Thursday, May 5, 2016

What Causes Air Pollution?

What Causes Air Pollution?:



Carbon dioxide in Earth's atmosphere if half of global-warming emissions are not absorbed. Credit: NASA/JPL/GSFC


By definition, pollution refers to any matter that is "out of place". In other words, it is what happens when toxins, contaminants, and other harmful products are introduced into an environment, disrupting its normal patterns and functions. When it comes to our atmosphere, pollution refers to the introduction of chemicals, particulates, and biological matter that can be harmful to humans, plants and animals, and cause damage to the natural environment.Whereas some causes of pollution are entirely natural - being the result of sudden changes in temperature, seasonal changes, or regular cycles - others are the result of human impact (i.e. anthropogenic, or man-made). More and more, the effects of air pollution on our planet, especially those that result from human activity, are of great concern to developers, planners and environmental organizations, given the long-term effect they can have.By composition, Earth's atmosphere is made up of nitrogen gas (78%), oxygen gas (21%), and other trace gases (such as argon and carbon dioxide). This balance is essential to all life here on Earth, so the introduction of pollutants can have a profound and damaging effect. All told, pollution can take many forms, like carbon compounds such as carbon monoxide (CO) and carbon dioxide (CO²). sulfuric compounds like sulfur dioxide (SO²), methane, radioactive decay, or toxic chemicals.In addition, air pollution can be divided into Primary and Secondary types of pollutants. Whereas primary pollutants are caused by primary sources - i.e. the direct result of processes (such as industrial emissions or volcanic eruptions ) - secondary pollutants are the results of intermingling and reactions by primary pollutants (such as carbon emissions and water vapor, which creates smog).

Natural Causes:

Natural forms of pollution are those that result from naturally-occurring phenomena. This means they are caused by periodic activities that are not man-made or the result of human activity. What's more, these sources of pollution are subject to natural cycles, being more common under certain conditions and less common under others. Being part of Earth's natural climatic variations also means that they are sustainable over long periods of time.Dust and Wildfires: In large areas of open land that have little to no vegetation, and are particularly dry due to a lack of precipitation, wind can naturally create dust storms. This particulate matter, when added to the air, can have a natural warming effect and can also be a health hazard for living creatures. Particulate matter, when scattered into regions that have natural vegetation, can also be a natural impediment to photosynthesis.Wildfires are a natural occurrence in wooded areas when prolonged dry periods occur, generally as a result of season changes and a lack of precipitation. The smoke and carbon monoxide caused by these fires contribute to carbon levels in the atmosphere, which allows for greater warming by causing a Greenhouse Effect.Animal and Vegetation: Animal digestion (particularly by cattle) is another cause of natural air pollution, leading to the release of methane, another greenhouse gas. In some regions of the world, vegetation - such as black gum, poplar, oak, and willow trees - emits significant amounts of volatile organic compounds (VOCs) on warmer days. These react with primary anthropogenic pollutants - specifically nitrogen oxides, sulfur dioxide and carbon compounds - to produce low-lying seasonal hazes that are rich in ozone.Volcanic Activity: Volcanic eruptions are a major source of natural air pollution. When an eruption occurs, it produces tremendous amounts of sulfuric, chlorine, and ash products, which are released into the atmosphere and can be picked up by winds to be dispersed over large areas. Additionally, compounds like sulfur dioxide and volcanic ash have been known to have a natural cooling effect, due to their ability to reflect solar radiation.

Anthropogenic Causes:

But by far the greatest contributing to air pollution today are those that are a result of human impact - i.e. man-made causes. These are largely the result of human reliance on fossil fuels and heavy industry, but can also be due to the accumulation of waste, modern agriculture, and other man-made processes.Fossil-Fuel Emissions: The combustion of fossil fuels like coal, petroleum and other factory combustibles is a major cause of air pollution. These are generally used in power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices. Providing air conditioning and other services also requires significant amounts of electricity, which in turn leads to more emissions.According to the Union of Concerned Scientists, industry accounts for 21% of greenhouse gas emissions in the US, while electricity generation accounted for another 31%. Meanwhile, emissions caused by gasoline-burning vehicles - i.e. CO, CO², nitrogen oxides, particulates and water vapor  - are also a significant source of air pollution.A study conducted by the UCS in 2013 showed that transportation accounted for more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into the air in the US. Globally, the situation is similar, with minor variations according to sector. According to the IPCC Fifth Assessment Report (2014), industry accounted for 21% of total greenhouse gas emissions, electricity and heat production for another 25%, and transportation accounted for 14%.Agriculture and Animal Husbandry: Greenhouse gas emissions from agriculture (aka. the cultivation of crops and livestock) is created by a combination of factors, one is the production of methane by cattle. Another cause is deforestation, where the need for pastureland and growing fields requires the removal of trees that would otherwise sequester carbon and clean the air.According to the IPCC Fifth Assessment Report, agriculture accounts for 24% of annual emissions. However, this estimate does not include the CO2 that ecosystems remove from the atmosphere by sequestering carbon in biomass, dead organic matter and soils, which offset approximately 20% of emissions from this sector.Waste: Landfills are also known to generate methane, which is not only a major greenhouse gas, but also an asphyxiant and highly flammable and potentially hazardous if a landfills grow unchecked. Population growth and urbanization have a proportional relationship with the production of waste, which in turn leads to greater demand for dumping grounds that are far removed from urban environments. These locations thus became a significant source of methane production.https://upload.wikimedia.org/wikipedia/commons/transcoded/c/ca/Human_Fingerprint_on_Global_Air_Quality.webm/Human_Fingerprint_on_Global_Air_Quality.webm.480p.webmFor some time, environmental scientists have been aware that the Earth has several self-regulating mechanisms. When it comes to the Earth's atmosphere, these mechanisms allow for the sequestration of carbon and other pollutants, ensuring that the balance of its ecosystem remains unaffected. Unfortunately, the growing impact humanity has had on the planet is threatening to permanently alter that balance.Basically, we are adding pollutants to the air (as well as the oceans and land masses) faster than the Earth's natural mechanisms can remove them. Ad the results of this are being felt in terms of acid rain, smog, global warming, and a number of health problems that can be directly attributed to exposure to these harmful pollutants. If we intend to go on living on planet Earth, then sustainability and less pollution need to be our goals!We have written many articles about air pollution for Universe Today. Here's Air Pollution Linked To Growth Of Life In Oceans, Could Nitrogen Pollution Give Tropical Flora a Much Needed Boost?, and How Does Carbon Capture Work?For more information, check out Visible Earth Homepage. And here's a link to NASA's Earth Observatory.Astronomy Cast also has episodes about planet Earth and humanity's impact on the environment - Episode 51: Earth, and Episode 308: Climate Change.

The post What Causes Air Pollution? appeared first on Universe Today.

