Pac-Man On Mimas

Saturn’s icy moon, Mimas, has long been remarked for its large Herschel Crater giving it the appearance of the Death Star, the fictional space station of Star Wars fame.

Mimas

Death-Star-esque Mimas, imaged by Cassini — Click for high-resolution view

Perhaps Mimas inspired George Lucas when creating the Death Star? Nope; Voyager was the first to give us close-up views of Mimas, a few years after ‘A New Hope’ was in theatres.

But earlier this year, Mimas revealed another uncanny secret resemblance to something out of recent pop-culture history: Pac-Man!

Mimas Temperature Map

Mimas Temperature Map – Click for a Pac-tastic Larger Version

So what we’re seeing here is a map of temperature differences placed over a visual-light image of Mimas. If you think it’s curious that the highest temperatures seem to vary in such a way, you’re not alone:

“Even though we can’t explain the observed pattern of surface temperatures on Mimas, the giant Herschel crater is a leading suspect[.]” “The energy of impact that created it several billion years ago has been estimated to be one-seventh of Mimas’s own gravitational energy. Anything much larger would likely have torn the moon apart. We really would like to see if there is also an anomalous temperature pattern on the other side of Herschel, which has not been observed so closely.” – Dr. Mike Flasar, composite infrared spectrometer principal investigator from NASA Goddard Space Flight Center.

The following image gives an idea of how what’s actually occurring on Mimas compared to what would previously be expected:

Comparison of different images of Mimas.

Comparison between expected temperature-map, actual temperature-map, visual light, and actual temperature-map layered on visual light images. – Click for full version.

A leading theory is that different textures of surface materials (mostly water ice with small amounts of rock) are holding on to heat from the Sun differently, but what is still not understood is why such sharp boundaries exist between these textures — giving the Pac-Man shape. It’s possible that the impact that caused the Herschel Crater distributed the more heat-absorbent materials in that pattern, but Mimas is constantly bombarded by impacts (as can be clearly seen when viewing the high resolution image of Mimas above), which you’d expect to destroy long ago any non-uniform surface make-up.

So for now, no definite answer is available. Luckily, we have the amazing Cassini orbiter up there, collecting more data for the scientists to work with.

Astronomy Art – The Cosmos Gallery

I came across a website showcasing some very beautiful art, this morning. Fine art + Astronomy is a magical equation. See for yourself:

Jupiter's Red Spot

Red Spot of Jupiter

Purchase some of this original and amazing art and/or help contribute to the artist’s next project.

Cosmic Paparazzi – Saturn and Tethys

Saturn and moon Tethys

Saturn and moon Tethys


(Click image for full resolution)

This view of Saturn, its rings and the moon Tethys represents “Target 1” in the fall 2009 edition of the Cassini Scientist for a Day contest. (See http://saturn.jpl.nasa.gov/education/scientistforaday8thedition/.) The contest is designed to give students a taste of life as a scientist by challenging them to write an essay describing the value of one target choice among three for Cassini to image.

A bonus feature in the image is the presence of bright spokes on and just above the ansa, or curved edge of the darkened ringplane. The spokes are made visible here by sunlight scattering through the dust-sized icy particles and toward Cassini’s cameras.

Images taken using red, blue and green spectral filters were combined to create this color view. The images were acquired with the Cassini wide-angle camera on Oct. 11, 2009 at a distance of 1.7 million kilometers (1 million miles) from Saturn. – NASA

Geminids Meteor Shower – Live Webcam

Cloudy skies, but still want to see the Geminids?

NASA has created a live webcam feed from their all-sky meteor camera at the Marshall Space Flight Center. A radio-static “soundtrack” is being played along with the video.

When a meteor burns up in the atmosphere, it also produces a trail of ionized particles that reflect radio waves. If the meteor is located in the right spot in Huntsville’s sky, the signal from the station transmitter is reflected to the radio receiver, and you will hear a “ping” above the static noise. – NASA

If you have clear skies, make it a late night and watch what should be a brilliant meteor shower. If the handful of fireballs I’ve seen over the past few nights are any indication, we should have a nice show as the Geminids peak this evening and into tomorrow morning. The best views will certainly be after the Moon sets, especially between 1am and 3am local time; however, if you cannot stay up that late look towards the East before you go to bed and you should see a handful.

