SOLAR SYSTEM MYSTERIES
Well, since we did medicine last week I thought we’d move to a subject that’s near and dear to my heart: space research. One of the things I love about my field is that it literally changes every day. What we believe today may definitely NOT be what we believe next week. And one of the biggest fields that’s changing every day is planetary science. That’s because we still have several intrepid robot explorers that are giving us daily reports about the conditions on Mars and Saturn.
The robot Cassini is in orbit around Saturn and we’ve learned more about Saturn and its many moons in the last four years than we learned in the previous 400. We’ve found new moons, seen a half-black, half-white moon (Iapetus) up close and learned that it has a 12-mile high mountain ridge around its equator. But one of the major objectives of the Cassini spacecraft was to explore Titan, the second largest moon in the solar system (after Jupiter’s Ganymede) and the only moon to have a substantial atmosphere.
NOT LIKE EARTH!
Cassini landed a probe on the surface of Titan. The surface had always been a mystery until Cassini because the atmosphere is opaque and we can’t see the surface from Earth.
The probe took many pictures in its spiral down to the surface and saw a landscape that was surprisingly Earth-like. There were mountains, cliffs and what appeared to be rivers flowing to large flat areas that looked suspiciously like large lakes or seas. But even though the surface looks like Earth, we knew it couldn’t be, because the average temperature on Titan is -290 degrees!
Interestingly enough, at those temperatures, water ice, as we know it, doesn’t exist. The only reason we have life here on Earth is that, unlike virtually any other compound, our kind of water ice floats on liquid water. If that weren’t true, the oceans would have frozen solid from the bottom up and we wouldn’t be here.
But at -290 degrees frozen water isn’t ice as we know it. Ice at the temperatures on Titan is water rocks; just like the familiar rocks here on Earth, but made of water. These water rocks would NOT float on liquid water (if there were any on Titan) they would sink like, well, a rock.
We are still studying the surface of Titan with radar and we’re discovering that the surface changes. Although scientists are still debating this, it appears there are volcanoes on Titan. They’re called cryovolcanos, which basically means ‘volcanoes’ much colder than you ever dreamed possible. And if the rocks that make them are made of water what are these volcanoes erupting? That’s right! Molten water!! Lava that is, in fact, water. They are probably also erupting liquid methane and ammonia. Certainly NOT Earth-like at all.
Is there life on Titan? We still don’t know, but we need to give up on the idea that life must be as we know it. The aliens will NOT be humans wearing monster costumes or sporting strange hairstyles.
A moon that erupts molten water. Strange indeed!
And now we’ll take a little trip from Saturn to Jupiter to have a look at the second biggest storm in the solar system and find out why it’s blushing.
SEEING SPOTS
A recent study has given new insights into why Oval BA, a giant anticyclone on Jupiter also known as Little Red, suddenly turned from white to red in a period of just a few months.
We all know about Jupiter’s Great Red Spot, a huge spinning storm that can be three times larger than Earth and has been on Jupiter’s surface for over 300 years.
A couple of years ago, I reported that a huge white spot had formed on Jupiter from a chain of white spot collisions that started way back in 1998. The large white spot that resulted was called Oval BA. Amateur astronomers reported a couple of years ago that Oval BA was beginning to turn red, but it wasn’t until April of last year that professional astronomers were able to image the impressive alteration of the second largest storm in the Solar System after the Great Red Spot (GRS).
The scientists that studied Little Red made an in-depth analysis of all the aspects regarding its history and evolution. The reddest color was concentrated in a ring around the spot’s center. But when the researchers calibrated images taken with the Hubble Space Telescope, they found out that Little Red didn’t actually change in red or infrared wavelengths. Instead, it became darker in blue and ultraviolet wavelengths, which made it look redder.
And the researchers didn’t limit themselves to data from Hubble. They also used images taken by the Cassini spacecraft on its way to Saturn as well as pictures taken by the New Horizons mission and computer models. They searched for possible causes for the color change, including alterations to dynamic, photochemical and diffusion processes.
Their conclusions? The most likely cause appears to be an upward and inward diffusion of either a colored compound or a coating vapor that may interact later with high energy solar photons at the upper levels of Little Red.
When they compared Little Red to The Great Red Spot, they found that the GRS is still redder than Little Red, most likely because it’s higher in Jupiter’s atmosphere, thicker and contains a higher concentration of the mysterious unknown chemical agents that give Jupiter its brownish-red color.
The scientists were able to rule out that the reddening was caused by any dynamic processes. They found no change to the strength of the “hurricane” and, although some changes in the circulation around the spot had taken place, the maximum wind speeds (which may range up to 250 mph or more!) were consistent with measurements previous to 2000 of Little Red or its white predecessors.
Their models also showed that the color change wasn’t caused by interactions of Little Red with the GRS, even though they were relatively close at the time. The flow around both vortices is so strong that it keeps the storms separate. They also ruled out the height of Little Red since it didn’t change; but there were large changes in the temperature gradient of the storm.
Bottom line? We STILL don’t know what causes the color, but we’ve ruled out several things that don’t. And that’s how science progress, you know. Ruling out one thing at a time that doesn’t fit what we actually observe. A slow process sometimes, but it works.
NOT ALWAYS ON THE LEVEL
One of the abiding ‘facts’ about our solar system is that virtually everything spins around the Sun on the same ‘table’. That ‘table’ is called the plane of the ecliptic and one of the things that made Pluto so unplanet-like is that its orbit is significantly inclined to the ecliptic plane. It doesn’t roll around on the same table as the planets.
Virtually the only things that humans routinely observe that don’t follow the ecliptic are the comets and an international team of scientists has found an unusual object whose backward and tilted orbit around the Sun may clarify the origins of certain comets.
In the first discovery of its kind, researchers from Canada, France and the United States have discovered an object that orbits around the Sun backwards, and tilted at an angle of 104 degrees – almost perpendicular to the orbits of the planets. This goes far toward proving that the comets exist in a large spherical cloud far beyond Neptune called the Oort Cloud.
The object is called 2008 KV42 and is made of icy rock. It’s also called a "trans-Neptunian" object since its orbital path is larger than that of Neptune. The object is roughly 30 miles across and about 3.5 billion miles from Earth.
We don’t normally look up or down in our solar system examination but the international research team has been carrying out a targeted search for objects with highly tilted orbits. Their discovery was made using the Canada-France-Hawaii Telescope in Hawaii, with fol
low-up observations provided by the MMT telescope in Arizona, the Cerro Tololo Inter-American Observatory (CTIO) four-metre telescope in Chile, and the Gemini South telescope, also in Chile.
The researchers had to use telescopes in both the northern and the southern hemispheres because 2008 KV42 would have been lost to view without the rapid tracking from the large telescopes in both hemispheres.
The discovery team is currently performing follow-up observations of 2008 KV42 to pin down its orbit with greater precision. They will then begin unraveling the archaeological information trapped in the orbit of this highly exceptional member of the trans-Neptunian population.
A near edge-on view of the solar ecliptic plane viewed from about 10 billion miles. This figure shows the orbits of Neptune (diameter 3 billion miles), Pluto, 2008 KV42 and 4 other ‘classical’ KBOs. Demonstrates the inclined nature of 2008 KV42’s orbit, when compared to other objects in the outer solar system. (Credit: Canada-France Ecliptic Plane Survey)
Volcanoes that erupt molten water, big red spots and strange visitors on a different plane. The solar system is full of wonder.
Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about space and many other topics. Enjoy!
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