Weird Hills on the Surface of Titan

Titan is one of the one of the most exciting places in our solar system. This moon of Saturn has liquid methane playing the role of water on its surface, and water ice playing the role of solid rock. We are just beginning to understand the dynamics at work on this moon, in part because it is shrouded in a thick methane atmosphere. This image was taken on December 28th, 2009 and is giving sicentists new puzzle to solve.

The lines you see in the lower left of the image are rifts similar to features called corona on Venus. On Venus, we think they are caused by heat within the planet that puts stress on the rock. Straight features like this could also be created by surface activity like wind or rainfall.

The star-shaped feature to the right also points to some sort of activity happening in this area. “This star-shaped pattern of the hills indicates something significant happening in the middle of the star,” said Steve Wall of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., a Cassini scientist on the radar team. “It might be caused by tectonic forces, such as the forces that pull the crust of a planet apart, or rainfall that leads to erosion, or an ice intrusion like a dike.”

Scientists don't have any answers yet, but either answer would be exciting. If this was caused by rain, it gives us a better understanding of how liquid methane shapes the surface of Titan. If on the other hand it is caused by some sort of internal heat, it raises all new questions on what the inside of Titan is like. We will just have to wait as Cassini continues to unveil this exciting world.

Image Credit: NASA/JPL

A Glimpse of Lakes on Titan

Imagine a world so cold that temperatures like -270 Fahrenheit are not uncommon.Water acts more like rock, and a thick orange atmosphere looms overhead. Instead of water carving up the landscape, you have methane. This is Saturn's moon Titan.

This image is of sunlight bouncing of the lake Kraken Mare taken by the Cassini spacecraft. This lake of liquid methane is larger than the Caspian Sea here on Earth. Titan is a fascinating world because of how it compares to the Earth. “These results remind us how unique Titan is in the solar system,” said Ralf Jaumann, a visual and infrared mapping spectrometer team member on Cassini. “But they also show us that liquid has a universal power to shape geological surfaces in the same way, no matter what the liquid is.”

There has been building evidence for lakes on Titan even before Cassini arrived at Titan. This picture is a elegant piece of evidence confirming those weird lakes. “This one image communicates so much about Titan -- thick atmosphere, surface lakes and an otherworldliness,” said Bob Pappalardo, Cassini project scientist, based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “It’s an unsettling combination of strangeness yet similarity to Earth. This picture is one of Cassini’s iconic images.”

Titan is one of the most exciting places in the solar system to explore. I think this just gives a taste of what awaits us.

For more information: Cassini Homepage
Image Credit: NASA/JPL/University of Arizona/DLR

A New Face to Saturn's Rings

Over the last few months, we have been treated to a series of images of long shadows cast across Saturn's rings.  This unique viewing opportunity happens about every 15 years as Saturn approaches equinox.  The low angle of the Sun's rays across the rings has been great for science and, of course, produced some amazing photos.  August 11th was Saturn's equinox, so now the opposite side of the rings is being lit up by the sun.

In this bottom image you can see Titan and the shadow that it's casting on the planet.  Both of these are raw images from Cassini so they're a little rough but still give a sense for Saturn's grandeur.  Click on the images to a larger version.

In my opinion, Cassini has produced more eye candy than any other spacecraft we have put up there.  I hope that Cassini will continue to function for many more years before it is crashed into Saturn.  Imagine what we would see and learn if we sent a Cassini-like mission to each of the outer planets.  I hope the folks at NASA recognize the public interest these images have produced and will try for more missions that will be able to capture the majesty that space has to offer.

All images are credit NASA/JPL/Space Science Institute

This is just Amazing!

For me there are two things that I just love in astronomy: pretty pictures and violent collisions. When the two come together, you get amazing images like this.

This incredible image is of something careening through Saturn's rings. Whatever this object is, as it's sailing though the rings, it's dragging a trail of debris behind it. The long shadow is being cast because Saturn's rings are almost edge on towards the sun. The exact process that created this dazzling effect still seems to be a mystery. For more on this check out Phil Plait's blog. Whatever it is it's awesome. This is why I love science.