Posted by Nelio Inacio at 9:05 AM 0 comments

Hawking Supports Tiny Spacecraft To Alpha Centauri

Hawking Supports Tiny Spacecraft To Alpha Centauri:



Artist’s impression of the planet around Alpha Centauri B. Credit: ESO


We know that Earth will die.Even if we beat global warming, and survive long enough to face and survive the next ice age, Earth will still die. Even if we build a peaceful civilization, protect the planet from asteroids, fight off mutant plagues and whatever else comes our way, life on Earth will die. No matter what we do, the Sun will reach the end of its life, and render Earth uninhabitable.So reaching for the stars is imperative. What sounds unrealistic to a great many people is a matter of practicality for people knowledgeable about space. To survive, we must have more than Earth.A project launched by billionaire Yuri Milner, and backed by Mark Zuckerberg, intends to send tiny spacecraft to our nearest stellar neighbour, the Alpha Centauri system. With an expert group assembled to gauge the feasibility, and with the support of eminent cosmologist Stephen Hawking, this idea is gaining traction.The distance to the Centauri system is enormous: 4.3 light years, or 1.34 parsecs. The project plans to use lasers to propel the craft, which should mean the travel time would be approximately 30 years, rather than the 30,000 year travel time that current technology restricts us to.[embed]https://www.youtube.com/watch?v=U2zCo6MCcCA[/embed]Of course, there are still many technological hurdles to overcome. The laser propulsion system itself is still only a nascent idea. But theoretically it's pretty sound, and if it can be mastered, should be able to propel space vehicles at close to relativistic speeds.There are other challenges, of course. The tiny craft will need robust solar sails as part of the propulsion system. And any instruments and cameras would have to be miniaturized, as would any communication equipment to send data back to Earth. But in case you haven't been paying attention, humans have a pretty good track record of miniaturizing electronics.Though the craft proposed are tiny, no larger than a microchip, getting them to the Alpha Centauri system is a huge step. Who knows what we'll learn? But if we're ever to explore another solar system, it has to start somewhere. And since astronomers think it's possible that the Centauri system could have potentially habitable planets, it's a great place to start.

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Posted by Nelio Inacio at 9:05 AM 0 comments

NASA Discovers 72 New Asteroids Near Earth

NASA Discovers 72 New Asteroids Near Earth:



Artist's impression of a Near-Earth Asteroid passing by Earth. Credit: ESA


Of the more than 600,000 known asteroids in our Solar System, almost 10 000 are known as Near-Earth Objects (NEOs). These are asteroids or comets whose orbits bring them close to Earth's, and which could potentially collide with us at some point in the future. As such, monitoring these objects is a vital part of NASA's ongoing efforts in space. One such mission is NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE), which has been active since December 2013.And now, after two years of study, the information gathered by the mission is being released to the public. This included, most recently, NEOWISE's second year of survey data, which accounted for 72 previously unknown objects that orbit near to our planet. Of these, eight were classified as potentially hazardous asteroids (PHAs), based on their size and how closely their orbits approach Earth.Originally launched back in 2009 as the Wide-field Survey Explorer (WISE), the spacecraft relied on its infrared telescope to look for previously undetected star clusters and main belt asteroids. In February of 2011, the mission ended and the spacecraft was put into hibernation. As of December 2013, it was reactivated for the purpose of surveying Near-Earth Objects (i.e. comets and asteroids) for the remainder of its service life.This mission not only involves scanning for NEOs at infrared wavelengths, but also characterizing previously known asteroids and comets to provide information about their sizes and compositions. James Bauer, the mission's deputy principal investigator, explained NEOWISE's operations to Universe Today via email:

"NEOWISE detects asteroids and comets, both near to Earth and further away, in the asteroid Main Belt for example, using infrared light. Because we look in the thermal infrared, the part of the spectrum where these small solar-system bodies are re-emitting the light they absorbed at other wavelengths, we can detect some of the darkest ones more easily than ground-based observatories, which look at their reflected light from the Sun. We can also get a better idea of the sizes, based on how much infrared light they re-emit. This way we detect and characterize Near Earth Objects that we may want to visit in the near future, and find new ones that may present impact risks as well as opportunities for exploration. NEOWISE has detected over 500 NEOs to date, including more than 81 discovered."
Paired with ground-based telescopes that examine space in visible-light wavelengths, the data it has provided has told us much in the past two years about asteroids within our Solar System. Since beginning its "second life", the NEOWISE mission has taken millions of images of the sky and measured more than 19,000 asteroids and comets.In addition to characterizing thousands of asteroids and identifying several new ones, the surveys revealed some interesting facts about NEOs that will make monitoring them easier, and help us mount missions to one someday. As Dr. Amy Mainzer, the principal investigator of the NEOWISE mission at NASA's Jet Propulsion Laboratory, told Universe Today via email:

"NEOWISE results indicate that about a third of the NEOs are extremely dark, which affects how we plan future surveys. With our IR measurements, we can determine NEO sizes, which helps us figure out how much energy a potential impactor would have. Objects that make close approaches to Earth offer both opportunity and risk: asteroids that make close approaches are more likely to be easier to get to from Earth. By finding close approaching NEOs, we can also find the most accessible destinations for future exploration."
Of the 19,000 asteroids studied, the mission team was able to identify 439 of them as NEOs, and further determined that eight of them can be classified as potentially hazardous asteroids (PHAs). But before anyone gets to worrying that these objects might collide with us someday, it would be good to keep some statistics in mind.For starters, since NASA and other space agencies began searching the Solar System for asteroids that have orbits that bring them close to Earth, some 14,166 NEOs have been discovered. What's more, the vast majority (over 13,000) have only been discovered since the year 2000, and over half since 2010. Of these, roughly half (7077) measure 140 meters in diameter.Sounds scary, doesn't it? But not so much when you consider that of these, only 879 are large enough to ever pose a serious threat to Earth (i.e. measuring 1 km or more in diameter). And whereas small objects (i.e. those averaging 4 meters or 13 feet in diameter) strike Earth about once a year, asteroids measuring 1 km or more in diameter have been known to hit Earth at an average of only twice every one million years.Of course, incidents like the Chelyabinsk meteorite (which measured 20 meters in diameter) remind us that even small NEOs that break up in the atmosphere can have a damaging effect - which in this case included 1,491 reported injuries and $33 million USD in property damage. However, the vast majority of the injuries caused by the airburst explosion were due to a lack of prior warning. Had the population been warned in advance, it is likely that most (if not all) of the injuries could have been prevented.Knowing precisely where NEOs (and PHAs) are with respect to Earth, their sizes, and what paths their orbits will take, are all crucial to making sure that, in the unlikely event that any of them hit Earth, that they don't cause harm. And thanks to NEOWISE, we've now got tabs on eight more of them. And until such time as we can create some kind of orbital defense platform to shoot incoming PHAs (I'm thinking guided missiles and laser guns!) knowing is all of the battle!And be sure to check out the new NASA movie below, which beautifully visualizes the data collected by NEOWISE so far:https://youtu.be/omnznsZThHAFurther Reading: NASA

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Posted by Nelio Inacio at 9:05 AM 0 comments

Are there Storms on the Moon?

