Jurassic Park 4

Our best guess at what Deinonychus looked like.

Jurassic Park 4 is scheduled to hit theaters on June 13, 2014, so this might be a good time to have a little heart-to-heart discussion with Mr. Spielberg on a few technical details. It’s been 20 years now since Jurassic Park first came out in theaters and paleontologists have learned a great deal since then. 
   Even though the appearance and behavior of dinosaurs is largely speculation, there are a few things that could be updated. From preserved specimens showing quill knobs, we know that Velociraptor had feathers, probably colored black, white and rust brown. And based on their size, those dinosaurs should be called Deinonychus.
   Crichton’s central idea was that the amber which preserved the mosquito also preserved the dinosaur blood from contaminants and harm—a simple idea which made for a compelling story. But there are definitely issues with this. You can’t get dinosaur DNA from a dead mosquito trapped in amber. After sitting in a chunk of resin for millions of years there is going to be mixing of the mosquito’s DNA and the DNA of whatever it fed on and anything else trapped in the amber. Even if it could be done, there’s no way of knowing what kind of animal a mosquito had bitten. How many would Hammond have to go through before finding one that had actually bitten a dinosaur? Not to mention how would extinct plants get cloned since mosquitoes don’t eat plants.

A 70-million-year-old T. rex
fossil has yielded soft tissue.

   There’s a better way. One of the biggest developments in paleontological research in the last two decades has been the discovery of soft tissues preserved in fossil bone interiors. These bones come from the badlands, and are excavated using sterile field techniques and without protective polymers and glues to keep contaminants from entering the bone interiors. The fossils are then taken back to a lab where the mineral components are dissolved in baths. If the dinosaur bones were truly permineralized then the entire fossil would basically dissolve in solution. But that didn’t happen when the first lab tests of this kind were conducted back in the early 2000s. After the mineral components had dissolved away, there was spongy, squishy, soft stuff left over. Paleontologists had discovered bits of tissue, blood remnants and marrow from their samples. This was absolutely unheard of when Crichton wrote Jurassic Park. Even though it’s not yet possible to retrieve 70 million year old DNA, this method is much closer to reality than sucking out dinosaur blood from a fossilized mosquito. If you want a park with a triceratops in it, just head out to the Badlands, find some triceratops bones, and mine them for their soft tissues.
   The other big change for Jurassic Park would have to be the DNA gap-filling. No more frog DNA. They would need to use bird DNA, preferably a more primitive species like an emu or ostrich. There has been a lot of genetic work done on chickens lately, so chicken DNA might work as well because we know so much about it. In a movie, it would not be much of a stretch to say that we have control over the chicken genome, and thus could reduce it back to a stem state, where the combination of the dinosaur DNA with the trimmed chicken genome lets you build a dinosaur.
   Not only could you clone dinosaurs with the soft tissue story line, but marine dinosaurs, too. Giant ichthyosaurs, mosasaurs, plesiosaurs—there was plenty of scary stuff in the ancient seas. For the purpose of a movie, anything that’s fossilized could be fair game. There are plenty of big, scary extinct animals to choose from...

The Golden Tortoise Beetle

The Golden Tortoise Beetle (Charidotella sexpunctata)

The golden tortoise beetle is a common North American beetles that lives on and eats morning glory leaves. They can also be found on sweet potatoes which belong to the morning glory family. Both larvae and adults feed on foliage of which they make many small- to medium-sized irregular holes. Rarely are tortoise beetles numerous enough to be considered damaging to the host plants.
   In spring and summer, the beetle earns its name by turning the color of brilliant liquid gold. The color is produced by an optical illusion—the outer cuticle is transparent and reflects light through a layer of liquid over the next layer of cuticle. The beetles change color depending on the availability of the liquid layer which they control through microscopic valves under their shell. In the fall and winter, the beetles become less lustrous and are more orange and bronze often with black spots similar in appearance to ladybugs. If you try and add the beetle to an insect collection, it quickly turns dark brown as is dries, and looses its golden color. The beetle is most beautiful while alive.

