity. Then as Europa moves further away from Jupiter cracks in the ice open up and allow the subsurface water to rise up and spew out. As it so happens, Hubble recorded these observations while Europa was moving away from Jupiter so it makes sense that the cracks in the icy surface were opened up.
Teeming With Life?
The prospect of life swimming in Europa’s ocean has long been intriguing. The discovery of geysers on Europa make the question even more worth exploring. As we see from geysers on Earth, a lot of power in needed to blast material out from under the surface. On Earth this comes from heat and pressure that builds up beneath cracks in the Earth’s crust. When the heat and pressure becomes too great water and gases burst forth in a steaming awesome display of geological activity.
One of the theories of how life began involves water and heat in the prehistoric oceans of Earth. Hydrothermal vents on the ocean floor mix heat and amino acids to create the first organic materials. To this day life thrives around hydrothermal vents despite the extremely alien conditions. We know there is heat in Europa’s oceans due to the gravitational heating of the core from Jupiter and there’s water which is a universal solvent. Could the mixing of amino acids, water, and heat have occurred on Europa as well? The prospect is certainly intriguing and worthy of further exploration. Curiosity is one of humanity’s definite traits so hopefully in a decade or two we will have a spacecraft on its way to Europa to explore the subsurface ocean and attempt to find evidence of life. Imagine fish (or something totally alien) swimming around on the moon of a distant planet! How that would change our views of life and its frequency throughout our galaxy!
It’s crazy how easy it is to get distracted from writing. All it takes is one day to go by without writing, then you go a week without writing. A week turns int two weeks, which becomes a month. Before you know it you haven’t posted anything on your blog since August! I’ve done many things worthy of writing about since August including trying my hand at astrophotography for the first time, attended to two star parties, almost been killed by someone spotlighting deer while observing in southern Maryland, and failed to observe comet ISON several times before its unfortunate demise on Thanksgiving. There has also been loads of astronomy news since my last post as well.
I’m mad at myself for slacking off so much over the last five plus months but I’m back and better than before! To make up for the absence of posts since the summer I will share with you all the (best) astrophotos I managed to take during the summer. Back in July I borrowed 80mm refractor telescope and an German equatorial mount from my astronomy club to assist with a star party I was planning on hosting for my friends. The star party never worked out due to weather and other factors but I got to try my hand at proper astrophotography for the first time. I had absolutely no prior experience using an EQ mount so this was all very new to me. The key part of deep sky photography is aligning the mount with the celestial north pole, or CNP. Since long exposures are needed to collect the light from faint deep sky objects, what you’re imaging moves across the sky while your camera’s shutter is open. To compensate for the Earth’s rotation and keep the stars “still” in your telescope the mount you’re using has to be aligned with the celestial north pole, or the Earth’s polar axis. For people in the northern hemisphere the CNP is about 3/4 of a degree away from the star Polaris in Ursa Minor. That’s why Polaris is known as the North Star, or the Pole Star. Everything else in the sky appears to rotate clockwise around Polaris.
I was never good at polar aligning the mount so that severely limited what I was able to image. I was stuck with exposures of 30-40 seconds. Nevertheless, that’s still good enough for a couple familiar objects such as the Andromeda Galaxy, the Orion Nebula, and the Dumbbell Nebula. I had assistance from the Reddit community of astrophotographers. Their collective knowledge and wisdom was invaluable in my novice attempts to photography things many light years away.
The first object I imaged was the Andromeda Galaxy. Known by astronomers as Messier 31, on Charles Messier’s famous list of faux comets. M31 is best known as the Milky Way’s twin galaxy. The galaxy has roughly the same mass as the Milky Way but is 2.5 million light years away. Andromeda is the closest spiral galaxy to the Milky Way and is so bright it can be seen with the naked eye from darker skies. A small telescope reveals a giant bright and elongated fuzzy patch. Larger telescopes under dark skies may even reveal dust lanes on the north side of the galaxy. I chose M31 as my first target because of its brightness which would require shorter exposures.
