Marijuana & “Exo-Earth” | SciByte 127

Posted on: April 22, 2014

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Marijuana & “Exo-Earth” | SciByte 127

We take a look at marijuana\’s effect on the brain, an \”Earth-like\” exoplanet, the brains distraction controls, a possible new moon for Saturn, spacecraft updates, Curiosity news, and as always take a peek back into history and up in the sky this week.

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Show Notes:

Marijuana’s and Changes to the Brain

  • Young adults who used marijuana only recreationally showed significant abnormalities in two key brain regions that are important in emotion and motivation
  • The Study
  • This is the first study to show casual use of marijuana is related to major brain changes
  • Through different methods of neuroimaging, scientists examined the brains of young adults ages 18 to 25, from Boston-area colleges; 20 who smoked marijuana and 20 who didn\’t. Each group had nine males and 11 females
  • The users underwent a psychiatric interview to confirm they were not dependent on marijuana
  • The changes in brain structures indicate the marijuana users\’ brains are adapting to low-level exposure to marijuana
  • Results
  • The degree of brain abnormalities in these regions is directly related to the number of joints a person smoked per week, the more joints a person smoked, the more abnormal the shape, volume and density of the brain regions
  • Some of these people only used marijuana to get high once or twice a week thinking a little recreational use shouldn\’t cause a problem; however, data directly says this is not the case
  • Scientists examined the nucleus accumbens and the amygdala-key regions for emotion and motivation, and associated with addiction-in the brains of casual marijuana users and non-users
  • Researchers analyzed three measures: volume, shape and density of grey matter to obtain a comprehensive view of how each region was affected.
  • Both these regions in recreational pot users were abnormally altered for at least two of these structural measures and the degree of those alterations was directly related to how much marijuana the subjects used
  • What is Means
  • The study results fit with animal studies that show when rats are given tetrahydrocannabinol (THC) their brains rewire and form many new connections. THC is the mind-altering ingredient found in marijuana
  • Think when people are in the process of becoming addicted, their brains from these new connections
  • In animals, these new connections indicate the brain is adapting to the unnatural level of reward and stimulation from marijuana. These connections make other natural rewards less satisfying
  • The brain changes suggest that structural changes to the brain are an important early result of casual drug use
  • Researchers did not know the THC content of the marijuana, which can range from 5 to 9 percent or even higher, the THC content is much higher today than the marijuana during the 1960s and 1970s, which was often about 1 to 3 percent
  • Further Reading / In the News

— NEWS BYTE —

Another Earth-sized Exo-Planet

  • The first Earth-sized exoplanet orbiting within the habitable zone of another star has been confirmed by observations with both the W. M. Keck Observatory and the Gemini Observatory
  • The initial discovery, made by NASA\’s Kepler Space Telescope, is one of a handful of smaller planets found by Kepler and verified using large ground-based telescopes
  • The System
  • The host star, Kepler-186, is an M1-type dwarf star relatively close to our solar system, at about 500 light years and is in the constellation of Cygnus
  • The star is very dim, being over half a million times fainter than the faintest stars we can see with the naked eye and is cooler than the Sun
  • Five small planets have been found orbiting this star, four of which are in very short-period orbits and are very hot
  • This Earth-sized planet, one of five orbiting this star, which is cooler than the Sun, resides in a temperate region where water could exist in liquid form
  • Observations
  • Neither Kepler (nor any telescope) is currently able to directly spot an exoplanet of this size and proximity to its host star all they can do is eliminate essentially all other possibilities so that the validity of these planets is really the only viable option
  • With such a small host star, the team employed a technique that eliminated the possibility that either a background star or a stellar companion could be mimicking what Kepler detected
  • Differential Speckle Survey Instrument (DSSI)
  • The team obtained extremely high spatial resolution observations from the eight-meter Gemini North telescope on Mauna Kea in Hawaii using a technique called speckle imaging, as well as adaptive optics (AO) observations from the ten-meter Keck II telescope
  • The Gemini \”speckle\” data directly imaged the system to within about 400 million miles (about 4 AU, approximately equal to the orbit of Jupiter in our solar system) of the host star and confirmed that there were no other stellar size objects orbiting within this radius from the star
  • It works on a principle that utilizes multiple short exposures of an object to capture and remove the noise introduced by atmospheric turbulence producing images with extreme detail
  • The System
  • Kenny MacLeod ‏@siabost9deas
  • Multimedia
  • YouTube | Kepler-186f : First Earth-size Planet Discovered in the Habitable Zone of Another Star [HD] | The Mars Underground
  • Further Reading / In the News
  • First potentially habitable Earth-sized planet confirmed: It may have liquid water | Phys.org

