Tag: northern hemisphere (page 1 of 2)

October Swirls by Meline Portia Lafont October 3, 2016

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High-Energy Cosmic Neutrinos Observed At The Geographic South Pole

An team of international experts has announced a new observation of high-energy neutrino particles using an instrument funded by the National Science Foundation (NSF). The particles from beyond our galaxy have been detected at the geographic South Pole, using a massive instrument buried deep in ice.The scientists from the IceCube Collaboration, a research team with headquarters at the Wisconsin IceCube Particle Astrophysics Center at the University of Wisconsin-Madison, pub [...]

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NASA Releases New Pictures of Ceres

Bright spots on Ceres continue to puzzle astronomersExcerpt from sciencetimes.com NASA has released the most brilliant images of Ceres to date, truly showcasing the surface of the dwarf planet located in the asteroid belt.  The new images could...

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MAVEN mission finds early surprises in Martian atmosphere

Excerpt from chroniclebulletin.com University of Colorado-led Mars mission has observed two unexpected phenomena in the Martian atmosphere, unveiled Wednesday at the 46th Lunar and Planetary Science Conference in Texas.NASA describes the finds by MA...

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Powerful solar storm sparks stunning aurora around the world ~ Images of the Northern Lights 2015

Excerpt from cnn.com  A severe solar storm created a stunning display of light in the night sky over parts of the United States, Europe, Australia and New Zealand early Wednesday morning, spotted by those lucky enough to be awake in the wee h...

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A Complete Guide to the March 20th Total Solar Eclipse

Totality! The 2012 total solar eclipse as seen from Australia. Credit and copyright: www.hughca.com.

Excerpt from universetoday.com

The first of two eclipse seasons for the year is upon us this month, and kicks off with the only total solar eclipse for 2015 on Friday, March 20th.

And what a bizarre eclipse it is. Not only does this eclipse begin just 15 hours prior to the March equinox marking the beginning of astronomical spring in the northern hemisphere, but the shadow of totality also beats path through the high Arctic and ends over the North Pole.

An animation of the March 20th eclipse. Credit: NASA/GSFC/AT Sinclair.

Already, umbraphiles — those who chase eclipses — are converging on the two small tracts of terra firma where the umbra of the Moon makes landfall: the Faroe and Svalbard islands. All of Europe, the northern swath of the African continent, north-central Asia and the Middle East will see a partial solar eclipse, and the eclipse will be deeper percentage-wise the farther north you are .
2015 features four eclipses in all: two total lunars and two solars, with one total solar and one partial solar eclipse. Four is the minimum number of eclipses that can occur in a calendar year, and although North America misses out on the solar eclipse action this time ’round, most of the continent gets a front row seat to the two final total lunar eclipses of the ongoing tetrad on April 4th and September 28th.

How rare is a total solar eclipse on the vernal equinox? Well, the last total solar eclipse on the March equinox occurred back in 1662 on March 20th. There was also a hybrid eclipse — an eclipse which was annular along a portion of the track, and total along another — on March 20th, 1681. But you won’t have to wait that long for the next, as another eclipse falls on the northward equinox on March 20th, 2034.

The path of the March 20th eclipse across Europe, including start times for the partial phases, and the path of totality, click to enlarge. For more maps showing the percentage of occlusion, elevation, and more, click here. Credit: Michael Zeiler/GreatAmercianEclipse.com.

Note that in the 21st century, the March equinox falls on March 20th, and will start occasionally falling on March 19th in 2044. We’re also in that wacky time of year where North America has shifted back to ye ‘ole Daylight Saving (or Summer) Time, while Europe makes the change after the eclipse on March 29th. It really can wreak havoc with those cross-time zone plans, we know…
The March 20th eclipse also occurs only a day after lunar perigee, which falls on March 19th at 19:39 UT. This is also one of the closer lunar perigees for 2015 at 357,583 kilometres distant, though the maximum duration of totality for this eclipse is only 2 minutes and 47 seconds just northeast of the Faroe Islands.