Once the mount as telescope was set up and the mount polar aligned (as best I could do) I attached my camera to the focuser and began shooting away. The image below is a stack of 30 :40 images. I used Deep Sky Stacker to combine the images and Photoshop to process it. I did a poor job of framing the image so the bottom part of the galaxy is cut off. I hope to revisit M31 later on and do a better job. There are actually three different galaxies visible in the image! The obvious one is M31 but fuzzy oval located top left of M31 is another galaxy called M110 and at bottom right is M32. Both are elliptical galaxies, meaning they have no spiral structure, and are satellite galaxies of M31. They are both gravitationally bound to M31 and are, like M31, part of the Local Group of galaxies. These three galaxies are all next-door neighbors to the Milky Way.
The next object I imaged was M27, known as the Dumbbell Nebula. The Dumbbell Nebula is what astronomers call a planetary nebula. They actually have nothing to do with planets despite their name. A planetary nebula is what happens to massive stars right before they die. As the star ages it begins to shed its layers of gas as the nuclear fission in its core slows down. Our own sun will eventually do this as it begins the final stage of its life. M27 is the most well-known and studied planetary nebulae because of its brightness and close distance to Earth. For this target I used the same exposure settings, 30×40 sec and stacked in DSS.
One final image I’ll share is perhaps my favorite, for two reasons. One because of its aesthetic beauty and because of its difficulty to process in Photoshop. You’ll no doubt recognize the Great Orion Nebula. This giant cloud of gas and dust is where stars are formed. In fact, the Hubble Space Telescope has imaged many newborn stars within the nebula over the past twenty years. Known as Messier 42, the Orion Nebula is visible to the naked eye even in light polluted skies. The nebula is located in the sword of Orion that hangs from the Hunter’s belt. The nebula itself appears as the middle star is the sword but closer inspection with binoculars reveals something more than a star, but a bright greyish glow which is actually the nebula.
Just like as in the M31 image, there are actually three separate nebulae present in this image. The largest, and brightest is M42, an emissions nebula and its intricate knots of gas and dust in brilliant colors. Next to it is M43, also an emission nebula like M42. Emission nebula are named as such because they emit their own light from ionized gas that glows in an array of colors. The third nebula is the one in the upper left of the image. It is called NGC 1977, or the “Running Man Nebula.” NGC 1977 is what is called a reflection nebula, meaning the gas and dust doesn’t emit any light of its own, but rather reflects the light of stars inside or around the nebula. See if you can notice the running man pattern.
All these images were taken with a Nikon D3100 with a SkyWatcher ED80 refractor mounted on an Orion SkyView Pro EQ mount. The mount and scope were borrowed from the Harford County Astronomical Society (HCAS). My thanks to the club! Check out their website at http://www.harfordastro.org.
That’s it for now. I hope to be able to share more deep sky objects in the future. Until then clear skies and keep looking up!
After a few months of inactivity I’ve developed an idea that will keep me busy blogging. It’s been cloudy for so much of the summer so I haven’t been able to do much observing. My attention, therefore, has turned to other activities related to astronomy that I can pursue when the weather is not ideal for observing. If you’ve read any of my previous articles on this site you’ve probably read about light pollution. Maybe you’ve heard of it elsewhere or perhaps you’ve never even considered the possibility of light being a pollutant. While electric lighting is a marvel of the industrial age and a wonderful aide to modern life it also, like many good things, has a darker side.
From the beginning of life on Earth approximately 4 billion years ago all of Earth’s creature, including humans, have lived in an unending cycle of light and dark. Bright sun-drenched days give way to the darkness of night and the majesty of a star-strewn sky with its backbone the Milky Way arching across from horizon to horizon. Life has evolved according to that cycle and it has flourished. It wasn’t until just over 100 years ago that we began introducing large quantities of artificial light into the environment. This artificial light disrupts the light-dark cycle (also known as the circadian clock) that life has depended on for billions of years. It has endangered species like insects, turtle, hundreds of species of birds, and all manner of nocturnal creatures. Artificial light is also a known contributor to many human diseases such as obesity, insomnia, diabetes, and hormonal cancers. Besides the biological effects of artificial light, it is also a massive waste of energy. Every year in the United States alone, poorly designed or over-used light that shines up into the sky wastes $2.2 billion!
