Planets & Feedback | SciByte 26

Posted on: December 21, 2011

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Planets & Feedback | SciByte 26

We take a look at some of your feedback and questions concerning the sun, solar cells, and even Space Camp. We will also look at the news about some new extra-solar planets, black holes and as always take a peek back into history and up in the sky this week.

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*— FEEDBACK — *

Questions about the sun

  • If the sun can’t fuse gold and such why are they there?
  • Do scientists take these into account with calculating life of the sun?
  • Do they account for them with the weight of the sun?
  • Should we look to Mercury Venus for heavier elements?
  • Formation of the Solar System
  • Throughout the galaxy there are dust clouds containing mostly Hydrogen and heavier elements
  • The heavier elements are from the cores of Type II super nova, when they explode they seed the surrounding areas with those heavier elements
  • The cloud will start contracting, eventually forming a star with a surrounding dust cloud
  • The Sun
  • The sun is 4.5 billion year old main sequence star
  • It has converted about half of the hydrogen in its core into helium, so it still has about 5 billion years before the hydrogen runs out.
  • Each second, more than four million metric tons of matter are converted into energy within the Sun’s core, producing neutrinos and solar radiation
  • The sun manufactures elements from lighter ones in the process of nuclear fusion. Helium is a byproduct of nuclear fusion, and beryllium, lithium, boron, and other atoms are part of the ordinary fusion process.
  • Planets
  • The inner Solar System, the region of the Solar System inside 4 AU, was too warm for volatile molecules like water and methane to condense, so the planetesimals that formed there could only form from compounds with high metals (like iron, nickel, and aluminium) and rocky silicates.
  • These compounds are quite rare in the universe, comprising only 0.6% of the mass of the nebula, so the terrestrial planets could not grow very large
  • The composition of the inner planets are very similar, as are the compositions of the asteroids in the asteroid belt
  • * Of Note*
  • Mining other inner planets for metals might be feasible if we were able to safely travel there and back, and for less money that would require to aquire it on Earth
  • Another reason to mine other inner planets would be to increase the supplies of rare metals on Earth
  • Multimedia
  • YouTube VIDEO :Naked Science: Birth of the Solar System
  • YouTube VIDEO : Moon Formation Annimation
  • VIDEO : The Composition of the Sun @ NASA.gov
  • IMAGE : Hubble image of protoplanetary discs
  • Further Reading / In the News
  • Hubble Confirms Abundance of Protoplanetary Disks around Newborn Stars @ https://hubblesite.org
  • Formation of the Solar System @ universetoday.com

From Twitter : First Solar Cell to break the rules?

  • A Twitter follower pointed out this story
  • The low down
  • Researchers from the National Renewable Energy Laboratory (NREL) have reported the first solar cell that produces a photocurrent that has an external quantum efficiency greater than 100 percent when photoexcited with photons from the high energy region of the solar spectrum.
  • Quantum efficiency for photocurrent, usually expressed as a percentage, is the number of electrons flowing per second in the external circuit of a solar cell divided by the number of photons per second of a specific energy (or wavelength) that enter the solar cell
  • Significance
  • The company’s tiny solar cells, each a dot the size of a ballpoint pen tip, have been validated to convert 41 percent of solar energy to electricity
  • They can grow a tiny semiconductor on a substrate and then a machine transfers those cells to a wafer.
  • Additional layers are automatically added to the wafer so that a very efficient, triple-junction solar cell is constructed
  • Quantum dots, by confining charge carriers within their tiny volumes, can harvest excess energy that otherwise would be lost as heat – and therefore greatly increase the efficiency of converting photons into usable free energy.
  • The semiconductor printing technique can be used for many applications, including improving LED lighting performance, better hard drives, or sensors for medical device.
  • The company that was chosen to build concentrating photovoltaic (CPV) collector that uses lenses to concentrate light 1,000 times onto its tiny solar cells.
  • The mechanism for producing a quantum efficiency above 100 percent with solar photons is based on a process called Multiple Exciton Generation (MEG)
  • Multiple Exciton Generation (MEG) is where a single absorbed photon of appropriately high energy can produce more than one electron-hole pair per absorbed photon.
  • The first built concentrating photovoltaic (CPV) collector that uses lenses to concentrate light 1,000 times onto its tiny solar cells
  • Photons of different colors have different amounts of energy. In the visible spectrum, reds and oranges have less energy, while blues, violets, and ultraviolet photons carry progressively more.
  • When high-energy photons hit a semiconducting material in a solar cell, they give up this energy to the semiconductor’s electrons, exciting them from a static position so that they are able to conduct.
  • In many cases, high-energy photons—violets and ultraviolets—carry far more energy than is needed to give electrons the nudge to conduct. But this excess energy is lost as heat.
  • These solar cells captures some of the excess energy in sunlight normally lost as heat.
  • * Of Note*
  • The key in making the device, Nozik says, was coming up with a recipe for chemically synthesizing and then processing quantum dots.
  • When synthesized, the dots—which are clusters of lead and selenium about 5 nanometers in diameter—end up decorated with long organic molecules that prevent separate dots from clumping together.
  • The company’s target to build a system that generates electricity at under 10 cents per kilowatt hour
  • Further Reading / In the News
  • Peak External Photocurrent Quantum Efficiency Exceeding 100% via MEG in a Quantum Dot Solar Cell Abstract @ sciencemag.org
  • Scientists report first solar cell producing more electrons in photocurrent than solar photons entering cell @ physorg.com
  • Tiny solar cell dots printed for powerful array @ news.cnet.com
  • Solar Cells Capture Lost Energy @ news.sciencemag.orgSolar Cells Capture Lost Energy @ news.sciencemag.org
  • Tiny solar cell could make a big difference @ physorg.com
  • NREL Scientists Report First Solar Cell Producing More Electrons In Photocurrent Than Solar Photons Entering Cell @ nrel.gov