Are there Storms on the Moon?:

Here on Earth, we’re always concerned with the weather.

“OK Google, am I going to need an umbrella tomorrow?”

[Google] No, rain is not expected tomorrow in Curtney. The forecast is 20 degrees and partly cloudy.

Uh, it’s pronounced “Courtenay”.

Fine, what if I lived on the Moon? OK Google, am I going to need an umbrella tomorrow on the Moon?

[Google] …

Let’s take Google’s silence for uncertainty.

The names of geological features on the Moon sure evoke mental images of weather. There’s the Ocean of Storms, also known as Oceanus Procellarum, or the Ocean of Clouds – aka Mare Nubium. In fact, most of the regions of the Moon are named after oceans. That’s got to count for something, right?

Many of the features on the moon are named as oceans. Credit: NASA
Many of the features of the moon were thought to be oceans. Credit: NASA
They got these names because the early astronomers thought they were seeing actual oceans on the Moon. They imagined vast seas, where heroic 6-legged creepy bug people plied the icy waves seeking fame, fortune and lunar plunder. I don’t know, like gold cheese or something. Seriously, they were making a lot of this stuff up until telescopes were invented.

But when the NASA astronauts finally set foot on the Moon, they knew they wouldn’t need to pack their snorkeling gear because there weren’t any oceans on the Moon, or really any atmosphere. The Moon is almost as dead and lifeless as space itself.

The storms we see battering the astronauts on every Mars science fiction story just can’t happen on the Moon because there’s no air there.

There’s an ongoing lethal radiation solar wind blowing from the Sun and deep space, but nothing that you’d be able to windsurf too.

So why isn’t there an atmosphere on the Moon? It all comes down to gravity. The Moon has about 1% of the mass of the Earth, which means that it doesn’t have enough gravity to hold onto any gas atmosphere. Anything that it did have would have been blown away by the solar wind billions of years ago.

We did a whole episode on what it would take to terraform the Moon, and it turns out you’d need to constantly replenish the atmosphere.

In fact, this is one of the reasons why the Martian atmosphere is so thin. It was probably thicker in the past, but the solar winds stripped off all the lighter atmosphere long ago. Now it’s just 1% the thickness of the Earth’s atmosphere.

Now, I’ve said that the Moon has almost no atmosphere. But almost no means partly yes. There is in fact an incredibly thin atmosphere surrounding the Moon which measures about a hundred trillionth the thickness of the Earth’s atmosphere.

There are a few sources of this atmosphere. First there’s volcanic outgassing that comes from the Moon. this contributes a little helium and radon. Then there’s the constant micrometeorite bombardment that kicks up pulverized lunar regolith.

Lunar sunrise sketches drawn by Commander E. A. Cernan during the Apollo 17 mission. Credit: NASA

Lunar sunrise sketches drawn by Commander E. A. Cernan during the Apollo 17 mission. Credit: NASA
But perhaps the strangest atmospheric feature is a storm that does rage across the surface of the Moon right at the terminator, the exact line between the Moon’s day side and its night side. It turns out the day side of the Moon is positively charged, and the night side is negatively charged.

As the terminator moves, the polarity of the dust flips and it drives it sideways. In fact, the astronauts who walked on the Moon actually reported seeing this. They saw bands or twilight rays in the sky around lunar sunrise/sunset.

Without a thick atmosphere, the surface of the Moon just doesn’t have any appreciable weather and definitely doesn’t have storms like we have on Earth. Mark Watney will need some other reason than weather to be stuck behind on the Moon.

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Posted by Nelio Inacio at 9:04 AM 0 comments

2016 Eta Aquarid Meteor Shower Peaks May 5-6

2016 Eta Aquarid Meteor Shower Peaks May 5-6:



A bright Eta Aquarid earthgrazer streaks across the northern lights in May 2013. Credit: Bob King


Itching to watch a meteor shower and don't mind getting up at an early hour? Good because this should be a great year for the annual Eta Aquarid (AY-tuh ah-QWAR-ids) shower which peaks on Thursday and Friday mornings May 5-6. While the shower is best viewed from tropical and southern latitudes, where a single observer might see between 25-40 meteors an hour, northern views won't be too shabby. Expect to see between 10-15 per hour in the hours before dawn.



Most showers trace their parentage to a particular comet. The Perseids of August originate from dust strewn along the orbit of comet 109P/Swift-Tuttle, which drops by the inner solar system every 133 years after “wintering” for decades just beyond the orbit of Pluto.







The upcoming Eta Aquarids  have the best known and arguably most famous parent of all: Halley’s Comet. Twice each year, Earth’s orbital path intersects dust and minute rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus.



Our first pass through Halley’s remains happens this week, the second in late October during the Orionid meteor shower. Like bugs hitting a windshield, the grains meet their demise when they smash into the atmosphere at 147,000 mph (237,000 km/hr) and fire up for a brief moment as meteors. Most comet grains are only crumb-sized and don't have a chance of reaching the ground as meteorites. To date, not a single meteorite has ever been positively associated with a particular shower.







The farther south you live, the higher the shower radiant will appear in the sky and the more meteors you’ll spot.  A low radiant means less sky where meteors might be seen. But it also means visits from "earthgrazers". These are meteors that skim or graze the atmosphere at a shallow angle and take many seconds to cross the sky. Several years back, I saw a couple Eta Aquarid earthgrazers during a very active shower. One other plus this year — no moon to trouble the view, making for ideal conditions especially if you can observe from a dark sky.



From mid-northern latitudes the radiant or point in the sky from which the meteors will appear to originate is low in the southeast before dawn. At latitude 50° north the viewing window lasts about 1 1/2 hours before the light of dawn encroaches; at 40° north, it’s a little more than 2 hours. If you live in the southern U.S. you’ll have nearly 3 hours of viewing time with the radiant 35° high.







Grab a reclining chair, face east and kick back for an hour or so between 3 and 4:30 a.m. An added bonus this spring season will be hearing the first birdsong as the sky brightens toward the end of your viewing session. And don't forget the sights above: a spectacular Milky Way arching across the southern sky and the planets of Mars and Saturn paired up in the southwestern sky.



Meteor shower members can appear in any part of the sky, but if you trace their paths in reverse, they’ll all point back to the radiant. Other random meteors you might see are called sporadics and not related to the Eta Aquarids. Meteor showers take on the name of the constellation from which they originate.



Aquarius is home to at least two showers. This one’s called the Eta Aquarids because it emanates from near the star Eta Aquarii. An unrelated shower, the Delta Aquarids, is active in July and early August. Don't sweat it if weather doesn't cooperate the next couple mornings. The shower will be active throughout the weekend, too.