Ascent – Commemorating The Shuttle Program

This video is making its rounds on the internet. It serves as a beautiful tribute to NASA’s shuttle program. The video is 45-minutes long, but you don’t have to watch it in one sitting; in fact, you can skip around a bit and just enjoy the amazing high-definition, slow-motion, videos of the shuttle systems.

It’s going to be very difficult to say goodbye to the shuttle program, early next year.

Akatsuki Fails Venus Orbit Attempt – Oh Well, We'll Try Again… In Six Years

Akatsuki - Planet-C

Planet-C Akatsuki | Image credit: Akihiro Ikeshita and JAXA

JAXA’s (Japan Aerospace Exploration Agency) third planetary explorer, Planet C (Akatsuki), failed to enter Venus’ orbit following a journey that lifted off in May of this year.

According to JAXA:

The Institute of Space and Astronautical Science of the Japan Aerospace Exploration Agency (ISAS/JAXA) performed Venus orbit insertion maneuver (VOI-1) for the Venus Climate Orbiter “AKATSUKI” at 8:49 a.m. on December 7 (Japan Standard Time,) but, unfortunately, we have found that the orbiter was not injected into the planned orbit as a result of orbit estimation.

JAXA has set up an investigation team to try and understand why the orbit insertion failed. While control has been reestablished, “the spacecraft is functioning but has put itself in a standby mode with its solar panels facing towards the Sun. It is also spinning slowly — about every 10 minutes — and radio contact is possible only for 40 seconds at a time.

If control is able to be completely regained, there will be an opportunity to re-try entering Venusian orbit in six years — Akatsuki doesn’t have the fuel to hit the brakes and go back for another go at it.

This will mark the second JAXA planetary explorer that failed to complete its mission. Planet-B — dubbed “Nozomi” — failed to enter Mars orbit in 2003. That mission was abandoned, but the spacecraft is currently still active.

While the challenges of space travel have proven frustrating for JAXA, the agency cannot be said to not have its successes. Planet-A (“Suisei”) came within 151,000km of Halley’s Comet in 1986, as part of an international armada of probes sent to the renowned iceball during its last approach to our neck of the solar system.

Suisei

Planet-A | Suisei

IKAROS

IKAROS

In addition to that, they have another very nifty, and successful, vehicle out there named IKAROS (“Interplanetary Kite-craft Accelerated by Radiation Of the Sun”). IKAROS is an experiment designed to demonstrate solar-sail technology as a means of traveling interplanetary space. IKAROS is an exciting little machine and I intend to devote an entire post to it in the near future.

Space exploration has come a long way in a very short amount of time, but we continually have these pesky failures to continually remind us that it is also very challenging. As frustrating as these complications may be, we can still appreciate the lessons learned and apply them to the success of future endeavors.

Cosmic Paparazzi – Pismis 24

Pismis 24
(Click to biggify)

The small open star cluster Pismis 24 lies in the core of the NGC 6357 nebula in Scorpius, about 8,000 light-years away from Earth. The brightest object in the center of this image is designated Pismis 24-1 and was once thought to weigh as much as 200 to 300 solar masses. This would not only have made it by far the most massive known star in the galaxy, but would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars.

However, Hubble Space Telescope high-resolution images of the star show that it is really two stars orbiting one another that are each estimated to be 100 solar masses.

In addition, spectroscopic observations with ground-based telescopes further reveal that one of the stars is actually a tight binary that is too compact to be resolved even by Hubble. This divides the estimated mass for Pismis 24-1 among the three stars. Although the stars are still among the heaviest known, the mass limit has not been broken due to the multiplicity of the system.

The images of NGC 6357 were taken with Hubble’s Wide Field and Planetary Camera 2 in April 2002.

ImageCredit: NASA, ESA, and J. Maíz Apellániz (Instituto de Astrofísica de Andalucía, Spain)

(Source)

To Boldly Go

Mars, from Hubble 2005The Journal of Cosmology recently published a proposal (Journal of Cosmology, 2010, Vol 12, 3619-3626.) for the exploration settlement of Mars. This proposal, however, is a little different than most consider when thinking of interplanetary travel.

These missions would be one-way.

Myriad space-exploration resources and money go into making the return-trip possible, and many argue that that cost is too great, financially and politically. The authors of the article, Drs. Dirk Schulze-Makuch and Paul Davies, agree. They say to scrap the return mission.

