Cassini-Huygens Update

Up close and Personal with Titan. This is a false colour picture. They are reconsidering the possibility of life on Titan again.

Recent findings from NASA's Cassini spacecraft and new discoveries about organisms here on Earth that thrive in extreme conditions are causing scientists to rethink the possibility that there may be life on Saturn's cloudy moon Titan.

Analyzing data from Cassini's recent Titan flybys, scientists at the Southwestern Research Institute (SwRI) in Texas and Washington State University announced last week that several of the key elements crucial for life on Earth are also present on Titan, including liquid reservoirs, organic molecules and ample energy sources.

Do tell, y'know?

Hey, It's A Brave New World



I've been busy lately as the low rate of posting indicates. It never rains, it pours. So too with work, which is good for a change. The fuzzy pic you see is the landscape of Titan.

When the Huygens space probe landed on Titan, the area around the lander is a soft patch of material similar to lightly packed snow. But to get to that soft patch, Huygens had to descend through a treacherous atmosphere with winds ranging up to 270 mph. Temperatures also dropped as low as -333 degrees Fahrenheit, and lightning was about.

Nearly a year after the probe landed on Saturn's largest moon, scientists are still poring over loads of data. Today, researchers released their newest findings in a series of seven reports. The findings provide a better picture of some of the most basic characteristics of Titan, a smog-shrouded world that had eluded close scrutiny until Huygens and the Cassini mothership teamed up for a series of observations.

Scientists had long suspected that Titan's atmosphere was moving around the moon faster than the moon was rotating – a physical characteristic known as superrotation and previously observed on Venus. Now, data from the probe's DISR instrument and the Doppler Wind Experiment have confirmed that Titan's methane filled clouds do indeed superrotate.

While the uppermost clouds – about 75 miles above the surface – spin around the moon at about 270 miles per hour, wind speeds gradually decline as the near the surface. Here generally weak winds, gusting no more than a few feet per second, were observed in the lowest 3 miles of the probe's descent.

The probe passed through one other region of near zero wind speeds, from altitudes 62 to 37 miles. Scientists cannot explain this yet.

During its descent, Huygens provided the first in situ look at what chemicals exist in Titan's atmosphere. The atmosphere is mainly nitrogen and methane, but scientists didn't know how these chemicals originated – did they arrive in their present form or were they originally part of other molecules and were chemically altered to the states seen today.

The gas argon 36 was detected by the Gas Chromatograph Mass Spectrometer in very low abundance, and scientists say this indicates that nitrogen was originally present as part of ammonia. Also, the early atmosphere of the moon was at least five times denser with nitrogen than it is now, suggesting that some of the gas has been lost into space.

Ratios of carbon isotopes also indicate that the atmosphere is also leaking methane, and that there must be some period method for replenishment, although none was observed. Some researchers predicted there would be a large methane surface or subsurface reservoir that replenished the atmosphere, although that too was not seen. Also missing from the observations was the signs of methane rain, which scientists believed showered the moon's surface.

Which is all very nice. The next pic is from this article.

This perspective view shows dark plains on the surface of Saturn's moon Titan about 3 miles (5 kilometers) from the Huygens probe landing site. In this area many discrete bright feature are scattered across the dark plains.

This provides stereo coverage with a resolution of about 45 feet per pixel (about 14 meters) and a convergence angle of about 6 degrees. The perspective image is color-coded in altitude with blue lowest and red highest. The ridges in the center of the view are about 150 feet-high (roughly 50 meters); the area covered is about 1.6 miles by 1.6 miles (2.5 by 2.5 kilometers). The topographic features toward the bottom right part of the view are suggestive of flow and erosion by fluids on the surface.

There's a full resolution version here.
The next picture is a portrait of a near full alignment of Saturn's moons. Of course as we know Iapetus is waywardly off the plane. The article is here.

Seen here are Titan (5,150 kilometers, or 3,200 miles across) and Dione (1,126 kilometers, or 700 miles across) at bottom; Prometheus (102 kilometers, or 63 miles across) hugs the rings at center; Telesto (24 kilometers, or 15 miles across) is a mere speck in the darkness above center.

The image was taken in visible light with the Cassini narrow-angle camera on Oct. 17, 2005 at a distance of approximately 3.4 million kilometers (2.1 million miles) from Dione and 2.5 million kilometers (1.6 miles) from Titan. The image scale is 16 kilometers (10 miles) per pixel on Dione and 21 kilometers (13 miles) per pixel on Titan.

Yeah.

Shuttle Might Go Ramp-less In Next Flight



I don't know how this would work, mostly because I'm no expert, but this article suggests the next shuttle flight might fly without the foam ramp in its next trip.
The picture above is an image taken after separation with the shuttle and shows where the foam fell off.

Into A Bright Sun




This article covers the SOHO project, which brought us images like the one above.

This brings us to SOHO, also a joint American-European project, and another epic solar voyage still underway. Launched Dec 2, 1995, its array of instruments were designed to study the solar wind, as well as the Sun's outer layers and interior structure.

In order to do this, it was placed in an orbit 1.5 million kilometers from Earth, at a point known as the L1 Lagrangian point, where the combined gravity of Earth and Sun keep it in an orbit locked to the Earth-Sun line. Though still far from the Sun, this location, about four times the distance of the Moon in the direction of the Sun, is ideal for long-term uninterrupted observations with the Earth out of the way.

SOHO's scientific findings have been phenomenal. It has imaged the structure of sunspots below the surface, measured the acceleration of the wind from the Sun (streams of protons and electrons traveling at a million miles per hour!), discovered coronal waves and solar tornadoes, and found more than 1000 comets.

Moreover, it has revolutionized our ability to forecast space weather, and provided data on the variability of the Sun's energy, both of which affect us directly on Earth. Some 140 Ph.D. theses have been written using SOHO data, and almost 300 meetings held to discuss its findings.

And what images SOHO has returned during its ten years! Both still images and movies showing the dynamic Sun's prominences, flares, spots, coronal mass ejections, and otherwise lively gyrations fill the SOHO website at http://sohowww.nascom.nasa.gov

As with most voyages, SOHO has remarkable stories to tell, mostly of what it has seen. But there are other stories: for example, of the day on June 24, 1998 when a ground controller accidentally turned the satellite to face away from Earth. The satellite was feared lost, but a month later the enormous 305-meter radio telescope at Arecibo, Puerto Rico found SOHO.

And I never knew about it.