Last, but certainly not least, artificial light has destroyed the night sky that humans have loved for thousands of years. When the lights from un-shielded fixtures shine up into the sky the light scatters when it hits particles in the air. The result is called skyglow. You can clearly see the effects of skyglow when you look towards a city or town at night from a distance. The yellow, orange, or pink glow in the sky is the sum of all the light from all the street lights, parking lot lights, stadium lights, residential lights, etc…and their light scattered in the air. The dome of light obliterates all but the brightest stars and the Milky Way is a thing of the past. Depending on the size of the city, skyglow is noticeable from as far as 100 miles away as a dome on the horizon.
Light pollution has severe negative consequences on my pursuit of my hobby of astronomy as I have to drive considerably far from my home to view under dark enough skies. I currently drive 33 miles from my home in north Baltimore to reach my observing site in Fawn Grove, PA and even there the effects of light pollution are quite pronounced and the Milky Way is barely visible on clear, moonless nights. To reach a location almost totally unaffected by light pollution I’d have to drive five hours north to Cherry Springs State Park near Coudersport, PA.
What I’ve decided to do over the next couple months (or however long it takes) is to compile a photo essay of sorts that chronicles the effects of light pollution throughout the Maryland and Pennsylvania area. My goal is to photograph constellations, horizons, skylines, and light fixtures everywhere to make known to my readers the harmful effects light pollution has on the night sky and astronomy. I will visit many locations throughout Maryland from the Inner Harbor in Baltimore, to a swamp on Maryland’s Eastern Shore, to rural York County, PA, an international dark sky park, and many places in between. I hope that this project will open some eyes and convince people of the reality of light pollution and the truth that it is something that we CAN fix.
In the United States today, eight out of ten people will never see the Milky Way in their lifetime because of light pollution. It doesn’t have to be that way though. Through public education and teamwork with local governments we can reverse the harmful effects of light pollution and preserve the night sky and its splendor for future generations.
Memorial Day weekend was very productive for me. A couple weeks ago I purchased my first DSLR camera, a Nikon D3100 and I’ve been itching to start photographing the night sky. My first big target was the planetary alignment of Venus, Jupiter, and Mercury over the weekend which did not disappoint. I was able to shoot the planets on both Saturday and Sunday nights under perfectly clear skies. This was a relatively easy target for my first foray into the world of astrophotography.
On Saturday night I took my camera and tripod up to my dark sky site in Fawn Grove, Pennsylvania. I arrived around 8:30 just as the sun was setting. While darkness was gathering I set up the camera and punched in the initial settings and waited for Jupiter to appear. Venus was already brilliant approximately ten degrees above the horizon by 8:45. Jupiter appeared minutes later, followed by Mercury visible to the naked eye around 9:00. I played with the aperture and shutter speed until I captured an image I really liked. I ended up with a focal ratio of f/8 and a 1.6 second exposure at ISO 100. The final result once I played with it in Photoshop was very nice, as far as my inexperienced self is concerned. That’s Venus at the bottom of the triangle, Jupiter at upper left, and tiny Mercury at upper right.
This was just practice for Sunday of course. Sunday’s alignment was the one that captured everyone’s attention. The almost equilateral triangle of planets is something you won’t easily forget if you saw it for yourself. If you missed it you’re in luck because photographers all over the world captured the stunning alignment. I’m relatively happy with how mine came out. The only drawback is that the planets are slightly out of focus. I should have been paying closer attention to that. However, them being out of focus kind of allowed more color to come out, especially in Mercury. I worked with the same camera settings as Saturday night. After some adjustments in Photoshop this was my final result.
After the planetary imaging session I was feeling lucky so I tried my hand at some wide-angle constellation shots. I turned the camera towards Ursa Major and took 200×10″ frames and went to stack them in Deep Sky Stacker only to find that my images were out of focus and DSS couldn’t recognize any stars. Not so lucky I guess. I was determined to get it right so I went back outside around 11:30 and decided to shoot the constellation Lyra and it’s bright star Vega. This time I took 200×1.6″ frames at f/4, ISO 3200 and went in to stack them in DSS. The result was much, much better. About 2 hours later I had a decent image with which to work with. I gave it several editing passes in Photoshop before I produced an image I was happy with. Not only are all five of Lyra’s main stars visible, the double star Epsilon Lyrae showed up which really made me proud. This is my first constellation shot so I guess it’s the small things that bring me joy.
