What is a moonshot?

Moonshots live in the gray area between audacious technology and pure science fiction. Instead of a mere 10% gain, a moonshot aims for a 10x improvement over what currently exists. The combination of a huge problem, a radical solution to that problem, and the breakthrough technology that just might make that solution possible, is the essence of a moonshot.

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The Apollo 17 crew in the Command Module during Translunar Coast, and in lunar orbit.

New Kind of Variable Star Discovered

Astronomers using the Swiss 1.2-metre Euler telescope at ESO’s La Silla Observatory in Chile have found a new type of variable star. The discovery was based on the detection of very tiny changes in brightness of stars in a cluster. The observations revealed previously unknown properties of these stars that defy current theories and raise questions about the origin of the variations.

The Swiss are justly famed for their craftsmanship when creating extremely precise pieces of technology. Now a Swiss team from the Geneva Observatory has achieved extraordinary precision using a comparatively small 1.2-metre telescope for an observing programme stretching over many years. They have discovered a new class of variable stars by measuring minute variations in stellar brightness.

The new results are based on regular measurements of the brightness of more than three thousand stars in the open star cluster NGC 3766 over a period of seven years. They reveal how 36 of the cluster’s stars followed an unexpected pattern — they had tiny regular variations in their brightness at the level of 0.1% of the stars’ normal brightness. These variations had periods between about two and 20 hours. The stars are somewhat hotter and brighter than the Sun, but otherwise apparently unremarkable. The new class of variable stars is yet to be given a name.

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Credit: ESO

C/2012 S1 (ISON) is a sungrazing comet discovered on 21 September 2012 by Vitali Nevski and Artyom Novichonok. The comet will come to perihelion (closest approach to the Sun) on 28 November 2013 at a distance of 0.012 AU (1,800,000 km; 1,100,000 mi) from the center point of the Sun.

Between 5 June and 29 August 2013, comet ISON will have an elongation less than 30 degrees from the Sun. The Spitzer Space Telescope may observe the comet on June 13 and help estimate carbon dioxide production. Around September 2013, it should become bright enough to be visible through small telescopes or binoculars. But the comet is not expected to reach the naked eye magnitude of 6 until November.Assuming it survives perihelion passage, it should be visible to the naked eye until early January 2014.

In October, the comet will pass through the constellation Leo, passing near Leo’s brightest star Regulus and then passing near Mars in the night sky, and these brighter objects might make the comet easier to locate. STEREO should be able to view ISON around 10 October. In November, when the comet is brighter, it will sweep past another bright star in our sky, Spica in the constellation Virgo, and another planet, Saturn. SOHO will be able to view ISON starting 27 November. Around the time the comet reaches its perihelion on 28 November, it may become extremely bright if it remains intact, probably reaching a negative magnitude. It may briefly become brighter than the full Moon.

It is expected to be brightest around the time it is closest to the Sun; however, it may be less than 1° from the Sun at its closest, making it difficult to see against the Sun’s glare. In December, the comet will be growing dimmer, but, assuming that it remains intact, it will be visible from both hemispheres of Earth, possibly with a long tail.

Marks on Martian Dunes May Be Tracks of Dry-Ice Sleds

NASA research indicates hunks of frozen carbon dioxide — dry ice — may glide down some Martian sand dunes on cushions of gas similar to miniature hovercraft, plowing furrows as they go.

Researchers deduced this process could explain one enigmatic class of gullies seen on Martian sand dunes by examining images from NASA’s Mars Reconnaissance Orbiter (MRO) and performing experiments on sand dunes in Utah and California.

The hillside grooves on Mars, called linear gullies, show relatively constant width — up to a few yards, or meters, across — with raised banks or levees along the sides. Unlike gullies caused by water flows on Earth and possibly on Mars, they do not have aprons of debris at the downhill end of the gully. Instead, many have pits at the downhill end.