   The larvae hatch out in late May and June and are just as interesting as the adults, but in a much different way. The young larvae are surrounded by many small protuberances giving them a spiny appearance. As the larvae molts, it keeps its old skin attached to a fork-like structure hinged to its rear end. The larvae will add its own feces to the old shell to create a type of shield which it can use for defense. When they are disturbed by another insect or predator, they flip the shield up in the direction of the disturbance. This "poo protector" is an unappetizing and effective deterrent against potential predators looking for a meal!

All Eyes on ISON

Comet C/2012 S1 (ISON) shares many of the same
characteristics as the Great Comet of 1680.

Be sure to keep tabs on comet C/2012 S1 (ISON), which is hurling toward a close approach with the sun this fall. Even though ISON is still a long way away, located just inside Jupiter’s orbit, it has already formed a tail of gas and dust stretching 90,000 km.
   This is thought to be the comet’s first pass into the inner solar system and promises to provide us with a spectacular show between November 2013 and January 2014 after it has its close encounter with the Sun.
   C/2012 S1 was discovered in September 2012 by two amateur astronomers using the International Scientific Optical Network in Russia, hence the nickname ISON has been adopted by the media.
   ISON has been recently observed by NASA’s Deep Impact spacecraft. Deep Impact, which was launched in January 2005, was originally used to study comet Tempel 1 by hitting the comet with a small metal probe then doing a close flyby to study the debris it kicked up. In 2010, Deep Impact flew past comet Hartley 2 and is now on its way to a January 2020 visit to a near-Earth asteroid that is large enough and close enough to us to be classified as a potentially hazardous object (PHO) by NASA.
   C/2012 S1 will be well placed for observers in the northern hemisphere during the last two weeks in December 2013. Some speculate that if it does not break up as it reaches perihelion it could become brighter than the moon at its peak, but many sungrazing comets do not survive the encounter. It has been calculated that as it nears the Sun it will reach a peak temperature or 2,700°C, hot enough to melt iron. 
   ISON’s orbital path is similar to that of the Great Comet of 1680, another sungrazer that is also known as Newton’s Comet because Isaac Newton used it to verify Kepler’s laws of planetary motion. Newton’s Comet was one of the brightest comets of the 17th century. It was noted for its extremely long tail and at its peak it was bright enough to be seen during the day. Time will tell if ISON will someday be known as the Great Comet of 2013.

The Oh-My-God Particle

One of the two Fly's Eye Cosmic Ray Detectors.

The Oh-My-God particle was an ultra-high-energy cosmic ray—most likely a proton—detected on October, 1991 in the skies over western Utah. Its observation by the University of Utah's Fly's Eye Cosmic Ray Detector was a shock to astrophysicists, who estimated its energy to be approximately 50 J. In other words, a subatomic particle with kinetic energy equal to that of a baseball traveling at about 90 kilometers per hour.
   The particle was traveling at almost the speed of light. Assuming it was a proton, its speed was only about 1.5 quadrillionth of a meter per second less than the speed of light. In other words, if it were in a race with a beam of light, the Oh-My-God particle would fall behind only one centimeter every 220,000 years.
   The energy of this particle is some 40 million times that of the highest energy protons that have been produced by the Large Hadron Collider. However, only a small part of this energy would be available for an interaction with another proton or neutron. Most of the energy would remain as kinetic energy. The effective energy available for such an interaction is still 50 times greater than the collision energy of the Large Hadron Collider.
   Applying special relativity to such a fast particle yields some incredible results. Time passes more slowly as velocity increases, and for anyone hypothetically travelling on the back of this particle time would nearly stop. For example, a trip to the Andromeda Galaxy, which is more than two million light years away, would have a perceived travel time of only three and a half minutes. Special relativity also tells us that there is a length contraction in the direction of motion. If the Earth were somehow able to match the speed of the Oh-My-God particle, it would pancake down to a thickness of less than four hundredths of a millimeter!
   The University of Utah experiment relied on two telescopes searching the sky for the characteristic flashes of ultraviolet light that are produced when a cosmic ray collides with a molecule in Earth’s atmosphere and creates a shower of secondary particles. The two telescopes were covered in photomultiplier tubes and looked like the compound eyes of a fly. By capturing almost all the light in the shower, they were able to make a good measurement of the particle’s energy.
   These ultra-high-energy cosmic rays are very rare. Since the first observation, only about fifteen similar events have been recorded to confirm the phenomenon. What cosmic process transforms an ordinary particle into an Oh-My-God particle? A supernova or supermassive black hole might explain it, but when astronomers followed the impact track back to its source they found nothing unusual in that direction.

