Science Buds

[kidsneedscience]

Ok, so Pluto’s not a planet.  What about the rest of them?  

This question has troubled scientists and students for decades, and the recent demotion of Pluto from planet to plutoid marked a significant change in how scientists classify planets. In 2006 the International Astromical Union identified three key criteria to classify a body as a planet:  

The body is in orbit around the Sun,

The body has sufficient mass to assume hydrostatic equilibrium (a nearly round shape), and

The body has “cleared the neighbourhood” around its orbit.

By this definition Pluto was excluded, but the discovery of a transneptunian object on January 5, 2005 added very briefly a planet to the solar system.  

Many teams were racing to map the outer solar system, specifically the belt of asteroids and debris in the scattered disc known as transneptunian objects, and the discovery of Eris and Dysnomia took several years of searching, two years of analysis with both computers and good old-fashioned legwork.  The team of Mike Brown, Chad Trujillo, and David Rabinowitz had programmed their computers to rule out objects moving too slowly to count and missed seeing Eris when it was first photographed.  Manually pouring over the photos almost a year and a half later, they found the largest (to date) plutoid or dwarf planet.

Wanting to name more sky objects after women, internally the team referred to the dwarf planet as Xena, after the popular television series.  After a period of several years (and much consensus building) the name Eris was settled on.  Eris was the goddess of strife in Greek mythology, the meddling troublemaker who doomed the marriage of Peleus and Thetis, the parents of Achilles, which led to the disastrous war that destroyed both Troy and much of the invading Greek armies.  Eris’s own son was named Dysnomia, meaning lawlessness, and when the Hubble Space Telescope discovered that Eris had a moon, well, the name was inevitable.  Since the discovery of Eris and Dysnomia, several more plutoids have been discovered, but none yet as large.  Eris was considered a planet for less than a year, before both Eris and Pluto were reclassified as plutoids.  

Images of Eris and Dysnomia courtesy NASA/Hubble.

[sciencebuds]

Nasa records sounds from space.

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Ancient oddball invertebrate finds its place on the tree of life

Hyoliths are evolutionary misfits no more.

This class of ancient marine invertebrates has now been firmly pegged as lophophorates, a group whose living members include horseshoe worms and lamp shells, concludes an analysis of more than 1,500 fossils, including preserved soft tissue.  

The soft-bodied creatures, encased in conical shells, concealed U-shaped guts and rings of tentacles called lophophores that surrounded their mouths. Fossil analysis suggests that hyoliths used those tentacles and spines, called helens, to trawl the seafloor more than 500 million years ago, researchers report online January 11 in Nature.

For years, paleontologists have argued over where on the tree of life these bottom-feeders belonged. Some scientists thought hyoliths were closely related to mollusks, while others thought the odd-looking creatures deserved a branch all their own. This new insight into hyolith anatomy “settles a long-standing paleontological debate,” the researchers write.

In this hyolith fossil specimen, six tentacles of the lophophore feeding organ (right) and two spines called helens (top and bottom) are visible.

ROYAL ONTARIO MUSEUM

via sciencenews

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The XENON100 Dark Matter Project

Recently we came across the news that the XENON100 experiment contradicts suspected dark matter signal from DAMA/LIBRA. So, then the question arises, what are we looking for actually? Also, what has xenon to do with it?

 Well first of all, the very idea of dark matter is hypothetical. It only exists so as to fill up the gaps so that the theory of gravity remains intact, that is to comply with the accelerated expansion of the universe. This is how science has always been, as Richard Feynman once said in one of his lectures, by having confidence in one physical law and yet we find an anomaly in it then it suggests that perhaps some other phenomena exist that fills the missing links. So, our strong confidence in the correctness of the theory of gravity suggested that that there is some unobservable matter out there that corrects the anomaly.

 This led to the beginning of a new quest, to discover the Dark Matter. Over the years several attempts were made, each promising in its own way, yet unsuccessful so far. One of the promising candidates for dark matter are the weakly interactive massive particles, commonly known as WIMP, which again are hypothetical. The WIMP form a class of heavy nonbaryonic particles that interacts slightly with matter ever so lightly by gravity or weak forces.

 If the WIMP idea is correct, billions of these particles pass through your hand every second, and also through the Earth and everything on it. But because WIMPs interact so weakly with ordinary matter, this ghostly traverse goes entirely unnoticed. So far, all the attempts LUX, SuperCDMS, Large hadron colliders, XENON100, all failed to produce a satisfying observation.

The XENON dark matter research project operated at the Italian Gran Sasso laboratory is a deep underground research facility featuring increasingly ambitious experiments aiming to finally detect long sought after dark matter particles. The experiment detects scintillation and ionization produced when particles interact in the liquid xenon volume, to search for an excess of nuclear recoil events over known backgrounds.  XENON100, contains 165 kg of liquid xenon, with 62 kg in the target region and the remaining xenon in an active veto.