Images from MRO’s High Resolution Imaging Science Experiment (HiRISE) camera show sand dunes with linear gullies covered by carbon-dioxide frost during the Martian winter. The location of the linear gullies is on dunes that spend the Martian winter covered by carbon-dioxide frost. By comparing before-and-after images from different seasons, researchers determined that the grooves are formed during early spring. Some images have even caught bright objects in the gullies.

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For more about HiRISE, visit: http://hirise.lpl.arizona.edu .

The Origins of the Universe: the Big Bang

The diagram here illustrates the main events occurring in the history of our Universe. The vertical time axis is not linear in order to show early events on a reasonable scale. The temperature rises as we go backwards in time towards the Big Bang and physical processes happen more rapidly. The timescales and temperatures indicated on this diagram span an enormous range.

The Universe began about fourteen billion years ago in a violent explosion; every particle started rushing apart from every other particle in an early super-dense phase. The fact that galaxies are receding from us in all directions is a consequence of this initial explosion and was first discovered observationally by Hubble.

The Copernican or cosmological principle states that the Universe appears the same in every direction from every point in space. It amounts to asserting that our position in the Universe - with respect to the very largest scales - is in no sense preferred. There is considerable observational evidence for this assertion, including the measured distributions of galaxies and faint radio sources, though the best evidence comes from the near-perfect uniformity of the relic cosmic microwave background radiation. This means that any observer anywhere in the Universe will enjoy much the same view as we do, including the observation that galaxies are moving away from them.

The fact that the Universe is expanding - about every point in space - can be a difficult concept to grasp. The analogy of an expanding balloon may be helpful: imagine residing in a curved flatland on the surface of a balloon. As the balloon is inflated, the distance between all neighbouring points grows; the two-dimensional Universe grows but there is no preferred centre.

About 100,000 years after the Big Bang, the temperature of the Universe had dropped sufficiently for electrons and protons to combine into hydrogen atoms, p + e ⇒ H. From this time onwards, cosmic radiation was effectively unable to interact with the background gas; it has propagated freely ever since, while constantly losing energy because its wavelength is stretched by the expansion of the Universe. Originally, the radiation temperature was about 3000 degrees Kelvin, whereas today it has fallen to only 3K.

Observers detecting this radiation today are able to see the Universe at a very early stage on what is known as the ‘surface of last scattering’. Photons in the cosmic microwave background have been travelling towards us for over thirteen billion years, and have covered a distance of about a million billion billion miles.

Prior to about one second after the Big Bang, matter - in the form of free neutrons and protons - was very hot and dense. As the Universe expanded, the temperature fell and some of these nucleons were synthesised into the light elements: deuterium (D – a hydrogen atom with a neutron and a proton inside its nucleus), helium-3 (helium with only one neutron in its nucleus), and helium-4. Theoretical calculations for these nuclear processes predict, for example, that about a quarter of the Universe consists of helium-4, a result which is in good agreement with current stellar observations.

The heavier elements, of which we are partly made, were created later in the interiors of stars and spread widely in supernova explosions.

The standard Hot Big Bang model also provides a framework in which to understand the collapse of matter to form galaxies and other large-scale structures observed in the Universe today. At about 10,000 years after the Big Bang, the temperature had fallen to such an extent that the energy density of the Universe began to be dominated by massive particles, such as protons, neutrons and electrons, rather than the light and other radiation which had predominated earlier. This change in the form of the main matter density meant that the gravitational forces between the massive particles could begin to take effects, so that any small perturbations in their density would grow. Over ten billion years later we see the results of this collapse.

Despite the self-consistency and remarkable success of the standard Hot Big Bang model in describing the evolution of the Universe back to only one hundredth of a second, a number of unanswered questions remain regarding the initial state of the Universe.

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Successful start to China’s fifth human spaceflight

Three Chinese astronauts, led by a veteran of a previous space mission, soared into orbit Tuesday to begin a 15-day voyage to China’s Tiangong 1 space lab, a flight officials say will expand the capabilities of the country’s manned space program.