The Water Bear

The tardigrade is also known as the water bear.

A polyextremophile is an organism that can survive many types of extreme environments. One of the most complex polyextremophiles is the tardigrade, which can live in just about every environment possible here on earth, plus some not on Earth (more on that later). Tardigrades are about a millimeter long when fully grown. They are short and plump with eight tubular legs, each with 4-8 bear-like claws. Given that they also move like a lumbering bear, tardigrades have earned the nickname water bear.
   Tardigrades typically live in marine, fresh water, or semiaquatic environments, but you can also find them in the mosses and lichens found in forested areas. As long as there is some water around, they can thrive. They feed on the fluids found in plant and animal cells. Their mouth is able to pierce the cell walls so that they can then suck out and ingest the inner parts of the cell. 
   Tardigrades can survive being completely desiccated for nearly 10 years as well as exposure to high levels of chemical toxins. They can survive extreme heat (150 °C) for a few minutes and extreme cold (-200 °C) for a few day. When exposed to extreme cold their body composition changes from 85% water to only 3% which keeps their body from being damaged by ice crystal formation. 

   The can survive extreme pressures far greater than that found at the Mariana trench. In 2007, tardigrades were sent into space on the Russian/EU satellite Foton-M3 for ten days. Even after being exposed to the vacuum of space for this long, most of the samples survived after being rehydrated back on Earth, some of which had also been fully exposed to the Sun’s radiation. Tardigrades were also sent into space on the final flight of Space Shuttle Endeavour where experiments showed that cosmic radiation and microgravity did not significantly affect their survival, confirming their usefulness in space research.
   You’re probably wondering just how these creatures could be so resilient. They rely on cryptobiosis—a state of suspended animation that they can enter in response to adverse environmental conditions where all metabolic processes stop. Their bodies dehydrate into a dense, mummified disc called a tun. They can remain in this state indefinitely until their environment becomes hospitable once again. When this happens, the tun plumps back up and the tardigrade return to its previous metabolic state.

Dangers of a Vacuum

The vacuum chamber that Jim LeBlanc was in
when his spacesuit lost all pressure.

Recently, a reader asked “What happens to the human body in a vacuum? For example, if an astronaut removed his space suit.”
   This reminds me of a scene from the movie 2001: A Space Odyssey. In the movie, HAL has figured out that Dave is planning to disconnect him when he returns to the ship, so he refuses to let Dave back in. Dave is forced to go in through the unpressurized emergency airlock, but there’s a problem: he doesn’t have his space helmet. 

  Terrifying, but Kubrick got the science right. Short-term exposure to the vacuum of space would not make your body explode or freeze solid as some movies have depicted. If you don’t try to hold your breath, exposure to space for about 15 seconds would cause no permanent injury. Holding your breath would be bad, though, because in a vacuum your lungs collect gas from your bloodstream and expands with the drop in pressure. Holding your breath would cause your lungs to overinflate and possibly rupture. This is similar to how scuba divers need to exhale when rising to the surface or risk damaging their lungs. 
   Temperature would not be an immediate problem because although space is very cold, a vacuum is a perfect insulator. You would only gradually radiate away your body heat. Exposure to direct sunlight would give you a sunburn. Your saliva and tears would quickly evaporate and you might have eardrum troubles.
   After about 15 seconds, oxygen-deprived blood from the lungs reaches the brain causing you to lose consciousness. 
   At such low pressures, your body fluids will boil away. Moist surfaces such as the eyes, mouth and airways experience this immediately. Fluids inside your body also start to vaporize. This happens rapidly in the lungs and under the skin. Bubbles of water vapor that form in the bloodstream will interrupt the circulation. This is called ebullism. No one knows how long the human body can withstand the vacuum of space—perhaps a couple of minutes. 
   In 1965, this actually happened to Jim LeBlanc while working at the NASA Manned Spacecraft Center (now called the Johnson Space Center). He was testing a space suit in their vacuum chamber when the tube that was pressurizing his suite came loose and his suit was almost completely depressurized within seconds. He stayed conscious for about 14 seconds and they began repressurizing the chamber right after he passed out. After regaining consciousness, he recalled that he could hear and feel the air leaking out of his suit, and the last thing he remembered was the saliva on his tongue starting to boil.