Views from selected locales in Europe and Africa. Credit: Stellarium.

This eclipse is number 61 of 71 in solar saros series 120, which runs from 933 to 2754 AD. It’s also the second to last total in the series, with the final total solar eclipse for the saros cycle occurring one saros later on March 30th, 2033.

What would it look like to sit at the North Pole and watch a total solar eclipse on the first day of Spring? It would be a remarkable sight, as the disk of the Sun skims just above the horizon for the first time since the September 2014 equinox. Does this eclipse occur at sunrise or sunset as seen from the pole? It would be a rare spectacle indeed!

An equinoctal eclipse as simulated from the North Pole. Credit: Stellarium.

Practicing eclipse safety in Africa. Credit: Michael Zeiler/GreatAmericanEclipse.com

Safety is paramount when observing the Sun and a solar eclipse. Eye protection is mandatory during all partial phases across Europe, northern Asia, North Africa and the Middle East. A proper solar filter mask constructed of Baader safety film is easy to construct, and should fit snugly over the front aperture of a telescope. No. 14 welder’s goggles are also dense enough to look at the Sun, as are safety glasses specifically designed for eclipse viewing. Observing the Sun via projection or by using a pinhole projector is safe and easy to do.

A solar filtered scope ready to go in Tucson, Arizona. Credit: photo by author.

Weather is always the big variable in the days leading up to any eclipse. Unfortunately, March in the North Atlantic typically hosts stormy skies, and the low elevation of the eclipse in the sky may hamper observations as well. From the Faroe Islands, the Sun sits 18 degrees above the horizon during totality, while from the Svalbard Islands it’s even lower at 12 degrees in elevation. Much of Svalbard is also mountainous, making for sunless pockets of terrain that will be masked in shadow on eclipse day. Mean cloud amounts for both locales run in the 70% range, and the Eclipser website hosts a great in-depth climatology discussion for this and every eclipse.

The view of totality and the planets as seen from the Faroe Islands. Credit: Starry Night.

But don’t despair: you only need a clear view of the Sun to witness an eclipse!

Solar activity is also another big variable. Witnesses to the October 23rd, 2014 partial solar eclipse over the U.S. southwest will recall that we had a massive and very photogenic sunspot turned Earthward at the time. The Sun has been remarkably calm as of late, though active sunspot region 2297 is developing nicely. It will have rotated to the solar limb come eclipse day, and we should have a good grasp on what solar activity during the eclipse will look like come early next week.

And speaking of which: could an auroral display be in the cards for those brief few minutes of totality? It’s not out of the question, assuming the Sun cooperates.  Of course, the pearly white corona of the Sun still gives off a considerable amount of light during totality, equal to about half the brightness of a Full Moon. Still, witnessing two of nature’s grandest spectacles — a total solar eclipse and the aurora borealis — simultaneously would be an unforgettable sight, and to our knowledge, has never been documented!

We also put together some simulations of the eclipse as seen from Earth and space:

Note that an area of southern Spain may witness a transit of the International Space Station during the partial phase of the eclipse. This projection is tentative, as the orbit of the ISS evolves over time. Be sure to check CALSky for accurate predictions in the days leading up to the eclipse.

The ISS transits the Sun during the eclipse around 9:05 UT as seen from southern Spain. Credit: Starry Night.

Can’t make it to the eclipse? Live in the wrong hemisphere? There are already a few planned webcasts for the March 20th eclipse:

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Ancient ‘Blue’ Mars Lost an Entire Ocean to Space

Artist impression of Mars ocean

Excerpt from news.discovery.com

Mars was once a small, wet and blue world, but over the past 4 billion years, Mars dried up and became the red dust bowl we know today.

But how much water did Mars possess? According to research published in the journal Science, the Martian northern hemisphere was likely covered in an ocean, covering a region of the approximate area as Earth’s Atlantic Ocean, plunging, in some places, to 1.6 kilometers (1 mile) deep.

“Our study provides a solid estimate of how much water Mars once had, by determining how much water was lost to space,” said Geronimo Villanueva, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the new paper, in an ESO news release. “With this work, we can better understand the history of water on Mars.”