Space Camp, only for the cool kids

*— THE NEWS — *

Earth sized planets discovered!

*— NEWS BYTE — *

Smallest Black hole

  • The low down
  • Black holes reside at the centres of galaxies and swallow everything that falls into their gravitational clutches such that nothing, not even light, can escape.
  • The largest supermassive black holes, capable of swallowing our Solar System whole several times over, were reported just last week
  • Significance
  • Scientists have now found a black hole that could represent the lower boundary for a black hole’s mass at just three solar masses.
  • The distinct pattern of X-ray emission, which resembles the pattern printed on an electrocardiogram in response to a heartbeat
  • * Of Note*
  • That there are only two possibilities to explain the differences: either the new source is farther away or its mass is lower
  • There is a limit to how distant it could be as it would be very unlikely to have it lying outside our Galaxy.
  • In addition the fact that its ‘heart’ beats faster is compatible with a lower mass
  • Multimedia
  • YouTube VIDEO : NASA | RXTE Detects ‘Heartbeat’ Of Smallest Black Hole Candidate
  • Further Reading / In the News
  • NASA’s RXTE Detects ‘Heartbeat’ of Smallest Black Hole Candidate @ nasa.gov
  • Smallest black hole just a heartbeat @ astronomynow.com

Plant-eating dinosaur discovered in Antarctica

  • The low down
  • For the first time, the presence of large bodied herbivorous dinosaurs, Sauropoda, in Antarctica has been recorded.
  • Sauropoda is the second most diverse group of dinosaurs, with more than 150 recognized species.
  • Significance
  • The team’s identification of the remains of the sauropod dinosaur suggests that advanced titanosaurs (plant-eating, sauropod dinosaurs) achieved a global distribution at least by the Late Cretaceous
  • The Cretaceous Period spanned 99.6–65.5 million years ago, and ended with the extinction of the dinosaurs.
  • A detailed description of an incomplete middle-tail vertebra its distinctive ball and socket articulations, lead the authors to identify it as an advanced titanosaur.
  • * Of Note*
  • Until now, remains of sauropoda had been recovered from all continental landmasses, except Antarctica.
  • Other important dinosaur discoveries have been made in Antarctica in the last two decades.
  • Multimedia
  • [IMAGE : Pictures and drawings of what was found @ sciencedaily.com(https://images.sciencedaily.com/2011/12/111219102054-large.jpg)
  • Further Reading / In the News
  • Plant-eating dinosaur discovered in Antarctica @ physorg.com
  • Plant-Eating Dinosaur Discovered in Antarctica @ sciencedaily.com