Overall, it was a very productive weekend. I learned a lot about how important it is to really nail the focus before shooting anything. Trial and error is how you improve in this hobby. I’m hoping to get a few more practice shots under my belt before taking the camera up to Cherry Springs State Park in a week and a half to shoot under a real dark sky. As I produce more images I will post them here so I hope you stick around and if you have any suggestions or critiques to help improve my technique I’d gladly appreciate it.
I think it’s a safe assumption to say that whenever anyone gets into astronomy their greatest desire is to be able to take pictures of what they observe. The saying that a picture is worth a thousand words is certainly true of astrophotography. There is certainly a great joy in observing the universe with your own eyes at the eyepiece and that should unequivocally be any amateur’s first love. Given the mass-availability of photography equipment and astro-imaging software and techniques it is no surprise that astrophotography has risen to such popularity in the 21st century. All someone has to do is watch a couple of tutorial videos on YouTube and you have a pretty good sense of what equipment and software you need and it’s easy to practice the techniques employed by more experienced photographers.
I’ve decided to jump on the astrophotography train myself. Mind you, I don’t own a fancy equatorial mount for my telescope or even a DSLR camera for that matter so I have to try a slightly different method to get images. By far the best and easiest way to do astrophotography with a Dobsonian mounted telescope is with a webcam. This method is really only useful for planets, the moon, and sun given that images of deep-sky objects requires long exposures that would produce star trails if not tracked. However, it was extremely rewarding producing my first planetary image.
I’m not going to go into detail on how I captured my images because that would just be an incredibly long post. Instead, I just want to share the equipment and software I used to give you a sense of how easy (and inexpensive) it is.
My telescope is an Orion XT10i Dobsonian which already provides very nice planetary images in the eyepiece. Images are always sharp and bright when in focus. For this experiment I purchased a Microsoft HD Lifecam from my nearby Staples office supply store. I went with the Lifecam because it has a body that is perfectly designed to fit inside any 1.25″ focuser tube. The Lifecam can also shoot 1280×720 720p video at 30 fps (after some tinkering) which is something special for a webcam. I followed the instructions provided by Gary Honis, who is the authority on all things webcam photography related, on his website, found here. I didn’t use the 1.25″ barrel extenders like he did, rather I used a film canister. The film canister seems to work just fine and it fits snugly into the focuser.
To capture the video I downloaded a piece of software called AMCap which is freeware video capture. It’s available for a free download but a donation is asked for, but not required. Also, a jpeg video codec is needed to capture the raw video in .avi format. Any jpeg codec you can find will probably work but Gary recommends a particular one on his software tests page. Finally, I used Registax 6 to stack the images from the raw .avi video and touched it up a bit in Photoshop CS6 an voila! a nice, crisp, clean image of Saturn.
This method is very easy to do for anyone without a tracking mount and what’s best is that it only cost me $35 plus shipping and handling. If you have a Dobsonian telescope this method is definitely for you.
I’ve always been a conservationist and an eco-minded person since my days in Boy Scouts. We learned that nature is should be respected and cared for and as much as possible we should live in harmony with our surroundings. However, when you’re able to see pictures of the Earth from space your whole perspective changes. I’m sure most people are familiar with the famous “Earthrise” photograph taken by Apollo 8 astronaut William Anders in 1968. ”Earthrise” gave a whole new perspective of our home planet and gave realization to the fact that our planet is just a fragile little island floating in an unimaginably huge universe. Imagine being in the position of Anders or any of the Apollo astronauts as they saw the Earth rise over the lunar surface and realized that everything they’ve ever experienced, everyone they’ve ever known, all their prior life was 250,000 miles away on that small blue rock.