Over a 6-year period, Villanueva and his team used the ESO’s Very Large Telescope (in Chile) and instruments at the W. M. Keck Observatory and the NASA Infrared Telescope Facility (both on Mauna Kea in Hawaii) to study the distribution of water molecules in the Martian atmosphere. By building a comprehensive map of water distribution and seasonal changes, they were able to arrive at this startling conclusion.

It is becoming clear that, over the aeons, Mars lost the majority of its atmosphere to space. That also goes for its water. Though large quantities of water were likely frozen below the surface as the atmosphere thinned and cooled, the water contained in an ocean of this size must have gone elsewhere — it must have also been lost to space.

This artist’s impression shows how Mars may have looked about four billion years ago. The young planet Mars would have had enough water to cover its entire surface in a liquid layer about 140 meters deep, but it is more likely that the liquid would have pooled to form an ocean occupying almost half of Mars’s northern hemisphere. 
The water in Earth’s oceans contains molecules of H2O, the familiar oxygen atom bound with 2 hydrogen atoms, and, in smaller quantities, the not-so-familiar HDO molecule. HDO is a type of water molecule that contains 1 hydrogen atom, 1 oxygen atom and 1 deuterium atom. The deuterium atom is an isotope of hydrogen; whereas hydrogen consists of 1 proton and an electron, deuterium consists of 1 proton, 1 neutron and 1 electron. Therefore, due to the extra neutron the deuterium contains, HDO molecules are slightly heavier than the regular H2O molecules.

Also known as “semi-heavy water,” HDO is less susceptible to being evaporated away and being lost to space, so logic dictates that if water is boiled (or sublimated) away on Mars, the H2O molecules will be preferentially lost to space whereas a higher proportion of HDO will be left behind.

By using powerful ground-based observatories, the researchers were able to determine the distribution of HDO molecules and the H2O molecules and compare their ratios to liquid water that is found in its natural state.

Of particular interest is Mars’ north and south poles where icecaps containing water and carbon dioxide ice persist to modern times. The water those icecaps contain is thought to document the evolution of water since the red planet’s wet Noachian period (approximately 3.7 billion years ago) to today. It turns out that the water measured in these polar regions is enriched with HDO by a factor of 7 when compared with water in Earth’s oceans. This, according to the study, indicates that Mars has lost a volume of water 6.5 times larger than the water currently contained within the modern-day icecaps.

Therefore, the volume of Mars’ early ocean must have been at least 20 million cubic kilometers, writes the news release.

Taking into account the Martian global terrain, most of the water would have been concentrated around the northern plains, a region dominated by low-lying land. An ancient ocean, with this estimate volume of water, would have covered 19 percent of the Martian globe, a significant area considering the Atlantic Ocean covers 17 percent of the Earth’s surface.

“With Mars losing that much water, the planet was very likely wet for a longer period of time than previously thought, suggesting the planet might have been habitable for longer,” said Michael Mumma, also of NASA’s Goddard Space Flight Center.

This estimate is likely on the low-side as Mars is thought to contain significant quantities of water ice below its surface — a fact that surveys such as this can be useful for pinpointing exactly where the remaining water may be hiding.

Ulli Kaeufl, of the European Southern Observatory and co-author of the paper, added: “I am again overwhelmed by how much power there is in remote sensing on other planets using astronomical telescopes: we found an ancient ocean more than 100 million kilometers away!”
Source: ESO

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Mars Had an Ocean, Scientists Say, Pointing to a Treasure Trove of New Data

Excerpt from nytimes.com

After six years of planetary observations, scientists at NASA say they have found convincing new evidence that ancient Mars had an ocean.

It was probably the size of the Arctic Ocean, larger than previously estimated, the researchers reported on Thursday. The body of water spread across the low-lying plain of the planet’s northern hemisphere for millions of years, they said.

