Category Archives: cassini mission

astronomy news, cassini, cassini mission, evolution of galaxies, galaxies, globular clusters, omega centauri

Cassini Catches a Cluster

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Omega Centauri as Ring Backdrop

Well, this is kind of cool. The Cassini Mission out at Saturn happened to be studying the planet’s F ring and during the course of the observations caught view of the globular cluster Omega Centauri as it passed through the camera’s field of view.

The movie above is actually 13 images taken three minutes apart and then surgically joined together by the Cassini team to make the animation.  It clearly shows the cluster moving through the background.

Omega Centauri is really a spectacular naked-eye sight. It’s visible from throughout the southern hemisphere and lucky folks in more southerly parts of the northern hemisphere closer to the equator have a good vantage point for it, too. It has several millions stars packed into an area less than 90 light-years across.

The cluster lies about 15,800 light-years away from us, and is the largest of the globular clusters that are associated with the Milky Way Galaxy.  Omega Centauri may have played an interesting role in the evolution of our galaxy. Some astronomers suspect that it could have been part of a dwarf galaxy that was consumed by the Milky Way billions of years ago.  If this is true, then the cluster is what’s left of that galaxy’s core.  It’s an intriguing idea and one that astronomers are still researching.

On an unrelated note, if you’re a fan of the Carnival of Space, check out this week’s Carnival, written by Emily Lakdawalla.  Great stuff in there, including one of my own entries.

cassini mission, saturn, Titan

One Shimmery Lake

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Titan Has a Liquid Lake: is this News?  Yeah!!

A flash of sunlight glints off a lake on Titan, one of the moons of Saturn. Courtesy NASA and the Cassini Equinox Mission.
A flash of sunlight glints off a lake on Titan, one of the moons of Saturn. Courtesy NASA and the Cassini Equinox Mission.

I know this hit the news a few days ago, but it’s such an historical image that I wanted to show it here.

If you’ve been buried hip-deep in holiday preparations and celebrations, you might not have known that the Cassini Equinox Mission returned an image of Titan that shows a lake of liquid something on the surface of the cloud-shrouded moon of Saturn.  That lake is called Kraken Mare.

That little flash of light you see is a specular reflection off the surface of the liquid. Specular reflections are commonly seen on Earth when the sunlight flashes off bodies of water here. But, this is not likely to be water on Titan. Kraken is a hydrocarbon lake (hydrocarbons are things like methane and ethane). It stretches across about 400,000 square kilometers (150,000 square miles) across the northern surface.

Now, the cool thing about this image (along with the flash) is that we can actually even detect that glint. Most of the time Titan is covered in clouds.  Optically it makes it very difficult to see anything on the surface, but wavelengths of infrared light get through.  As Saturn and Titan approach their spring equinox, the viewing angle is just right, and scientists using an infrared-sensitive instrument onboard the Cassini spacecraft were able to detect the glint in infrared wavelengths.  This is pretty exciting news.  It’s cool because it’s there, first of all, and second because we’ve been able to see it with special instruments.  Third, the existence of that lake will help planetary scientists understand more about the interactions between the surface and the atmosphere of Titan and the conditions that help make the existence of that lake possible. Stay tuned!