Happy viewing and clear skies!

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Posted by Nelio Inacio at 9:03 AM 0 comments

A Mercury Transit Sequence

A Mercury Transit Sequence:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 May 4



See Explanation. Clicking on the picture will download the highest resolution version available.


A Mercury Transit Sequence

Image Credit & Copyright: Dominique Dierick


Explanation: This coming Monday, Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2006. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun. The above time-lapse sequence, superimposed on a single frame, was taken from a balcony in Belgium shows the entire transit of 2003 May 7. The solar crossing lasted over five hours, so that the above 23 images were taken roughly 15 minutes apart. The north pole of the Sun, the Earth's orbit, and Mercury's orbit, although all different, all occur in directions slightly above the left of the image. Near the center and on the far right, sunspots are visible. After Monday, the next transit of Mercury will occur in 2019.

NASA Coverage: 2016 May 9 Mercury Transit of the Sun

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Posted by Nelio Inacio at 9:02 AM 0 comments

Wednesday, May 4, 2016

Is A New Particle About To Be Announced?

Is A New Particle About To Be Announced?:



Data from two experiments at the LHC have independently hinted at the existence of a new type of particle. Image: CMS/LHC/CERN


Particle physicists are an inquisitive bunch. Their goal is a working, complete model of the particles and forces that make up the Universe, and they pursue that goal with a vigour matched by few other professions.



The Standard Model of Physics is the result of their efforts, and for 25 years or so, it has guided our thinking and understanding of particle physics. The best tool we have for studying physics further is the Large Hadron Collider (LHC), near Geneva, Switzerland. And some recent, intriguing results from the LHC points to the existence of a newly discovered particle.







The LHC has four separate detectors. Two of them are "general purpose" detectors, called ATLAS and CMS. Last year, separate experiments in both the ATLAS and CMS detectors produced what is best called a "bump" in their data. Initially, the two teams conducting the experiments were puzzled by the data. But when they compared them, they found that the bumps in their data were the same in both experiments, and they hinted at what could be a new type of particle, never before detected.



The two experiments involved smashing protons into each other at near-relativistic speeds. The collisions produced more high-energy photons than theory predicts. Not a lot more, but physics is a detailed endeavour, so even a slight increase in the amount of photons produced is a big deal. In physics, everything happens for a reason.



To be more specific, ATLAS and CMS recorded increased activity at an energy level around 750 giga electron-volts (GeV). What that means, for all you non-particle physicists, is that the new particle decays into two photons at the point of the proton-proton collision. If the new particle exists, that is.



A new particle would be a huge discovery. The Standard Model has describe all the particles present in nature pretty well. It even predicted the existence of one type of particle, the Higgs Boson, long before the LHC actually verified its existence. The discovery of a new type of particle would be very exciting news indeed, and could break the Standard Model.



Since this data from the experiments at the LHC was released last year, the physics world has been buzzing. Over 100 papers have been written to try to explain what the results might mean. But some caution is required.



The first thing scientists do when faced with results like this is to try to quantify the likelihood that it could be chance. If only one experiment had this bump in its data, then the likelihood that it was just a chance occurrence is pretty high. There are many reasons why an experiment can have a result like this, which is why repeatability is such a big deal in science. But when two independent, separate, experiments have the same result, people's ears perk up.



A few months have passed since the experiments were run, and in that time, the experimenters have tried to determine exactly what the likelihood is of these result occurring by chance. After working with the data, a funny thing has happened. The significance of the extra photons detected by CMS has risen, while the significance of the extra photons detected by ATLAS has fallen. This has definitely left physicists scratching their heads.



Also in that time, about four main explanations for the experimental results have percolated to the surface. One states that the new particle, if it exists, is made up of smaller particles, similar to how a proton is made up of quarks. These smaller particles could be held together by an unknown force. Some theoretical physicists think this is the best fit with the data.



Another possibility is that the new particle is a heavier version of the Higgs Boson. About 12 times heavier. Or it could be that the Higgs Boson itself is made up of smaller particles, and that's what the experiment detected.







Or, it could be the much-hypothesized graviton, the theoretical particle that carries the gravitational force. The four fundamental forces in the Universe are electromagnetism, the strong nuclear force, the weak nuclear force, and gravity. So far, we have discovered the particles that transmit all of those forces, except for gravity. If their was a new particle detected, and if it proved to be the graviton, that would be enormous, earth-shattering news. At least for those who are passionate about understanding nature.



That's a lot of "ifs" though.



There are a lot of holes in our knowledge of the Universe, and physicists are eager to fill those gaps. The discovery of a new particle might very well answer some basic questions about dark matter, dark energy, or even gravity itself. But there's a lot more experimentation to be done before the existence of a new particle can be announced.





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Posted by Nelio Inacio at 4:36 PM 0 comments

Aurora over Sweden

Aurora over Sweden:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2016 May 3



See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available.
Explanation: It was bright and green and stretched across the sky. This striking aurora display was captured last month just outside of Östersund, Sweden. Six photographic fields were merged to create the featured panorama spanning almost 180 degrees. Particularly striking aspects of this aurora include its sweeping arc-like shape and its stark definition. Lake Storsjön is seen in the foreground, while several familiar constellations and the star Polaris are visible through the aurora, far in the background. Coincidently, the aurora appears to avoid the Moon visible on the lower left. The aurora appeared a day after a large hole opened in the Sun's corona allowing particularly energetic particles to flow out into the Solar System. The green color of the aurora is caused by oxygen atoms recombining with ambient electrons high in the Earth's atmosphere.

Posted by Nelio Inacio at 4:34 PM 0 comments

Monday, May 2, 2016

A Super-Fast Star System Shrugs Its Shoulders At Physics

A Super-Fast Star System Shrugs Its Shoulders At Physics:



This annotated artist's conception illustrates our current understanding of the structure of the Milky Way galaxy. Image Credit: NASA