If confirmed, the findings would add significantly to scientists’ understanding of the planet’s history and lend new weight to the view that ancient Mars had everything needed for life to emerge.
“The existence of a northern ocean has been debated for decades, but this is the first time we have such a strong collection of data from around the globe,” said Michael Mumma, principal investigator at NASA’s Goddard Center for Astrobiology and an author of the report, published in the journal Science. “Our results tell us there had to be a northern ocean.”
But other experts said the question was hardly resolved. The ocean remains “a hypothesis,” said Ashwin Vasavada, project scientist of the Curiosity rover mission at the Jet Propulsion Laboratory in Pasadena, Calif.

Dr. Mumma and Geronimo Villanueva, a planetary scientist at NASA, measured two slightly different forms of water in Mars’ atmosphere. One is the familiar H2O, which consists of two hydrogen atoms and one oxygen atom.

The other is a slightly “heavier” version of water, HDO, in which the nucleus of one hydrogen atom contains a neutron. The atom is called deuterium.

The two forms exist in predictable ratios on Earth, and both have been found in meteorites from Mars. A high level of heavier water today would indicate that there was once a lot more of the “lighter” water, somehow lost as the planet changed.

The scientists found eight times as much deuterium in the Martian atmosphere than is found in water on Earth. Dr. Villanueva said the findings “provide a solid estimate of how much water Mars once had by determining how much water was lost to space.”

He said the measurements pointed to an ancient Mars that had enough water to cover the planet to a depth of at least 137 meters, or about 450 feet. Except for assessments based on the size of the northern basin, this is the highest estimate of the amount of water on early Mars that scientists have ever made.

The water on Mars mostly would have pooled in the northern hemisphere, which lies one to three kilometers — 0.6 to 1.8 miles — below the bedrock surface of the south, the scientists said.
At one time, the researchers estimated, a northern ocean would have covered about 19 percent of the Martian surface. In comparison, the Atlantic Ocean covers about 17 percent of Earth’s surface.

The new findings come at a time when the possibility of a northern ocean on Mars has gained renewed attention.

The Curiosity rover measured lighter and heavier water molecules in the Gale Crater, and the data also indicated that Mars once had substantial amounts of water, although not as much as Dr. Mumma and Dr. Villanueva suggest.

“The more water was present — and especially if it was a large body of water that lasted for a longer period of time — the better the chances are for life to emerge and to be sustained,” said Paul Mahaffy, chief of the atmospheric experiments laboratory at the Goddard Space Flight Center.

Just last month, the science team running the Curiosity rover held its first formal discussion about the possibility of such an ocean and what it would have meant for the rest of Mars.

Scientists generally agree that lakes must have existed for millions of years in Gale Crater and elsewhere. But it is not clear how they were sustained and replenished.

“For open lakes to remain relatively stable for millions of years — it’s hard to figure how to do that without an ocean,” Dr. Vasavada said. “Unless there was a large body of water supplying humidity to the planet, the water in an open lake would quickly evaporate and be carried to the polar caps or frozen out.”

Yet climate modelers have had difficulty understanding how Mars could have been warm enough in its early days to keep water from freezing. Greenhouse gases could have made the planet much warmer at some point, but byproducts of those gases have yet to be found on the surface.

James Head, a professor of geological sciences at Brown University, said in an email that the new paper had “profound implications for the total volume of water” on ancient Mars.

But, he added, “climate models have great difficulty in reconstructing an early Mars with temperatures high enough to permit surface melting and liquid water.”

Also missing are clear signs of the topographic and geological features associated with large bodies of water on Earth, such as sea cliffs and shorelines.

Based on low-resolution images sent back by the Viking landers, the geologist Timothy Parker and his colleagues at the NASA Jet Propulsion Lab reported in 1989 the discovery of ancient shorelines. But later high-resolution images undermined their conclusions.

Still, Dr. Parker and his colleagues have kept looking for — and finding, they say — some visible signs of a northern ocean. The new data “certainly encourages me to do more,” he said in an interview.

Other researchers have also been looking for signs of an ancient ocean.