Comet Lovejoy survives it close encounter with the sun

SPACECRAFT UPDATE

  • * Last time on SciByte*
  • SciByte 22-Nov 22
  • SciByte 23-Nov 30
  • The low down
  • Launch Date: Nov. 26, 2011
  • On Earth it weights roughly 1,982 lbs [899 kg]
  • On Mars is will weight roughly 743 lbs [337 kg]
  • Mars it will weigh 3/8 that due to the lower gravity)
  • That first of six planned course adjustments had originally been scheduled for Nov. 26. The correction maneuver will not be performed until later in December or possibly January.
  • Landing scheduled for : Aug 6, 2012
  • * Of Note*
  • Already 32 million miles from Earth on its interplanetary trek to Mars, the Curiosity rover has begun collecting useful scientific data about the radiation conditions that astronauts would encounter on the way to the red planet.
  • The Radiation Assessment Detector, an instrument mounted the rover, has begun obtaining measurements on energetic particles penetrating the Mars Science Laboratory spacecraft.
  • The device, about the size of a coffee can and weighing 3.8 pounds, was powered up and started gathering data on Dec. 6, some two weeks ahead of schedule. It will downlink data every 24 hours.
  • Scientists are seeing, even inside the spacecraft, about four times higher doses of radiation than the baseline we measured on the launch pad.
  • RAD was designed for the science mission to characterize radiation levels on the surface of Mars, but an important secondary objective is measuring the radiation on the almost nine-month journey through interplanetary space, to prepare for future human exploration
  • Social Media
  • Facebook page for NASA’s Curiosity Mars Rover
  • Twitter for Curiosity Rover @MarsCuriosity
  • Further Reading
  • Where in the solar system is Curiosity? @ nasa.gov
  • Mars Science Laboratory rover page @ nasa.gov
  • Course Excellent, Adjustment Postponed @ nasa.gov
  • NASA Launches Most Capable and Robust Rover to Mars @ nasa.gov

Of Note

SCIENCE CALENDER

Looking back

  • Dec 25 1758 – 253 years ago – predicted return of Halley’s comet : Clear records of the comet’s appearances were made by Chinese, Babylonian, and medieval European chroniclers dating back to 240 BC. It was not until 1705 that Edmund Halley hypothesized that a number of the observation were the same comet. He predicted it would return in 75.5 years and in 1758 it was first sighted by German farmer and amateur astronomer, Johann Georg Palitzsch. Halley’s orbital period over the last three centuries has been between 75 and 76 years, though it has varied between 74 and 79 years. It also has a retrograde orbit, orbiting in the opposite direction of the planets. It’s shape if vaguely resembles a peanut and measures 9.3 x 4.9 x 4.9 mi [15x8x8 km]. Halley’s comet last appeared in the inner Solar System in 1986 and will next appear in mid–2061.
  • Dec 22 1938 – 73 years ago – First coelacanth (re)discovered : Marjorie Courtenay-Latimer, curator of the museum of East London, South Africa, discovered the fish among the catch of a local fisherman. She spotted an unusual 5-ft fish in his “trash” fish pile, believed to have been extinct since the end of the Cretaceous period (145.5 to 65.5 million years) The coelacanth was pale mauvy-blue with iridescent silver markings, and they can grow up to 5.9 ft [1.8 m.] The heart of the coelacanth is shaped differently than most modern fish and its structure is that of a straight tube. The coelacanth braincase is 98.5% filled with fat; only 1.5% of the braincase actually contains any brain.Since 1938, Latimeria chalumnae have been found in the Comoros, Kenya, Tanzania, Mozambique, Madagascar, and in iSimangaliso Wetland Park, Kwazulu-Natal in South Africa. YouTUBE Video
  • Dec 23 1986 – 25 years ago – Voyager – first non-stop, round- the- world flight without refueling : It was piloted by Dick Rutan and Jeana Yeager and took off from Edwards Air Force Base in California on December 14, 1986. It flew easterly 24,986 mi [40,211 lm] in a little over 9 days, 3 minutes and on Dec 23 in completed the first non-stop, round- the- world flight without refueling. A cockpit was only roughly the size of a phone booth, which complicated the flight and sleep rotation of the pilots. It returned safely to Edwards Air Force Base in California after travelling 24,986 miles in 216 hours, at an average speed of 115.8 mph.This has since been accomplished only one other time, by Steve Fossett in the Global Flyer. YouTube VIDEO

Looking up this week

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