Astronomers have found a pair of stellar oddballs out in the edges of our galaxy. The stars in question are a binary pair, and the two companions are moving much faster than anything should be in that part of the galaxy. The discovery was reported in a paper on April 11, 2016, in the Astrophysical Journal Letters.The binary system is called PB3877, and at 18,000 light years away from us, it's not exactly in our neighborhood. It's out past the Scutum-Centaurus Arm, past the Perseus Arm, and even the Outer Arm, in an area called the galactic halo. This binary star also has the high metallicity of younger stars, rather than the low metallicity of the older stars that populate the outer reaches. So PB3877 is a puzzle, that's for sure.PB3877 is what's called a Hyper-Velocity Star (HVS), or rogue star, and though astronomers have found other HVS's, more than 20 of them in fact, this is the first binary one found. The pair consists of a hot sub-dwarf primary star that's over five times hotter than the Sun, and a cooler companion star that's about 1,000 degrees cooler than the Sun.Hyper-Velocity stars are fast, and can reach speeds of up to 1,198 km. per second, (2.7 million miles per hour,) maybe faster. At that speed, they could cross the distance from the Earth to the Moon in about 5 minutes. But what's puzzling about this binary star is not just its speed, and its binary nature, but its location.Hyper-Velocity stars themselves are rare, but PB3877 is even more rare for its location. Typically, hyper velocity stars need to be near enough to the massive black hole at the center of a galaxy to reach their incredible speeds. A star can be drawn toward the black hole, accelerated by the unrelenting pull of the hole, then sling-shotted on its way out of the galaxy. This is the same action that spacecraft can use when they gain a gravity assist by travelling close to a planet.This video shows how stars can accelerate when their orbit takes them close to the super-massive black holes at the center of the Milky Way.[embed]https://www.youtube.com/watch?v=duoHtJpo4GY[/embed]But the trajectory of PB3877 shows astronomers that it could not have originated near the center of the galaxy. And if it had been ejected by a close encounter with the black hole, how could it have survived with its binary nature intact? Surely the massive pull of the black hole would have destroyed the binary relationship between the two stars in PB3877. Something else has accelerated it to such a high speed, and astronomers want to know what, exactly, did that, and how it kept its binary nature.Barring a close encounter with the super-massive black hole at the center of the Milky Way, there are a couple other ways that PB3877 could have been accelerated to such a high velocity.One such way is a stellar interaction or collision. If two stars were travelling at the right vectors, a collision between them could impart energy to one of them and propel it to hyper-velocity. Think of two pool balls on a pool table.Another possibility is a supernova explosion. It's possible for one of the stars in a binary pair to go supernova, and eject it's companion at hyper-velocity speeds. But in these cases, either stellar collision or supernova, things would have to work out just right. And neither possibility explains how a wide-binary system like this could stay intact.Fraser Cain sheds more light on Hyper-Velocity Stars, or Rogue Stars, in this video.[embed]https://www.youtube.com/watch?v=JCj_EsoM6eM[/embed]There is another possibility, and it involves Dark Matter. Dark Matter seems to lurk on the edge of any discussion around something unexplained, and this is a case in point. The researchers think that there could be a massive cocoon or halo of Dark Matter around the binary pair, which is keeping their binary relationship intact.As for where the binary star PB3788 came from, as they say in the conclusion of their paper, "We conclude that the binary either formed in the halo or was accreted from the tidal debris of a dwarf galaxy by the Milky Way." And though the source of this star's formation is an intriguing question, and researchers plan follow up study to verify the supernova ejection possibility, its possible relationship with Dark Matter is also intriguing.

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Icy Hot: Europa’s Frozen Crust Could Be Warmer Than We Thought

Icy Hot: Europa’s Frozen Crust Could Be Warmer Than We Thought:



Europa's cracked, icy surface imaged by NASA's Galileo spacecraft in 1998. Credit: NASA/JPL-Caltech/SETI Institute.


All the worlds may be ours except Europa but that only makes the ice-covered moon of Jupiter all the more intriguing. Beneath Europa's thin crust of ice lies a tantalizing global ocean of liquid water somewhere in the neighborhood of 100 kilometers deep—which adds up to more liquid water than is on the entire surface of the Earth. Liquid water plus a heat source(s) to keep it liquid plus the organic compounds necessary for life and...well, you know where the thought process naturally goes from there.And now it turns out Europa may have even more of a heat source than we thought. Yes, a big component of Europa's water-liquefying warmth comes from tidal stresses enacted by the massive gravity of Jupiter as well as from the other large Galilean moons. But exactly how much heat is created within the moon's icy crust as it flexes has so far only been loosely estimated. Now, researchers from Brown University in Providence, RI and Columbia University in New York City have modeled how friction creates heat within ice under stress, and the results were surprising.Although 3,100-km-wide Europa is coated in ice and technically has the smoothest surface in the Solar System, it's far from featureless. Its frozen crust features enormous regions of broken "chaos terrain"  and is covered in long, crisscrossing fractures filled with reddish-brown material (which may be a form of sea salt), as well as crumpled, mountain-like ridges that appear curiously fresh.These ridges are thought to be a result of a form of tectonics, except not with plates of rock like on Earth but rather shifting slabs of frozen water. But where the energy needed to drive that process is coming from—and what happens to all the frictional heat created during it—isn't well known."People have been using simple mechanical models to describe the ice," said geophysicist Christine McCarthy, Lamont Assistant Research Professor at Columbia University who led the research while a graduate student at Brown University. "They weren't getting the kinds of heat fluxes that would create these tectonics. So we ran some experiments to try to understand this process better."By mechanically subjecting ice samples to various forms of pressure and stress, similar to the conditions that would be found on Europa as it orbits Jupiter, the researchers found that most of the heat is generated within deformities in the ice, rather than between the individual grains as was previously thought. This difference means there's likely a lot more heat moving through Europa's ice layers, which would affect both its behavior and its thickness."Those physics are first order in understanding the thickness of Europa's shell," said Reid Cooper, Earth science professor and McCarthy's research partner at Brown. "In turn, the thickness of the shell relative to the bulk chemistry of the moon is important in understanding the chemistry of that ocean. And if you're looking for life, then the chemistry of the ocean is a big deal."When it comes to Europa's icy crust there have traditionally been two camps of thought: the thin-icers and the thick-icers. Thin-icers estimate the moon's crust to be at most only a few kilometers thick—possibly coming very close to the surface in places, if not breaking through entirely—while those in the thick-ice camp think it could be tens of times thicker. While there are data to support both hypotheses, it remains to be seen which these new findings will best support.Luckily we won't have to wait terribly long to find out how thick the moon's icy crust really is. A recently-approved NASA mission will launch to Europa in the 2020s to explore its surface, interior composition, and potential habitability. The mission may (i.e., should) also include a lander, although of what fashion has yet to be determined. But when the data from that mission do finally come in, many of our long-standing questions about this mystifying icy world will finally be answered.The team's research is published in the June 1 issue of Earth and Planetary Science Letters.Source: PhysOrg.com 

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Is Alpha Centauri The Best Place To Look For Aliens?