In 2013, Roman DiBiase, then a postdoctoral student at the California Institute of Technology, and Michael Lamb, an assistant professor of geology there, identified what might have been a system of channels on Mars that originated in the southern hemisphere and emptied steeply into the northern basin — perhaps, they said, water flowing through a delta to an ocean.

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As Dawn spacecraft closes in on Ceres, things start to look ‘rough’

Ceres: Dawn spies dwarf planet
This image, taken 147,000 miles from Ceres by NASA's Dawn spacecraft, is part of a series of views representing the best look so far at the dwarf planet. The spacecraft is set to enter orbit March 6. (NASA)

Eat your heart out, Hubble! NASA’s Dawn spacecraft is in the home stretch of its journey to Ceres and has snapped the best images yet of the dwarf planet. Grainy as they are, the new views of the 590-mile-wide world are already turning up unexpected features on the surface.
“What we expect at Ceres is to be surprised, so it’s getting off to a good start,” said deputy principal investigator Carol Raymond.
The images, taken 147,000 miles from Ceres on Jan. 25, are 30% higher-resolution than the images taken by NASA’s Hubble Space Telescope in 2003 and 2004. They measure 43 pixels wide, a significant improvement over Dawn’s images from earlier this month, which were 27 pixels across.
The images show significant brightness and darkness variations over the surface – particularly a bright spot gleaming in the northern hemisphere and darker spots in the southern hemisphere. While the scientists were aware of those major spots, they weren’t expecting to see quite so much texture on the surface, said Raymond, a geophysicist at the Jet Propulsion Laboratory.

Ceres is fairly warm by ice-world standards; temperatures generally range from 180 to 240 Kelvin (or minus-136 degrees Fahrenheit to minus-28 degrees Fahrenheit), Raymond said. Theoretically, the ice on Ceres’ surface should start to flow as it warms up, smoothing out any bumps such as those from impact craters. But the brightness variations across the surface make it appear very rough, she said.
“This is just starting to illuminate the fact that Ceres is one of these unique bodies that has astrobiological potential ... and it’s just continued to become more intriguing as we’ve been marching inexorably closer,” she added.

Ceres was not the first stop in Dawn’s 3-billion-mile journey. The first was the protoplanet Vesta, which is vastly different from its fellow mega-asteroid, Ceres. Where Vesta is dry and lumpy, Ceres is icy and round, massive enough to have been pulled into a planet-like shape. Scientists want to find out why these two space-fossils from the early solar system ended up with such different geophysical life stories.
At least with Vesta, there were meteorites linked to the asteroid that planetary scientists can study, Raymond pointed out. For Ceres, there are no such space rocks found on Earth – so the researchers have somewhat less of an idea of what to expect.

“I am excited,” Raymond said. “Just having had the wild ride at Vesta, I’m also just in awe of what’s going to happen. It’s going to be amazing.”

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First Weekend of the New Year Brings Quadrantid Meteor Shower

Excerpt from savingadvice.com

For those who want to save money, one of the best free resources available to everyone are nature’s displays. The first weekend of the New Year will begin with a bang, although this bang will be of interstellar origins. This weekend (Jan. 3), the first meteor display of 2015 will reach its peak on Saturday night in a display of lights known as the Quadrantid meteor shower. According to science reporter Geoff Gaherty, “Meteor shows are usually named after the constellation in the sky where their radiant is located: the point in the sky from which they appear to radiate. Thus, the Perseids [showers] are named for Perseus and the Geminids [showers] are named for Gemini.”

Interestingly, Gaherty informs the reader that “there is no constellation named Quadrans” whence scientists derived the name Quadrantid. Instead, there was once the Quadrans Muralis constellation, which became a part of the constellation Bootes in 1922. The name of the meteor, however, was retained.

Quadrantids are also known to be a January meteor shower, as opposed to the more famous Perseids observed in August or the Geminids seen in December. Additionally, quadrantid meteors are less frequently observed than the other two meteor showers given that its peak intensity lasts only hours. Still, Gaherty writes that the Quadrantid shower “can produce as many bright meteors during its peak as the more famous Perseids.” Thus, in order to view this spectacular display, “timing is everything.”