The 191-foot-tall Long March 2F rocket, powered by 1.4 million pounds of thrust, lifted off at 0938 GMT (5:38 a.m. EDT; 5:38 p.m. Beijing time) from the Jiuquan space base in northwest China’s Inner Mongolia autonomous region.

Less than 10 minutes later, after a dazzling launch broadcast on Chinese state television, the 8.5-ton Shenzhou 10 capsule arrived in orbit. A few moments later, the spacecraft extended its two solar array wings to generate electricity.

These images were taken from the official CCTV broadcast of the launch, showing views from cameras from both the ground and on-board the rocket. The images show liftoff, separation of the launcher’s emergency escape tower, jettison of the Long March’s first stage and four liquid-fueled boosters, and deployment of the solar arrays.

Photo credit: CCTV/Spaceflight Now

Bill Nye and Neil deGrasse Tyson on Stargate: Atlantis. (S05E16 )

Bill Nye narrates this short film on the basics of climate change.

The science is settled. Our planet is heating up, and carbon pollution from Dirty Energy is to blame. The fossil fuel industry burns oil, coal and gas, sending heat-trapping emissions into the air. Ninety million tons of carbon pollution enters the atmosphere every day. That means a hotter world for all of us. It also leads to Dirty Weather, from extreme rainstorms to prolonged drought.

Nine of the ten hottest years on record were in the past twelve years. Just in recent months, extreme rainfall and floods have affected us everywhere from the Mississippi Valley to Beijing. Superstorm Sandy both devastated human lives and led to tens of billions of dollars in damages. The most severe drought in decades spread over half the United States. Climate change is already happening, and it has entered our daily lives.

For more information: http://ClimateRealityProject.org

Young White Dwarfs on the Fast Track

These images show young and old white dwarf stars — the burned-out relics of normal stars — in the ancient globular star cluster NGC 6397.

The image above, taken by a ground-based telescope, shows the dense swarm of hundreds of thousands of stars that make up the globular cluster. The white box outlines the location of the observations made by NASA’s Hubble Space Telescope.

The close-up image below, taken by Hubble’s Advanced Camera for Surveys, reveals young white dwarfs less than 800 million years old and older white dwarfs between 1.4 and 3.5 billion years old. The Hubble researchers distinguished the younger from the older white dwarfs based on their color and brightness. The younger white dwarfs are hotter and therefore bluer and brighter than the older ones.

The astronomers were surprised to find young white dwarfs far away from the cluster’s core. They had assumed that the youngsters would reside at the center and migrate over time to the cluster’s outskirts. The astronomers proposed that the cluster stars that burn out as white dwarfs are given a boost that propels them to the edge of the cluster.

Credit: NASA, ESA, and H. Richer (University of British Columbia)

Blue Straggler Stars in the Galactic Bulge

Peering deep into the star-filled, ancient hub of our Milky Way (left), the Hubble Space Telescope has found a rare class of oddball stars called blue stragglers, the first time such objects have been detected within our galaxy’s bulge.

Blue stragglers — so named because they seem to be lagging behind in their rate of aging compared with the population from which they formed — were first found inside ancient globular star clusters half a century ago.

This discovery is a spin-off from a seven-day-long survey conducted in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble peered at and obtained variability information for 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away. The picture at right shows the 42 blue straggler candidates circled in green.

Blue stragglers have long been suspected to be located in the bulge. Until now, it has never been proven because younger stars in the disk of our galaxy lie along the line-of-sight to the core, confusing and contaminating the view. But Hubble’s view is so sharp that astronomers could distinguish the motion of the core population from foreground stars in the Milky Way.

It’s not clear how blue stragglers form, or if there is more than one mechanism at work. A common idea is that two stars collide and merge. This stirs up hydrogen fuel and causes the resulting, more massive star to undergo nuclear fusion at a faster rate, causing it to burn hotter and bluer.

Credit: NASA, ESA, W. Clarkson (Indiana University and UCLA), and K. Sahu (STScI)

Boris, my pet snail roaming around the Christmas Tree Cluster, near the Cone Nebula.