Is Alpha Centauri The Best Place To Look For Aliens?:



Project Starshot, an initiative sponsored by the Breakthrough Foundation, is intended to be humanity's first interstellar voyage. Credit: breakthroughinitiatives.org


For generations, human beings have fantasized about the possibility of finding extra-terrestrial life. And with our ongoing research efforts to discover new and exciting extrasolar planets (aka. exoplanets) in distant star systems, the possibility of actually visiting one of these worlds has received a real shot in the arm. Unfortunately, given the astronomical distances involved, not to mention the cost of mounting an expedition, doing so presents numerous significant challenges.However, Russian billionaire Yuri Milner and the Breakthrough Foundation - an international organization committed to exploration and scientific research -  is determined to mount an interstellar mission to Alpha Centauri, our closest stellar neighbor, in the coming years. With the backing of such big name sponsors as Mark Zuckerberg and Stephen Hawking, his latest initiative (named "Project Starshot") aims to send a tiny spacecraft to the Alpha Centauri system to search for planets and signs of life.Consisting of an ultra-light nanocraft and a lightsail, the concept calls for a ground-based laser array to push the lightsail up to speeds of hundreds of kilometers a second, towing the nanocraft into deep space. Such a system would allow the tiny spacecraft to conduct a flyby mission to Alpha Centauri in about 20 years after it is launched, which could then beam home images of possible planets, as well as other scientific data such as analysis of magnetic fields.In essence, Starshot seeks to leverage recent technological developments to mount an interstellar mission that will reach another star within a single generation. As we explained in another article ("How Long Would It Take To Travel To The Nearest Star?"), using existing technology, it would take between 19,000 to 81,000 years for a spacecraft to make the trip to even the nearest star, depending on whether chemical rockets or ion engines were used.Hence, the Foundation's advisory board explored all potential methods for creating a craft that could travel at relativistic speeds - up to 20% the speed of light - so it could traverse the 4.37 light year distance in just 20 years. They determined that a tiny craft, roughly the size of a refrigerator magnet and weighing in the vicinity of a few grams, would be the best model for a spacecraft. They further determined that the best propulsion method would be laser-driven lightsail, which is not hampered by the limits of conventional methods.With a massive ground-based laser directing the sail, the plan is to accelerate the nanocraft to its terminal velocity before it reaches a distance of about one million km from Earth (which is the limit to which the laser beam can be focused on the meter-scale sail). All told, the nanocraft will experience an acceleration of about 60,000 g (sixty-thousands times the force of Earth's gravity, which works out to just under 600,000 m/s²).As Professor Avi Loeb, the Frank B. Baird, Jr. Professor of Science at Harvard University and chairman of the Foundation's Advisory Board, explained to Universe Today via email:

"{O]nly one offers a path forward: using beamed (laser) light to push a sail attached to a lightweight (gram-scale) smart payload (with a camera, transmitter and thrusters). This approach benefits from two major technological advances that were realized recently: miniaturization of electronics (developed by the cell phone industry) and the construction arrays of lasers that combine to make a very powerful and focused beam of light (developed by the defense industry). Interstellar travel is challenging, but based on these technological advances, we believe that there is a path forward without obvious show stoppers. The project is ambitious but doable."
In addition to accomplishing the dream of countless generations (i.e. traveling to another star system), Breakthrough Starshot hopes to generate important supplementary benefits to astronomy in the meantime. Much like the Apollo Program of the 1960s, the Breakthrough Starshot program hopes to stimulate the development of technologies that will be beneficial here on Earth.These include demonstrating proof-of-concept technology that will enable the exploration the solar system, the detection and study of Near Earth Objects (NEOs), and the benefits to material science that solar sail development will bring. The development of laser arrays will also have major implications for the science of optical systems, and the laser communication devices used on Starshot will likely lead to better communication with airplanes and satellites around Earth.As Pete Worden, the Executive Director Project Breakthrough StarShot, told Universe Today via email:

"The project goals are to develop and demonstrate the technologies, particularly with respect to high power laser beaming technology and gram-class lightsail-craft that could enable humanity to send these craft to the nearest star system, Alpha Centauri within a generation.  We hope to mobilize the world’s expertise to make this possible.  The program will be an open international program.  Yuri Milner has provided our initial funding.  Renowned physicist Stephen Hawking and Facebook founder Mark Zuckerberg have joined Yuri Milner as the governing board of the project."
Based on the Foundation's best estimates, this project could achieve its goal of dispatching their interstellar traveler within a few decades time. And with a 20 some-odd year transit time, we could be gaining vital information about the nearest star system (including whether or not it has life-supporting exoplanets) by the 2050s or 2060s.Naturally, there are still several engineering hurdles that would need to be overcome before Starshot can become a reality. For example, propelling a gram-scale spacecraft to 20% the speed of light will require a laser beam of that could generate about 100 Gigawatts of power over the course of a few minutes. The Project intends to build this laser array on the ground, simply because that would be much cheaper than building one in space.This, in turn, creates the challenge of optical-blurring due to atmospheric turbulence. Using adaptive optics (measuring atmospheric effects and correcting for them) is believed to be able to compensate for that. Such a method has been tested on the scale of the largest telescopes (10 meters in diameter), but would need to be tested on a scale of 1 km before it can be considered feasible.What's more, there are plenty of doubts as to the missions intended target, not to mention the likelihood that the mission will succeed. For instance, while Alpha Centauri may be the nearest star, thus making it the natural choice for interstellar exploration, there is little reason to suspect we will find any exoplanets there.Years back, astronomers announced the detection of a possible planet circling Alpha Centauri B with an orbital period of 3.24 days - which was named Alpha Cen Bb. However, subsequent examinations revealed that the detection of this exoplanet was the result of the window function (time sampling) of the original data. If we hope to find exoplanets, then we might need to look further afield - like Epsilon Eridani, a mere 10.5 light years away (which would result in a travel time of 55 years for the proposed nanocraft).And, as Paul Gilster of Centauri Dreams points out, the concept presents numerous challenges that will require technical advances not currently in existence. For example, beyond the issue of laser power and adaptive optics, there are issues with the sail concept itself that are likely to prove difficult. Essentially, this comes down to the need for a balance to be struck between powerful lasers and a sail that is capable of withstanding them:

"Moreover, we have to design a sail that will ‘ride’ the beam rather than be blown off it, and one that will be so highly reflective that it will absorb less than 1/100,000th of the energy applied to it. These are problems that Robert Forward faced with his Starwisp design, a kilometer-wide ‘spider web’ of a sail driven by microwaves, with sensors scattered throughout the sail itself. It was Geoffrey Landis who would go on to show that as described, Starwisp would likely vaporize under the powerful beam meant to drive it to Alpha Centauri, causing a flurry of re-thinking of sail materials and design. But leaving the fuel at home is a powerful technique, and advances in technology may get us to the kind of materials that can withstand the photon torrent."
Addressing the design called for by Breakthrough Starshot - a thin, round disc that is about the size of a picnic table in diameter, and which would have its entire electronics suite in the center - Gilster sees additional problems. "We’ve also got a problem in that concept,"  he says, "because Jim Benford has pointed out that a flat sail is not a good ‘beam-rider’ - we’ll likely have to look at the kind of curved sail designs both Jim and brother Gregory Benford have studied in lab work at the Jet Propulsion Laboratory."In the end, the only reason to send a probe to Alpha Centauri is because of its proximity. And mounting the mission will require that the Breakthrough Foundation and its supporters come up with new and innovative solutions to the hurdles they face. But given that the opportunities for research and exploration will still be abundant, the reasonable timelines involved, and the likelihood of success, the mission certainly appears to be doable.Previous efforts by the Breakthrough Foundation's include Breakthrough Listen, the largest scientist research program aimed at detecting transmissions from distant stars. These include monitoring for radio transmissions and optical laser transmissions using advanced instruments that are significantly more sensitive than anything currently in use, combined with advanced software and data analysis. The program will span 10 years and cost an estimated $100 million, surveying the 1,000,000 closest stars to Earth and the 100 closest galaxies to the Milky Way.There's also Breakthrough Message, a $1 million competition aimed at encouraging a global debate about the ethics and possible methods of communicating with possible intelligent beings beyond Earth. The competition is open, and the prize will be awarded to anyone who is able to design a message (in digital format) that best represents Earth and humanity to other civilizations.And be sure to enjoy this video from the Breakthrough Foundation that illustrates the mission concept:https://youtu.be/RoCm6vZDDiQFurther Reading: Breakthrough Initiatives