— TWO-BYTE NEWS —

The Brains Distraction Control

  • A new study to reveals that our brains rely on an active suppression mechanism to avoid being distracted by salient irrelevant information when we want to focus on a particular item or task
  • This discovery opens up the possibility that environmental and/or genetic factors may hinder or suppress a specific brain activity that the researchers have identified as helping us prevent distraction.
  • These results show clearly that this is only one part of the equation and that active suppression of the irrelevant objects is another important part
  • Psychologists say their discovery could help scientists and health care professionals better treat individuals with distraction-related attentional deficits
  • Distraction is a leading cause of injury and death in driving and other high-stakes environments
  • Disorders associated with attention deficits, such as ADHD and schizophrenia, may turn out to be due to difficulties in suppressing irrelevant objects rather than difficulty selecting relevant ones
  • Researchers are now turning their attention to understanding how we deal with distraction and why we can\’t suppress potentially distracting objects, whether some of us are better at doing so and why that is the case.
  • Further Reading / In the News
  • ADHD: Scientists discover brain\’s anti-distraction system | ScienceDaily

A New Moon for Saturn?

  • A bright clump spotted orbiting Saturn at the outermost edge of its A ring may be a brand new moon in the process of being born
  • The effects of this now 1,200-kilometer-long, 10-kilometer-wide arc of icy material were first seen in May 2012 traveling along the edge of the A ring
  • The arc is thought to be the result of gravitational perturbations caused by an as-yet unseen embedded object about a kilometer wide – possibly a miniature moon in the process of formation
  • The half-mile-wide object has been unofficially named “Peggy,” eventually it may coalesce into a slightly larger moon and move outward, establishing its own orbital path around Saturn
  • This is how many of Saturn’s other moons are thought to have formed much further back in the planet’s history
  • While it is possible that the bright perturbation is the result of an object’s breakup rather than formation, researchers are still looking forward to finding out more about its evolution.
  • Further Reading / In the News
  • Is Saturn Making a New Moon? | UniverseToday.com
  • NASA Cassini Images May Reveal Birth of New Saturn Moon | NASA.gov
  • NASA Cassini Missiom Page

— SPACECRAFT UPDATE—

SpaceX Dragon Delivery Mission

New Horizons and Questions About Pluto

  • Compositional Model Theories
  • Two space researchers have published a paper where they describe three possible interior models of the former planet Pluto
  • The possibilities include: an undifferentiated rock/ice mixture, a differentiated rock/ice mixture, and an ocean covered with ice, the third possibility suggests the likelihood, they claim, of tectonic action on the dwarf planet
  • Scientists believe that Pluto came to exist as it does today, in part due to a collision billions of years ago that led also to the formation of its moon Charon
  • When celestial bodies collide, not only do they knock each other around, they produce heat—heat, the researchers suggest that could still be evident today
  • A theory that suggests that shortly after impact, Pluto and Charon were much closer together where the gravity attraction between them would have caused both to be egg shaped.
  • As time passed, melted ice from the impact would have created an icy crust on top of an ocean on Pluto
  • As Charon moved farther away, the attractive pull would have diminished, causing ice plates to form and crack against one another, a form of tectonics.
  • If that were the case, the two add, then in all likelihood, when New Horizons begins sending back images, they should see evidence of such tectonic action—plate edges thrust into the air
  • Pluto circles the sun in an elliptical orbit, thus sometimes it\’s much closer to the sun than other times, when near, it has a defined atmosphere, when far away however, its atmosphere actually freezes to its surface
  • Something that could hide ridges in the ice and thus evidence of both tectonic activity and an ocean beneath the crust of ice
  • New Horizons will arrive during a time when its atmosphere is frozen to the surface, it might be difficult to determine which of the three proposed models actually describes the relationship between its exterior and interior
  • Further Reading / In the News
  • Research pair offer three possible models of Pluto ahead of New Horizons visit | Phys.org
  • New Horizons | NASA