In their new analysis, published online January 3 at arXiv.org, XENON100 scientists looked for an annual variation in the rate of blips in their detector, a tank filled with 161 kilograms of liquid xenon. Such a signal could be a hallmark of Earth’s motion through a prevailing wind of dark matter particles as the planet makes its yearly jaunt around the sun. Another dark matter experiment at Gran Sasso, DAMA/LIBRA, claims to have found strong evidence of a yearly modulation, but other experiments have failed to replicate the result.

Scientists combed over four years of data for events that could be caused by dark matter interacting with electrons in XENON100. The researchers found no evidence of an annual cycle, contradicting DAMA’s claim.

Why Xenon? 

Liquid xenon is an attractive target for a sensitive WIMP search. Its high density and high atomic number allow for a compact detector geometry. The high mass of the Xe nucleus is favorable for WIMP scalar interactions, provided a low recoil energy threshold. As detector material LXe has excellent ionization and scintillation properties.

With the simultaneous measurement of charge and light and 3D position resolution, event information can be maximized to achieve effective and redundant background identification and discrimination power, while maintaining most of the target active. Xenon, which contains both odd and even isotopes for coherent and purely spin-dependent WIMP interactions, is available in large quantities. Various techniques have demonstrated ultra-pure LXe in which an electron lifetime in excess of 1ms allows the drift of free electrons over 30 cm and longer.

The reduction of the krypton contamination in natural xenon to the required part per billion level has also been verified with a distillation tower and cold traps.

[sciencebuds]

The Oort Cloud

The Oort Cloud is a theorized shell of icy objects that lie beyond the Kuiper Belt. It lies in the outermost reaches of our solar system. It is named after astronomer Jan Oort, who first theorized its existence.

 The Oort Cloud is roughly spherical, and is thought to be the origin of most of the long-period comets that have been observed.

 This cloud of particles is theorized to be the remains of the disc of material that formed the Sun and planets. Astronomers now refer to those primeval objects as a protoplanetary disk.

 The most likely theory is that the material now in the Oort Cloud probably formed closer to the young Sun in the earliest epochs of solar system formation. As the planets grew, and in particular as Jupiter coalesced and migrated to its present position, its gravitational influence is thought to have scattered many icy objects out to their present position in the Oort cloud.

 The Oort Cloud is very distant from the Sun, the inner limits of the Oort Cloud begin at about 2,000 AU from the Sun and it can be disrupted by the nearby passage of a star, nebula, or by actions in the disk of the Milky Way. Those actions knock cometary nuclei out of their orbits, and send them on a headlong rush toward the Sun.

 The Oort Cloud is a reserve of cometary nuclei that contain ices dating back to the origin of the solar system. No one knows for sure how many objects exist in the Oort Cloud, but most estimates put it at around 2 trillion.

 The existence of Oort cloud is purely hypothetical, it is not visible over a telescope for observation as each object in it is set apart nearly as the distant as earth is from Saturn.

  http://space-facts.com/oort-cloud/

[sciencebuds]

Menotaxis

Ever wondered why you see insects swiveling around light sources at night?

It is a strange yet at times beautiful phenomenon. Many of the insects end up dying doing this all-night long. Although it may seem that they came in search of heat or food, the reality is much more tragic.

It turns out that in most cases this activity is almost completely involuntary. This behavior is known as Menotaxis or transverse orientation and it is an innate function in many insects to guide their path. These insects have light sensitivity cells on their backs. When the sun or moon is above them they can maintain a path parallel to the ground by keeping the light source at 90 degrees.

When humans came up with the light bulb, the insects’ backs started responding to the light from bulb and so they fly in 90 degrees with the light bulb resulting them to revolve around the light.

The same technique is used by certain marine organisms (fishes) to swim upright. They use the sun’s light to keep their body upright in water.

[sciencebuds]

Cryoconite

Cryoconite is powdery dust made of combination of small rock particles, soot and microbes. Why is this guy important ?

Because he is going to play an important role in Climate Change. Well this post is only for the brave who still believe that our climate is changing. 

Cryoconite has been flying through the air and settling down on different parts of the earth for millions of years. 

There is a huge accumulation of it on the Green Land Ice sheet. But most of its covered under fresh white snow which thickens the Ice.

Because of recent melting of the ice sheets these dark coloured ICE DIE has started to show up. Ice plays an important role in reflecting a lot of the Suns rays back and thus decreasing the surface temperature. But as the surface becomes dark they start absorbing heat from the suns rays and this further melts the Ice. This can seriously disrupt the melting and thickening of the ice sheets. 

In fact this has already started happening. On top of that, this year in 2016 the Global Sea Ice Area has not increased as it usually does from October to December, its declining

Links:

https://en.wikipedia.org/wiki/Cryoconite

http://www.smithsonianmag.com/scien...