Few people have had the privilege to see the Earth from space, whether from low orbit or during a lunar mission but we’ve been able to vicariously experience it through the photos and films they’ve brought back that have left us stunned. One such striking video was recently compiled by NASA’s MESSENGER probe as it left the Earth on its way to Mercury. The probe had a camera pointed back towards the Earth as it left it behind and the stitched together frames produced in image of stunning beauty and inspiration. As the Earth slowly fades away into the blackness of space we realize our true place in the universe. We are but minnows swimming in a vast, vast ocean.
Even with the potential of planetary travel and colonization in the distant future we must still place immeasurable value on our home planet. The Earth has been so good to us for millions of years and will continue to do such if we take proper care of it. As a whole, the human race is awakening from a slumber of environmental torment. From the mid-to-late 1800′s and the dawn of industrialism we have polluted the planet to a sickening degree. We’ve deforested much of the rain forests and polluted the water we drink and the air we breathe. For over a century we were largely oblivious to the damage we were doing to our fragile environment. But now we’re waking up to the consequences of our actions. It is not too late to reverse the damage we’ve done to our planet because she is a resilient creature. But that should not give us a license to continue to damage her and squander the beauty and riches of our island home.
Even if we travel to hundreds of planets in the future we may never find one quite like Earth (if we find any like it at all). We were placed here on Earth by divine decree and it is that same decree that should guide our actions going forward to restore and protect our pale blue dot, our fragile island home because it’s all we have.
Spring is finally in full swing and if you’re like me observing season is about to kick off again. I hate observing in the cold so when April rolls around it’s usually an indicator that better nights are coming…unless you live on the East Coast where it’s been unseasonably cold and cloudy for the last month. April is also exciting because it is Global Astronomy Month. Each year since 2009 Astronomer Without Borders has designated April as Global Astronomy Month to raise awareness for the study of astronomy both professionally and amateur. In my opinion, the biggest part of GAM is International Dark Sky Week. Beginning tomorrow April 5 and continuing through April 11, Astronomers Without Borders and the International Dark Sky Association are teaming up to raise awareness of the issue of light pollution. If you’ve read this blog before you’re probably familiar with the light pollution as I write about it quite frequently.
Because of light pollution, the artificial brightening of the night sky, less than a third of Earth’s population lives under natural, starry skies. Fifty percent of Americans and 75% of Europeans have to travel at least an hour from their homes to see a natural star-filled sky unaffected by light pollution. From my home in Maryland I have to travel 4.5 hours to reach the only truly dark sky spot around, Cherry Springs State Park in Potter County, Pennsylvania. I am willing to make this pilgrimage once or twice a year but there should be somewhere closer to observe from that has a quality dark sky. The reality is, however, that these places are slowly dwindling in number. Artificial light, the scourge of the night sky, is slowly but surely conquering the beauty of the natural night sky.
Light pollution comes from poorly designed artificial light sources we use at night. Most of these light sources are from street lights that are unshielded so that light escapes upwards into the air which causes the light particles to scatter and create that familiar sky glow effect. Other problems are that we often use wattage that is too high for the task we’re trying to accomplish. If you’re using too bright of a light the light actually reflects off the ground and bounces back up into the sky to contribute to the sky glow.
You’ve also probably noticed the annoying glare that unshielded lights cause while driving. Glare comes from the bright ball of light generated by a typical drop lens or acorn style street light. See the example below for a typical “glare bomb”. The glare created by these lights can not only be annoying while driving, they can also be dangerous for people with poorer eyesight such as seniors or people with sight disorders. They are also so bright that they can mask important things like road signs and signals along with pedestrians and animals in the road.
Light trespass is also an result of poor lighting design. Light trespass occurs when a light from a neighbor or nearby building shines, or trespasses, on your property. For example, a stray light that shines into your bedroom at night that causes you to get inadequate sleep. To make a long story short, the lighting used should fit the requirements of the task it is trying to accomplish, no more, no less. We all agree that artificial light helps our society. But since when did extravagant over illumination become acceptable. Not only does light pollution affect the night sky, it is also a HUGE money waster! Every year over-illumination in the United States alone costs the same as approximately 2 billion barrels of petroleum and consumes unnecessary fossil fuels that are not replenish-able. Imagine how the cost of a gallon of gas could decrease if we didn’t over-illuminate our homes, businesses, and roads!