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Posted by Nelio Inacio at 3:39 PM 0 comments

Dwarf Dark Matter Galaxy Hides In Einstein Ring

Dwarf Dark Matter Galaxy Hides In Einstein Ring:



The large blue light is a lensing galaxy in the foreground, called SDP81, and the red arcs are the distorted image of a more distant galaxy. By analyzing small distortions in the red, distant galaxy, astronomers have determined that a dwarf dark galaxy, represented by the white dot in the lower left, is companion to SDP81. The image is a composite from ALMA and the Hubble. Image: Y. Hezaveh, Stanford Univ./ALMA (NRAO/ESO/NAOJ)/NASA/ESA Hubble Space Telescope


Everybody knows that galaxies are enormous collections of stars. A single galaxy can contain hundreds of billions of them. But there is a type of galaxy that has no stars. That's right: zero stars.These galaxies are called Dark Galaxies, or Dark Matter Galaxies. And rather than consisting of stars, they consist mostly of Dark Matter. Theory predicts that there should be many of these Dwarf Dark Galaxies in the halo around 'regular' galaxies, but finding them has been difficult.Now, in a new paper to be published in the Astrophysical Journal, Yashar Hezaveh at Stanford University in California, and his team of colleagues, announce the discovery of one such object. The team used enhanced capabilities of the Atacamas Large Millimeter Array to examine an Einstein ring, so named because Einstein's Theory of General Relativity predicted the phenomenon long before one was observed.An Einstein Ring is when the massive gravity of a close object distorts the light from a much more distant object. They operate much like the lens in a telescope, or even a pair of eye-glasses. The mass of the glass in the lens directs incoming light in such a way that distant objects are enlarged.Einstein Rings and gravitational lensing allow astronomers to study extremely distant objects, by looking at them through a lens of gravity. But they also allow astronomers to learn more about the galaxy that is acting as the lens, which is what happened in this case.If a glass lens had tiny water spots on it, those spots would add a tiny amount of distortion to the image. That's what happened in this case, except rather than microscopic water drops on a lens, the distortions were caused by tiny Dwarf Galaxies consisting of Dark Matter. “We can find these invisible objects in the same way that you can see rain droplets on a window. You know they are there because they distort the image of the background objects,” explained Hezaveh. The difference is that water distorts light by refraction, whereas matter distorts light by gravity.As the ALMA facility increased its resolution, astronomers studied different astronomical objects to test its capabilities. One of these objects was SDP81, the gravitational lens in the above image. As they examined the more distant galaxy being lensed by SDP81, they discovered smaller distortions in the ring of the distant galaxy. Hezaveh and his team conclude that these distortions signal the presence of a Dwarf Dark Galaxy.[embed]https://vimeo.com/158971342[/embed]But why does this all matter? Because there is a problem in the Universe, or at least in our understanding of it; a problem of missing mass.Our understanding of the formation of the structure of the Universe is pretty solid, at least in the larger scale. Predictions based on this model agree with observations of the Cosmic Microwave Background (CMB) and galaxy clustering. But our understanding breaks down somewhat when it comes to the smaller scale structure of the Universe.One example of our lack of understanding in this area is what's known as the Missing Satellite Problem. Theory predicts that there should be a large population of what are called sub-halo objects in the halo of dark matter surrounding galaxies. These objects can range from things as large as the Magellanic Clouds down to much smaller objects. In observations of the Local Group, there is a pronounced deficit of these objects, to the tune of a factor of 10, when compared to theoretical predictions.Because we haven't found them, one of two things needs to happen: either we get better at finding them, or we modify our theory. But it seems a little too soon to modify our theories of the structure of the Universe because we haven't found something that, by its very nature, is hard to find. That's why this announcement is so important.The observation and identification of one of these Dwarf Dark Galaxies should open the door to more. Once more are found, we can start to build a model of their population and distribution. So if in the future more of these Dwarf Dark Galaxies are found, it will gradually confirm our over-arching understanding of the formation and structure of the Universe. And it'll mean we're on the right track when it comes to understanding Dark Matter's role in the Universe. If we can't find them, and the one bound to the halo of SDP81 turns out to be an anomaly, then it's back to the drawing board, theoretically.It took a lot of horsepower to detect the Dwarf Dark Galaxy bound to SDP81. Einstein Rings like SDP81 have to have enormous mass in order to exert a gravitational lensing effect, while Dwarf Dark Galaxies are tiny in comparison. It's a classic 'needle in a haystack' problem, and Hezaveh and his team needed massive computing power to analyze the data from ALMA.ALMA, and the methodology developed by Hezaveh and team will hopefully shed more light on Dwarf Dark Galaxies in the future. The team thinks that ALMA has great potential to discover more of these halo objects, which should in turn improve our understanding of the structure of the Universe. As they say in the conclusion of their paper, "... ALMA observations have the potential to significantly advance our understanding of the abundance of dark matter substructure."

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Posted by Nelio Inacio at 3:38 PM 0 comments

Antarctica Provides Plenty Of Mars Samples Right Now

Antarctica Provides Plenty Of Mars Samples Right Now:



Mars! Martian meteorites make their way to Earth after being ejected from Mars by a meteor impact on the Red Planet. Image: NASA/National Space Science Data Center.