— CURIOSITY UPDATE —

  • New Science Location
  • Scientists using NASA\’s Curiosity Mars rover are eyeing a rock layer surrounding the base of a small butte, called \”Mount Remarkable,\” as a target for investigating with tools on the rover\’s robotic arm
  • The butte stands about 16 feet (5 meters) high. Curiosity\’s science team refers to the rock layer surrounding the base of Mount Remarkable as the \”middle unit\” because its location is intermediate between rocks that form buttes in the area and lower-lying rocks that show a pattern of striations
  • Depending on what the mission scientists learn from a close-up look at the rock and identification of chemical elements in it, a site on this middle unit may become the third rock that Curiosity samples with its drill
  • Multimedia
  • Image Galleries at JPL and Curiosity Mulimedia
  • Social Media
  • Curiosity Rover @MarsCuriosity
  • Further Reading / In the News
  • NASA Mars Orbiter Spies Rover Near Martian Butte | mars.jpl.nasa.gov

SCIENCE CALENDAR

Looking back

  • April 25, 1990 : 24 years ago : Hubble Space Telescope : In 1990, the $2.5 billion Hubble Space Telescope was deployed in space from the Space Shuttle Discovery into an orbit 381 miles above Earth. It was the first major orbiting observatory, named in honour of American astronomer, Edwin Powell Hubble. It was seven years behind schedule and nearly $2 billion over budget. In orbit, the 94.5-in primary mirror was found to be flawed, giving blurred images and reduced ability to see distant stars. However, correcting optics were successfully installed in 25 Dec 1993. The telescope 43-ft x 14-ft telescope now provides images with a clarity otherwise impossible due to the effect of the earth\’s atmosphere. Instrument packages capture across the electromagnetic spectrum.

Looking up this week

  • Solar Eclipse
  • On April 29th, an annular solar eclipse occurs over a small D-shaped 500 kilometre wide region of Antarctica
  • 2014 has the minimum number of eclipses possible in one year, with four: two partial solars and two total lunars
  • This month’s solar eclipse is also a rarity in that it’s a non-central eclipse with one limit, where the center of the Moon’s shadow – known as the antumbra during an annular eclipse – will juuuust miss the Earth and instead pass scant kilometres above the Antarctic continent
  • Out of 3,956 annular eclipses occurring from 2000 BCE to 3000 AD, only 68 (1.7%) are of the non-central variety
  • An annular eclipse occurs when the Moon is too distant to cover the disk of the Sun, resulting in a bright “annulus” or “ring-of-fire” eclipse
  • Several southern Indian Ocean islands and all of Australia will still witness a fine partial solar eclipse from this event, a scattering of islands in the southern Indian Ocean will see a 55% eclipsed Sun.
  • In Australia, Perth will see a 55% eclipsed Sun and Sydney will be able to see a 50% partial eclipse low to the horizon in west at sunset
  • Don\’t Forget to Use Safe Viewing Practices
  • The safest way | Pinhole camera/projector and telescope — pinhole projector
  • Optical Filters | Eclipse glasses, welder\’s goggles rated at 14
  • Multimedia
  • YouTube | Safely See the Sun — Build a Shoebox Pinhole Camera | VideoFromSpace
  • YouTube | The April 29th, 2014 Annular Eclipse: Sims from Space | astroguyz
  • Further Reading / In the News

  • Our Guide to the Bizzare April 29th Solar Eclipse UniverseToday.com

  • Keep an eye out for …

  • Fri, April 25 | Dawn | The thin crescent Moon is low in the E and left of Venus
  • Planets
  • Venus | \”Morning Star\” | Look to the E-SE as daylight approached
  • Mars | Just past opposition you can see it most of the night. In the evening is is in the SW with Spica below it, both will be at their highest point around local 12pm DST moving towards the NE as dawn approaches
  • Jupiter | Twilight | High in the SW sinking towards the W horizon as the night progresses

  • Saturn | End of Twilight | Highest in the S around 2am

  • Further Reading and Resources

  • Sky&Telescope
  • SpaceWeather.com
  • StarDate.org
  • For the Southern hemisphere: SpaceInfo.com.au
  • Constellations of the Southern Hemisphere : astronomyonline.org
  • Royal Astronomical Society of New Zealand : rasnz.org.nz
  • AstronomyNow
  • HeavensAbove

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