Fortunately, the solution for light pollution is relatively simple. Taking the time to assess your lighting needs and using the proper wattage and shielded fixtures will go a long way in reducing the amount of artificial light we send up into the night sky. Using shielded fixtures ensures that the light only goes where it is needed: the ground. This also allows for a lower watt bulb to be used and that in turn reduces the amount of light reflected back off the ground. Motion sensor are also useful to turn the light on only when there is movement.
Talking to neighbors about their lighting in a polite but concerned way is a great way to introduce the topic to them. Writing to legislators can be effective as well. There have been a number of municipalities that have incorporated lighting regulations into state, county, or local code in recent years. There is a bill in Maryland that is currently in the General Assembly that would require all new light fixtures purchased by state agencies to be fully shielded. The biggest hurdle we have to overcome is simply making people aware that there is a problem. Many people don’t even think about the light they see at night or how their lights are contributing to the pinkish glow we know all too well. In order to reverse the effects of light pollution we must use word of mouth to let people know that light pollution is real and it is diminishing the beauty of our night sky and wasting money in the process.
If you’d like to learn more about the issue of light pollution please read some of the other posts I’ve written on this blog and visit the International Dark Sky Association’s website www.darksky.org. Together we can put a cap on light pollution and restore the beauty of a star-filled sky!
A new space milestone has just occurred, or occurred around August 2012. The Voyager 1 space probe that was launched on September 5, 1977 has finally left the solar system. Thirty five years after its launch the audacious probe enters a new stage in its mission, exploring the region of space outside of the Sun’s influence.
The Sun’s influence in space extends way beyond the orbit of Neptune. We know that beyond the inner planets lies the Kuiper Belt which is home to Pluto and many, many other dwarf planets. Finally at about 18 billion kilometers from the Sun and four times the distance between the Sun and Neptune, is a region known as the heliopause. The heliopause is the region where the solar wind from the Sun collides with the interstellar medium, a collection of particles which is the collection of gas, dust, and cosmic rays. The solar particles are so dilute once it reaches the interstellar medium that the heliopause is considered the end of the Sun’s influence (although its gravity extends well beyond the heliopause to the Oort Cloud).
A new paper that has been published confirms the conclusions that were drawn about the solar wind particles back in December. Data from the probe showed that the number of subatomic particles coming from the Sun dropped dramatically sometime around August 2012 while the number of cosmic rays from the interstellar medium spiked. While it’s not exactly new news, it still is exciting to think about. There is now a man-made object outside of the solar system and is still able to communicate with us 18 billion kilometers away.
Eventually the plutonium inside of Voyager will stop producing electricity and communications will cease. At that point, the probe will continue to sail in the direction of the galactic center. There is an estimated 10-15 years of power left on the probe so we need to enjoy it while it lasts. It will be a long time before human travelers can journey this far from our home, but we’ll do it one day.
With the mid-Atlantic region being covered by winter storm ‘Saturn’ (not a fan of naming winter storms), comet C2011/L4 PANSTARRS is about to make its debut in the northern hemisphere. Observers in the southern hemisphere have been enjoying PANSTARRS for about a month already and it finally brightened enough to be a naked-eye object in the last week or so. While the usual naked-eye threshold is between magnitude +5 and +6 depending on your eyesight and sky conditions, comets aren’t point sources of light like stars and planets and their light is spread out over a larger surface are with respect to the entire sky so their brightness in magnitude can be a little deceiving. Right now PANSTARRS is hovering right around magnitude +2 which puts it theoretically as bright as the brightest stars in Ursa Major, the Big Dipper. For us in the northern hemisphere though, it likely won’t appear as brilliant as it is in the southern hemisphere because of it’s proximity to the sun. The comet is expected to make its northern debut tomorrow, March 7th after sunset. The problem for us is that it is approaching its perihelion, its closest distance to the sun, so it will only be visible during twilight. Picking PANSTARRS out might be difficult and it might only appear to the naked-eye as a small fuzzy ball barely creeping over the western horizon.
