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!
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.
Twenty-twelve was a fascinating year for myself, astronomy, and science. There were many scientific milestones reached and important events during the last twelve months, most notably, the we survived the bedlam that was the Mayan apocalypse. I thought I’d take some time to compile the best moments from 2012 in astronomy and space science and look ahead to 2013 hi-lighting the known astronomical events coming up.
First on the list is the impressive conjunction of Venus and Jupiter from March 15th. On the date famous for the murder of Julius Caesar we were treated to two Roman gods forming a conspiracy of their own in the sky. Venus and Jupiter, the two brightest planets in the solar system respectively, passed extremely close to each other (from Earth’s perspective), just 3 degrees apart.
Venus-Jupiter conjunctions are fairly common, occurring roughly every two years. The next conjunction will be on May 28, 2013 and will be even more eye-catching when the two planets pass just one degree from one another. Even more spectacular will be the conjunction in 2014 when the two pass only one-fourth of a degree from each other! To put that in perspective, the width of the full moon is about one-half a degree in apparent size, so the 2014 conjunction will place the planets half a moon width apart! I hate to build you up for these two conjunctions though, because neither will be visible from the Northern hemisphere. If you can wait 53 years, until 2065, you’ll get to see the best of all planetary conjunctions: a transit, when Venus passes in front of Jupiter in its orbit. I may be alive but I’ll be quite an old man by then.
The next highlight from 2012 is something, if you saw it, you’ll likely never forget…the transit of Venus. While my own luck observing the transit was less than optimal, I did get to view it briefly and it was amazing. On June 5th, 2012 Venus transited, or passed in front of the sun appearing as a small black disk silhouetted against the fiery inferno of the sun. There were some truly remarkable pictures of the transit taken by professionals and amateurs alike. What made this event so special was the rarity of it and its historical and scientific significance in past centuries. A transit of Venus takes place in pairs every 121 years then 105 years to form a cycle of 243 years. Venus crosses in front of the sun once a year in its orbit but it’s only during these cycle years that it can actually be seen from Earth due to the two planets orbits being slightly inclined.
Venus transits have been historically significant to the world of science for centuries. The first transit to be observed with a telescope was in 1639. British scientist Jeremiah Horrocks used the transit that year to make a much more accurate calculation of the Earth’s distance from the sun using angles of parallax and geometry. The 1769 transit was led to the discovery of an atmosphere on Venus. Legendary explorer Captain James Cook observed the transit that same year in Tahiti at the still named “Point of Venus”.
The next event on the list is the occultation of the moon and Jupiter on July 15th, 2012. Only observers in Europe, the Middle East, and northern Africa were able to view this majestic event but the images produced from it were spectacular.
The next event on my list is the one that I was looking forward to the most. Curiosity. I had been eagerly anticipating Curiosity’s landing on Mars for over a year and on August 5th it finally happened. Due mostly to the unprecedented entry, landing, and descent plan Curiosity was intriguing from the word Go! The sky crane and powered descent was daring and risky but it proved a massive success for NASA. Not to mention the fact that Curiosity is the most scientifically advanced planetary rover yet. The rover is practically a fully functioning mobile chemistry laboratory. Within days of its landing Curiosity sent back some of the most stunning and detailed images of the Martian surface we’ve ever seen.
The final two events on my list of memorable astronomical events of 2012 both happened in the month of December. First off is the mighty Geminid meteor shower of three weeks ago. The peak of the shower combined with a new moon allowed for some excellent viewing. The expected rate was all the way up to 120 per hour! I went out for about one hour between 10:30 and 11:30 under moderately light polluted skies and was able to count 55 meteors. I was quite impressed with the shower which included several fireball meteors with long, smokey trails.
I suppose the last event can’t really be confined to the month of December 2012. It actually spans over a length of several years but it came to a conclusion just a couple days ago. Of course I’m talking about the apocalypse! You might have called it Judgment Day, the Rapture, or simply the winter solstice, but there was an inordinate amount of hype surrounding the long-dreaded end of the Maya calendar. This event in particular is in reference to the way people with degrees in physics, astronomy, geology, cosmology, ontology, biology, paleontology, gynecology, urology, you name it, refuted the claims of doomsday made by people who are less intelligent. Two people/organizations come to mind when I think of leading the fight against stupidity: NASA and astrophysicist Neil deGrasse Tyson. Turns out people were actually believing the convoluted claims of doomsday 2012 and the world was indeed in danger…from stupidity. So hats off to you NDT and NASA for saving the world!
So that wraps up my 2012 rewind. This past year has truly been remarkable for astronomy and science. 2013 promises to be just as exciting. Stay tuned over the next day or two as I’ll preview the two excellent comets coming up in the next year.