What they propose is that we (the humans of Earth) send two space crafts to Mars, each with two people on board. Those initial four people would create the infrastructure and conduct science and research for future one-way missions. Prior to this, some robotic exploration would be advised, to deploy power generators, deliver a couple years supply of food, supply agricultural equipment, seek out areas on Mars suitable to shelter human habitation (lava tubes are mentioned), and to research any Martian biota that may exist (primarily to understand what effects it could have on human health, as well as what impact human interference could cause to Martian life).

Future missions would follow, bringing additional tools, supplies, and resources, and additional human inhabitants. They reason that within several decades after the first pioneers land, a possible population of about 150 Mars emigrants would exist. This could constitute a viable gene pool for a permanent reproduction plan on Mars.

Why? I can think of thousands of reasons.

For starters, because the project is technically feasible to begin today. With current technologies and capabilities, a successful mission of this sort is quite feasible. We did it on a nearer scale with the Apollo missions to the Moon, and that was more than 40 years ago. Sure, there are greater challenges related to the distance (about 6 months with current chemical rockets to Mars vs. 3 days it took the Apollo missions to get to the Moon) and environment of Mars compared to the Moon; but again, you can subtract the return portion of the mission from the equation.

Additionally, our species will not survive on Earth forever (super volcanoes, intolerable global warming, asteroid impacts, pandemics, etc.). Mars could function as a lifeboat for human species, and the advances we make in the process could accelerate our ability to become an interstellar race. If the human race is to survive, we simply must travel. [We cannot forget, that within a small handful of billions of years, the Earth will be cremated as the sun converts into a red giant; expanding to a point that the Sun’s equator will possibly exist at a point further than the current orbit of the Earth.]

Aside from utilitarian reasons, exploring and populating new frontiers is part of what makes us human. It’s what we do. We’ve accomplished amazing things in the short history of our species. We’ve conquered the lands, seas, and air. Humans have descended to the deepest depths of our oceans (Jacques Piccard and Lieutenant Don Walsh descended to Challenger Deep in the Marianas Trench, aboard the Bathyscaphe Trieste, in 1960) and climbed the Earth’s highest peaks. We’ve learned to fly and have had an uninterrupted human presence in Earth orbit for more than a decade. We’ve gone as far as putting our species on our nearest natural neighbor, the Moon, on multiple (the last being 38 years ago; Apollo 17) occasions. And while we have explored, and are currently exploring, our solar system, it has always been by proxy. Our probes (Voyager 1 & 2 are still returning data after 33 years, as well as other probes) and rovers (Opportunity is humming along on the Martian surface, and I’m hoping Spirit will eventually wake back up.)

Mars is the next step in the walk of human destiny. If we can’t muster the political will to take that step, then our journey is over and we’ll live out the rest of our existence — a flash in time — on this currently habitable rock. The question we must ask ourselves is whether or not this is good enough.

I’ve spent hours staring at Mars, whether with my eyes, or through the eyepiece of my cheap telescope.

If given the opportunity to participate in one of these missions, I’d sign up; if for nothing else, to have the same view of Earth, behind the eyepiece of a cheap telescope on Mars.

The Deathstar…. Err… Mimas

Cassini never ceases to amaze me.

Saturn has moons. Lots of moons (at least 62). And I find each one of those moons to be equally interesting.

Recently, the orbiter, Cassini, snapped the following photo of one of Saturn’s moons, Mimas.

Mimas
(Click image to BIGGIFY)
Mimas is the twentieth largest moon in our solar system, yet is the smallest astronomical body that is believed to be round in shape due to its self-gravitation. Mimas has an interesting feature in a huge crater named Herschel. Compared to Mimas, this crater is huge. It is 80 miles (130km) wide, which is about a third of the total size of the moon itself (wider than Canada). As Phil Plait points out, the impact that created this crater was just about as big as it could have been without obliterating Mimas.

The results are beautiful. Some see the crater resembling a big eye. To many, including myself, it looks like the Deathstar:
Deathstar
(That’s no moon. It’s a space station. – Obi-Wan Kenobi)

For a mission that began in 1997, Cassini (Cassini-Huygens originally, until the Huygens probe was sent to land on the surface of Titan) just keeps on keepin’ on. It has had its missions and extended multiple times, and will most likely keep snapping these shots until it makes a flaming plunge into Saturn’s atmosphere in 2017. NASA, and its counterparts from around the globe, have done a fantastic job of completing their main missions, and then coming up with ways to continue using them for additional missions. We’re learning new and amazing things on a regular basis, and I think that’s just grand.