That being said, binoculars will be a great aide to those looking to spot PANSTARRS early on. The comet won’t get much higher than 10° above the western horizon. Ten degrees is approximately the size of your clenched fist held at arms length. In order to spot PANSTARRS in its first couple of days in the north you’ll have to find a viewing location that has an unobstructed view of the western horizon that is reasonably dark. Getting away from street lights and house lights is key as they both create a glare that makes it difficult to see and limits your eyes’ ability to adapt to the growing darkness. A rooftop that can be safely accessed might provide a good vantage point to spot the comet.
In a simple pair of 10′x50′ binoculars you should be able to see the dust tail that stretches several degrees beyond the comet’s nucleus. Whether or not an ion tail produced by the solar wind will be visible remains to be seen. As March wears on the comet will steadily rise in the western sky each night as it moves further away from the sun. Again it won’t get very high in the sky but at least towards mid-March you should be able to view it in reasonable darkness until about 7 pm. I’ll be away on a retreat this weekend in a semi-dark region at the top of the Chesapeake Bay so I hope to be able to snap a few pictures of PANSTARRS. I will certainly post anything that is decent.
For now, as winter storm ‘Saturn’ dumps mostly rain on me, I had to settle for this amazing timelapse video of comets Lemmon and PANSTARRS in the sky together. This was taken by Australian astrophotographer and videographer Alex Cheney. It is quite a rare sight to be able to see two comets in the same sky together! I swear those southern hemisphere dwellers get to have all the fun!
I’m sure you’ve heard the reports of the meteorite that entered the Earth’s atmosphere over Chelyabinsk, Russia this morning. For me it was a really great way to wake up and begin the day! Not 15 minutes after waking up and taking a shower I checked my Facebook and saw Phit Plait’s article on Bad Astronomy. Man oh man were those videos cool! It’s been a while since we had a daytime fireball like this. Although it’s being reported that hundreds of people have been injured by shattered glass and such, no serious injuries were reported.
The fireball appeared around 9:30 am local time in Chelyabinsk, Russia which is a city near the Ural Mountains, about 1500 km east of Moscow. It is estimated that the meteorite weighed about 10 tons, or 20,000 pounds. Upon entering the atmosphere the space rock began to break apart as seen in the train (the smoke trail) where it forms two columns of smoke. One video included below shows someone driving and captures some amazing footage of the fireball at the moment of entry. The meteorite blazes almost as bright as the sun while it glows white-hot from the friction of the atmosphere! Although it broke apart upon entry reports have come in that small fragments did indeed impact the surface. Mostly raining down as relatively harmless small chunks, several impact areas have been proposed.
By far the coolest part of the “impact” is the shock wave felt by residents that was caused by the meteorite breaking the sound barrier several times over. People hundreds of miles away from where entry occurred could hear the sonic boom. In Chelyabinsk, many windows were shattered and car alarms blared from the shock wave. I can imagine how startled and confused the residents might have felt seeing the giant train and hearing sonic booms like artillery fire. If I didn’t know anything about space and astronomy I’d probably assume that North Korea was attacking!
In case you haven’t already had this confirmed by dozens of media members and scientists, this is NOT related to the close shave we’re about to have with asteroid 2012 DA14 . The meteorite entered the atmosphere too early and was travelling the wrong direction to be a fragment of the asteroid. But it is a very cool coincidence that these two events would happen on the same day! That’s the nature of meteors and space, they can be totally unpredictable. I think this is further proof that we need to be able to detect things like this before they happen in case a much larger and more deadly meteorite were to impact us. Maybe it’s not a coincidence that both events occurred today. This Russian fireball and the close approach will hopefully serve as a wake-up call that more extensive near Earth object detection systems are needed to prevent casualties from impacts.
Anyway, enough rambling from me. Here’s some of the videos posted on YouTube from eyewitnesses. They’re pretty cool!
Car dashboard camera capture the fireball as it enters the atmosphere
I love this video because you not only hear the sonic boom, but you see the person’s reaction to the boom as almost jumps out of his pants!
Another longer video of a city street where you can hear glass shattering from the sonic boom.