Sometimes, the best way to study Mars is to stay home. There's no substitute for actual missions to Mars, but pieces of Mars have made the journey to Earth, and saved us the trip. Case in point: the treasure trove of Martian meteorites that NASA is gathering from Antarctica.NASA scientists aren't the first ones to find meteorites in the Earth's polar regions. As early as the 9th century, people in the northern polar regions made use of iron from meteorites for tools and hunting weapons. The meteorite iron was traded from group to group over long distances. But for NASA, the hunt for meteorites is focused on Antarctica.In Antarctica, the frigid temperatures preserve meteorites for a long time, which makes them valuable artifacts in the quest to understand Mars. Meteorites tend to accumulate in places where creeping glacial ice moves them to. When the ice meets a rock obstacle, the meteorites are deposited there, making them easier to find. Recently arrived meteorites are also easily spotted on the surface of the Antarctica ice.[embed]https://www.youtube.com/watch?v=60w3WbVwhh8[/embed]The US began collecting meteorites in Antarctica in 1976, and to date more than 21,000 meteorites and meteorite fragments have been found. In fact, more of them are found in Antarctica than in the rest of the world combined. These meteorites are then shared with scientists around the world.Collecting meteorites in Antarctica is not a walk in the park. It's physically gruelling and hazardous work. Antarctica is not an easy environment to live and work in, and just surviving there takes planning and teamwork. But the scientific payoff is huge, which keeps NASA going back.Meteorites from the Moon and other bodies also arrive on Earth, and are collected in Antarctica. They can tell scientists important things about the evolution and formation of the Solar System, the origin of organic chemical compounds necessary for life, and the origin of the planets themselves.

How Do Martian Meteorites Get To Earth?

A few things have to go right for a Martian meteorite to make it to Earth. First, a meteorite has to collide with Mars. That meteorite has to be big enough, and hit the surface of Mars with enough force, that rock from Mars is propelled off the surface with enough speed to escape Mars' gravity.[embed]https://www.youtube.com/watch?v=oZNSszq9O-g[/embed]After that, the meteor has to travel through space and avoid a thousand other fates, like being drawn to one of the other planets, or the Sun, by the gravitational pull of those bodies. Or being flung off into the far reaches of empty space, lost forever. Then, if it manages to make it to Earth, and be pulled in by Earthly gravity, it must be large enough to survive entry into Earth's atmosphere.

The Science

Part of the scientific value in meteorites lies not in their source, but in the time that they were formed. Some meteorites have travelled through space for so long, they're like time travellers. These ancient meteorites can tell scientists a lot about conditions in the early Solar System.Meteorites from Mars tell scientists a few things. Since they've survived re-entry into Earth's atmosphere, they can tell engineers about the dynamics of such a journey, and help inform spacecraft design. Since they contain chemical signatures and elements unique to Mars, they can also tell mission specialists things about surviving on Mars.They can also provide clues to one of the greatest mysteries in space exploration: Did life exist on Mars? A Martian meteorite found in the Sahara desert in 2011 contained ten times the amount of water as other Martian meteorites, and added evidence to the idea that Mars was once a wet world, suitable for life.NASA's program to hunt for meteorites in Antarctica has been going strong for many years, and there's really no reason to stop doing it, since this is the only way to get Martian samples into a laboratory. Each one they find is like a puzzle piece, and like a jigsaw puzzle, you never know which one will complete the big picture.

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Posted by Nelio Inacio at 3:33 PM 0 comments

April Lunacy: Getting Ready for the Full ‘Mini-Moon’

April Lunacy: Getting Ready for the Full ‘Mini-Moon’:



2015 Mini-Moon


Do you welcome the extra evening light of the Full Moon, or curse the additional light pollution? Either way, this week's Full Moon on Friday April 22nd is special. It's the smallest Full Moon of 2016, something we here at Universe Today have christened the Mini-Moon.Mini-Moon 2016: This year's Mini-Moon falls on April 22nd at 5:25 Universal Time (UT), just 13 hours and 19 minutes after lunar apogee the evening prior at 16:06 UT on April 21st. Though apogee on the 21st is 406,350 km distant – a bit on the far end, but the third most distant for the year by 300 km — this week's Full Moon is the closest to apogee for 2016 time-wise. The 2015 Mini-Moon was even closer, in the 10 hour range, but you'll have to wait until December 10th, 2030 to find a closer occurance.What is the Mini-Moon, you might ask? As with the often poorly defined Supermoon, we like to eschew the ambiguous '90% of its orbit' definition, and simply refer to it as a Full Moon occurring within 24 hours of lunar apogee, or its farthest point from the Earth in its orbit.Fun fact: the 29.55 day period from perigee to perigee (or lunar apogee-to-apogee) is known as an anomalistic month.Thank our Moon's wacky orbit for all this lunacy. Inclined 5.14 degrees relative to the ecliptic plane, the Moon returns to the same phase (say, Full back to Full) every 29.53 days, known as a synodic month. The Moon can appear 33.5' across during perigee, and shrink to 29.4' across near apogee.And don't fear the 'Green Moon,' and rumors going 'round ye' ole internet that promise a jaded Moon will occur in April or May; this is 100% non-reality based, seeking to join the legends of Super, Blood, and Full Moons, Black and Blue.The April Full Moon is also known as the Full Pink Moon to the Algonquin Indians. The April Full Moon, can, on occasion be the Full Moon ushering in Easter (known as the Paschal Moon) as per the rule established by the 325 AD council of Nicaea, stating Easter falls on the first Sunday after the first Full Moon after the fixed date of the Vernal Equinox of March 21st. Easter can therefore fall as late as April 25th, as next occurs on 2038. The future calculation of Easter by the Church gets the Latin supervillain-sounding name of Computus.Of course, the astronomical vernal equinox doesn't always fall on March 21st, and to complicate matters even further, the Eastern Orthodox Church uses the older Julian Calendar and therefore, Easter doesn't always align with the modern western Gregorian calendar used by the Roman Catholic Church.The Moon can create further complications in modern timekeeping as well.Here's one wonderful example we recently learned of in our current travels. The Islamic calendar is exclusively based on the synodic cycle of the Moon, and loses 11 days a year in relation to the Gregorian solar calendar. Now, Morocco officially adopted Daylight Saving (or Summer) Time in 2007, opting to make the spring forward during the last weekend of March, as does the European Union to the north. However, the country reverts back to standard time during the month of Ramadan... otherwise, the break in the daily fast during summer months would fall towards local midnight.You can see a curious future situation developing. In 2016, Ramadan runs from sundown June 5th, to July 4th. Each cycle begins with the sighting of the thin waxing crescent Moon. However, as Ramadan falls earlier, you'll get a bizarre scenario such as 2022, when Morocco springs forward on March 27th, only to fall back to standard time six days later on April 2nd on the start of Ramadan, only to jump forward again one lunation later on April 30th!Morocco is the only country we've come across in our travels that follows such a convoluted convention of timekeeping.Fun fact #2: the next 'Mini-Moon' featuring a lunar eclipse occurs on July 27th 2018.And the Spring Mini-Moon sets us up for Supermoon season six months later this coming October-November-December. Though lunar perigees less than 24 hours from Full usually occur as a trio, an apogee less than 24 hours from Full is nearly always a solitary affair, owing to the slightly slower motion of the Moon at a farther distance.Don't miss the shrunken Mini-Moon rising on the evenings of Thursday April 21st and Friday 22nd, coming to a sky near you.

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Posted by Nelio Inacio at 3:32 PM 0 comments
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