Enceladus's Ocean Debate

Last month I wrote about how scientists were in a heated debate on whether or not Saturn's moon Enceladus has a sub-surface ocean. This is cutting-edge science. We have both sides trying to get more evidence and figure out what's going on with this weird moon. Yesterday, NASA released a new piece of evidence that may tip the scales.

A team from the Southwest Research Institute in Texas, used the spectrometer on Cassini to find ammonia in the plumes that are shooting out of Enceladus's surface. The interesting thing about ammonia is that it is an antifreeze. According to the NASA report ammonia can allow the water to remain a liquid at temperatures as low as -143 degrees Fahrenheit. Hunter Waite, the Cassini Ion and Neutral Mass Spectrometer Lead Scientist from the Southwest Research Institute in San Antonio said "Given that temperatures in excess of 180 Kelvin (-136 degrees Fahrenheit) have been measured near the fractures on Enceladus where the jets emanate, we think we have an excellent argument for a liquid water interior."

This is a really interesting result and has powerful implications. I predict, however, that this will not end the debate. We really need some piece of definitive evidence. I hope that there is a liquid ocean because that opens up the question of whether or not there is life on Enceladus. The moons of the outer planets are exciting places that I am sure have many more surprises in store. I can't wait to see what they are.

Source- NASA

Enceladus has an Ocean?

In 2005, the amazing Cassini spacecraft saw plumes of water shooting out from the south pole of Saturn's moon Enceladus. Ever since the question has been is there a ocean under the sheets of ice that cover the surface of this weird moon. If there is an ocean, it raises the question of whether or not these is also life. Needless to say, this is a question everyone wants to know the answer to. If an ocean is there, scientists expect sodium to be dissolved in the water shooting out of these jets. So the search for sodium began.

In the last issue of Nature, two studies came out looking for this elusive piece of evidence. Both groups used spectroscopy. This is where you break down light into its different colors. When you do this each element and molecule has a distinctive fingerprint. Using this teqnuqie one group thinks they found sodium in the water, and another says it's not there.

The group from the Cassini spacecraft team says that they have found sodium. The other group was using two of the best ground based telescopes in the world. They say that sodium is absent from the water. So what do we do? Rarely in science do you get opposite results published at the same time. Both sides have strong evidence, and are both in one of the most prestigious science journals. Really, the only thing we can do is wait for more evidence.

Cutting edge science is thrilling. We are always learning new things, and those things always manage to surprise us. I just can't wait to see what happens.

The suspense is killing me!

Sources - NASA

Universe Today

Keck Observatory

Scientific Unknowns: Saturn's Hexagon

When most people think of science, they think of a body of knowledge. Science has discovered a lot of really cool things, but what we know is just the beginning. There are lots of really cool things that we don't understand as well. Unfortunately, I think that these get overlooked too often. For that reason, I am starting weekly series of things that are on the leading edge of science. Amazing phenomena that we don't yet understand. It is the nature of science to grow. Every question we answer makes us ask many more. Someday these mysteries will be solved, but there will be many more to take their place.

When we look at planets we expect to see lots of shapes. Most planets are basically spheres. We see conical volcanoes, circular craters, and stripes of different colored clouds. One shape we don't expect to see are hexagons. Luckily, the universe is far weirder then our expectations. The clouds around Saturn's north pole have made a hexagon!

In my opinion Cassini is one of the most successful spacecraft ever. Of all the great discoveries that it has made, though, this is one of the weirdest. This picture was taken in infrared light (5 microns). This means that what you're seeing is a type of light that represents heat. It also means that you are looking beneath the top layers of clouds. The clouds you see are between 45 and 60 miles below the top layer.

The south pole of Saturn is also weird. Instead of hexagon, though, it has a cyclone system. I don't want to go too deep into this feature, but it is weird to have such a stark difference between the poles. Bob Brown, from the University of Arizona, says, "At the south pole we have what appears to be a hurricane with a giant eye, and at the north pole of Saturn we have this geometric feature, which is completely different."

Source- NASA