I saw this amazing video on Bad Astronomy today and I loved it so much that I couldn’t resist sharing it. This video uses raw footage from the Cassini and Voyager missions to Jupiter and Saturn to illustrate the beauty of the two gas giant planets. The footage was compiled and edited by Vimeo user Sander van den Berg and the effect is stunning! By looking at images of the planets online or even through a telescope it can become easy to think of them as mere static worlds, like jewels in the sky. The wonderful reality is that these worlds are vividly alive and active! From massive storms the size of Earth on Jupiter to billions of ice particles racing around Saturn to form its rings, there is an orchestra of motion at the very heart of each planet. This short movie captures that masterpiece in a way that reminds you of the grandeur of the first time you saw a picture of a planet in grade school and restores that “Wow!” factor that can become less enthralling over time. The movie is simply called “Outer Space” and I think that simple title captures the essence of what’s happening in the footage. Enjoy!
Click here to view the video and read more about it on Vimeo.
The sky is always stunning to look at no matter what day it is, but this week promises some pretty cool activity for stargazers. The emphasis this week is on the solar system. To begin with, the pairing of Jupiter and Venus in the west has been stunning for several days now and is approaching the two planets are approaching their closest distance. Tonight (Monday) they will be 3.1° apart (roughly two finger widths at arm’s length, your clenched fist is about 10°). The two planets will be just 3.0° apart on Tuesday night as Venus and Jupiter begin to switch orientations. This conjunction promises a stellar view for binocular viewers and some telescope viewers at lower power.
Next up is Saturn which rises just before 10pm (EDT). Always a stunning sight no matter what time of year, but Saturn’s rings are tilted just about at the optimal angle for viewing from Earth. Over the next couple months the rings will start to flatten out until they will be seen edge-on. Also, Saturn, the moon, and the star Spica will dazzle in the sky around midnight tonight and Tuesday.
Mars is currently trekking its way through the constellation Leo this month. Each day it is getting closer to Regulus, the brightest star in Leo and the foot of the lion. Mars is just past its closest distance from Earth and is quite a pleasing sight in a larger telescope at its highest point from 11pm to 1am.
Since the moon is rising late this week we have another chance to view comet Garradd as it zooms through the inner solar system. Garradd is still at magnitude 6.0-7.0 so you likely still need to drive away from the city lights a bit to see it with a telescope. The comet is currently hanging out near the bowl of Ursa Minor and λ Draconis on Friday night.
On Sunday night I went outside in my driveway and spent a good while taking in the beauty of the full moon with my binoculars. It was a perfectly clear night and I had an amazing view of the moon for over an hour! The only drawback was that it was almost at zenith so my arms and neck needed frequent breaks. I am not equipped at all for astrophotography but I figured I’d give it a shot. All I had was my iPhone and its tiny lens so snapping a picture of the moon was not an option through my binoculars because there was simply too much light for my phone to handle. So I focused my attention to Jupiter which was hanging low in the East sky around midnight. I am simply in love with the sight of Jupiter’s moons through my 15×70’s so I decided to try it out with my phone. Unfortunately with binoculars you can never get a complete image because you can only hold the phone up to one of the eyepieces. Although the size of the planet is reduced and the moons aren’t visible (far too faint for my phone’s camera) I’m relatively please with how it turned out! Take a look:
So there it is! Obviously if you compare that to any other amateur’s pictures of Jupiter this is the worst, but I’m proud of it nonetheless! It’s still amazing that something that is 816 million kilometers away and yet we can see it with our naked eyes, and even better with equipment. So that’s that. I hope that brought you at least mild enjoyment. Until next time, remember Psalm 97:6, “The heavens proclaim His righteousness, and all the peoples see His glory“
If you live in Maryland and are looking to do some stargazing tonight is a GREAT night for it! We’re looking at an overnight low of 40° which is extraordinarily mild for this time of year! On top of that it’s a clear night. The only draw back is that the moon is almost full tonight, but you’ll get some incredible views of the moon if you have a nice pair of binoculars! Jupiter is still high in the sky along with the Crab Nebula to the lower right of the moon. Those three objects are all relatively close to one another and should provide some excellent viewing. As always during the winter the Orion constellation and its brilliant nebula are visible until a couple hours before dawn. This will be, hands down, a great night for some Ball So Hard stargazing! To God be the glory!
When I got my new Celestron Sky Master binos for Christmas the first thing I absolutely couldn’t wait to see was the moons of Jupiter. I took my new toy out to the field next to my house and set up the tripod and looked upon a strange new world with my own eyes for the first time! It was a spectacular sight to say the least! This picture is not mine, I don’t have the money for astrophotographpy yet. The picture comes from http://www.tomsastroblog.com, but it is the exact same view that I saw through my binos on Christmas night 2011.