Violet Skies Are for the Birds

I love the XKCD webcomic, especially when it features a science-related theme. Comic number 1145 poses the question “Why isn’t the sky violet?” which I will attempt to answer this week. But first we need to understand why the sky is blue: it’s because of Rayleigh scattering.
   Rayleigh scattering (named after the British scientist Lord Rayleigh) occurs when sunlight passes through the atmosphere and is scattered by air molecules. The light from the sun is a mixture of all the colors of the rainbow, each with its own characteristic wavelength. Sir Isaac Newton demonstrated this nearly 350 years ago by using a prism to separate white light into its different spectral colors.

Rayleigh scattering: blue light is scattered
more strongly than red light as it passes
through the atmosphere and is why the sky
is blue during the day.

   The amount of scattering is inversely proportionate to the fourth power of the light’s wavelength. That means that the shorter-wavelength components of sunlight (blue and violet) are about ten times more strongly scattered than the longer-wavelength components at the red end of the visible spectrum. Rayleigh scattering is responsible for the blue color of the sky during the day and the orange color during sunrise and sunset. It’s also the reason that the sun itself is yellow when overhead and red at sunrise and sunset.
   Now back to the original question: since violet light has an even shorter wavelength than blue light, why does the sky appear blue instead of violet? 
   First, the sun produces a lot more blue light than violet light. The Sun’s spectral peak is in the green range and as the wavelength decreases from blue to violet there is a steep drop-off in intensity.

Solar emission intensity compared to human cone cell responsivity. Both are shown
as a function of wavelength.

   Second and more importantly, even though blue and violet both have short wavelengths, our eyes don’t see violet as well as blue. We have three types of color receptors in our retina, called cone cells. There are short-, medium- and long-wavelength cone cells that respond most strongly to blue, green and red light, respectively. Cone cells are stimulated in different proportions and our brain uses this information to construct the colors we see. Across the visible spectrum, it turns out that blue provides the maximum responsivity.

This image demonstrates how
yellow light can be perceived
as a mixture of red and green
light. Take a few step back from
the monitor to see the effect.

   Since the cone cells are sensitive over broad, overlapping ranges of wavelengths, many colors can be seen by mixing other colors. Take yellow for example. There’s a good reason why caution signs are yellow—yellow light lies right between green and red on the spectrum and causes a large response in both the medium- and long-wavelength cone cells. Regardless of whether you see pure yellow or a mixture of red and green, your eyes can’t tell the difference. When two colors can be created with different spectral distributions they are called metamers. In this same way, the sky’s combination of violet and blue triggers the same cone response as pure blue plus white light, which yields the pale blue color that we see.
   It’s no coincidence that we see things the way we do. Human evolution is shaped by our environment—the ability to separate the colors around us provides an evolutionary advantage. 
   Even though humans don’t see violet in the sky, some birds might because they have an extra type of cone cell that extends their color vision into the ultraviolet range. The male Blue Grosbeak appears mostly blue to humans but has plumage shifted to the UV range that he uses to his advantage during courtship. The Common Kestrel uses its UV-enhanced vision to find voles by following their scent trail which reflects UV light, making it visible to this clever hunter. So maybe violet skies are for the birds.