Earth’s Twin Seen From Saturn

Peering over the shoulder of giant Saturn, through its rings, and across interplanetary space, NASA’s Cassini spacecraft spies the bright, cloudy terrestrial planet, Venus. The vast distance from Saturn means that Venus only shows up as a white dot, just above and to the right of the image center.

Venus, along with Mercury, Earth, and Mars, is one of the rocky ‘terrestrial’ planets in the solar system that orbit relatively close to the sun. Though Venus has an atmosphere of carbon dioxide that reaches nearly 900 degrees Fahrenheit (500 degrees Celsius) and a surface pressure 100 times that of Earth, it is considered a twin to our planet because of their similar size, mass, rocky composition and orbit. Venus is covered in thick sulfuric acid clouds, making it very bright.

The bright arc is the limb of Saturn. A portion of the rings is seen in silhouette against the face of Saturn, which itself is faintly illuminated by sunlight scattered off the rings.

Credit: NASA/JPL-Caltech/Space Science Institute

Peeking at Saturn

Cassini peers around the hazy limb of Titan to spy the sunlit south pole of Saturn in the distance beyond.

The thick, smog-like atmosphere of frigid Titan (5,150 kilometers, 3,200 miles across) is a major source of interest for the Cassini mission.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The image was taken with the Cassini spacecraft narrow-angle camera on Dec. 26, 2005 at a distance of approximately 26,000 kilometers (16,000 miles) from Titan. Image scale is 1 kilometer (4,643 feet) per pixel.

Credit: NASA/JPL/Space Science Institute

Cassini Sees Precursors to Aerosol Haze On Saturn’s Largest Moon, Titan

Scientists working with data from NASA’s Cassini mission have confirmed the presence of a population of complex hydrocarbons in the upper atmosphere of Saturn’s largest moon, Titan, that later evolve into the components that give the moon a distinctive orange-brown haze. The presence of these complex, ringed hydrocarbons, known as polycyclic aromatic hydrocarbons (PAHs), explains the origin of the aerosol particles found in the lowest haze layer that blankets Titan’s surface. Scientists think these PAH compounds aggregate into larger particles as they drift downward.

Of all the bodies in the solar system, Saturn’s largest moon, Titan, has the atmosphere most resembling that of Earth. Like that of our planet, Titan’s atmosphere is largely composed of molecular nitrogen. Unlike Earth’s atmosphere, however, Titan’s contains only small traces of oxygen and water. Another molecule, methane, plays a similar role to that of water in Earth’s atmosphere, and makes up about 2 percent of Titan’s atmosphere. Scientists have speculated that the atmosphere of this moon may resemble that of our planet in its early days, before primitive living organisms enriched it with oxygen via photosynthesis.

When sunlight or highly energetic particles from Saturn’s magnetic bubble hit the layers of Titan’s atmosphere above about 600 miles (1,000 kilometers), the nitrogen and methane molecules there are broken up. This results in the formation of massive positive ions and electrons, which trigger a chain of chemical reactions, producing a variety of hydrocarbons — a wide range of which have been detected in Titan’s atmosphere. These reactions eventually lead to the production of carbon-based aerosols, large aggregates of atoms and molecules that are found in the lower layers of the haze that enshrouds Titan, well below 300 miles (500 kilometers). The process is similar to Earth, where smog starts with sunlight breaking up hydrocarbons that are emitted into the air. The resulting pieces recombine to form more complex molecules.

Aerosols in Titan’s lower haze have been studied using data from the descent of the European Space Agency’s Huygens probe, which reached the surface in 2005, but their origin remained unclear. New studies analyzing data from Cassini’s visual and infrared mapping spectrometer (VIMS) gathered in July and August 2007 might solve the problem. One new study of Titan’s upper atmosphere in the Astrophysical Journal describes the detection of the PAHs, which are large carbon-based molecules that form from the aggregation of smaller hydrocarbons.

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Credit: ESA/ATG medialab/ScienceDaily