Using past observations, researchers predict that the peak of 2015′s Quadrantid meteor shower will occur at 9 p.m. EST on Jan. 3. “During this time, the radiant will be close to the northern horizon and there is a good chance of seeing…meteors coming in close to the horizon to the east and west.”

The radiant, however, is expected to rise higher in the northeastern sky, until more meteors become visible in the east. According to Gaherty, the best time to then observe the Quadrantids will be between midnight and 2 a.m. (some reports say dawn) in the Northern Hemisphere.

Unfortunately, the shooting stars may be hard to view because of an almost-full moon on Saturday, which will radiate its own impressive brightness. Still, NASA predicts that at the peak of the Quadrantid shower, approximately 80 meteors an hour will be released, which should be remarkable in its own right.

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Ursid Meteor Shower Peaks: Here’s How to See It

Image: Geminid meteor shower
December is usually marked by a series of meteor showers. Geminid meteors (like the one seen in this picture of Florida) light up the skies at the beginning of the month, while the Ursids - which peak Monday night (Dec. 22) - put on a show just before Christmas.

Excerpt from space.com

The Ursid meteor shower peaks tonight, and it should be a great show. 

When skywatchers think of meteor showers during the month of December, the Geminid shower (which peaked earlier this month) usually comes to mind. But the Ursid meteor shower — peaking tonight and into the wee hours of Tuesday (Dec. 23) morning — should also offer skywatchers a good view this year. 

Even if you can't see tonight's meteor shower due to light pollution or bad weather, you can still catch the Ursids online thanks to the Slooh Community Observatory. Tune in for Slooh's Ursid meteor shower webcast tonight starting at 8 p.m. EST (0100 Dec. 23 GMT) live on Space.com. You can also watch the webcast directly through Slooh.
The Ursids are so named because they appear to fan out from the vicinity of the bright orange star Kochab, in the constellation of Ursa Minor, the Little Bear. Kochab is the brighter of the two outer stars in the bowl of the Little Dipper (the other being Pherkad), that seem to march in a circle like sentries around the North Star, Polaris. These meteors are sometimes called the Umids, in a rather unsuccessful attempt to make clear that their radiant is in Ursa Minor, not Ursa Major. 

The fact that Kochab is positioned so near to the north pole of the sky means that this star almost never sets for most viewers in the Northern Hemisphere. And since the Ursids seem to fan out from this particular region of the sky, you have a reference point to look for these faint, medium-speed meteors all through the night if you care to. 

The fact that the shower peaks tonight is good news for observers braving the cold to see the display. The moon is just one day past its new phase, meaning that light reflected from Earth's natural satellite won't wash out the shower.

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Top 10 Ridiculously Common Science Myths

There is nothing better than a bit of mythbusting (which accounts for the popularity of the television program of the same name), so here we are again, presenting you with a new list of terribly common misconceptions and myths – this time about science.

Evolutionary Improvements
Evolution Std.Jpg
The Myth: Evolution causes something to go from “lower” to “higher”
While it is a fact that natural selection weeds out unhealthy genes from the gene pool, there are many cases where an imperfect organism has survived. Some examples of this are fungi, sharks, crayfish, and mosses – these have all remained essentially the same over a great period of time. These organisms are all sufficiently adapted to their environment to survive without improvement.
Other taxa have changed a lot, but not necessarily for the better. Some creatures have had their environments changed and their adaptations may not be as well suited to their new situation. Fitness is linked to their environment, not to progress.

Humans Pop In Space
The Myth: When exposed to the vacuum of space, the human body pops
This myth is the result of science fiction movies which use it to add excitement or drama to the plot. In fact, a human can survive for 15 – 30 seconds in outer space as long as they breathe out before the exposure (this prevents the lungs from bursting and sending air into the bloodstream). After 15 or so seconds, the lack of oxygen causes unconsciousness which eventually leads to death by asphyxiation.
Brightest Star
800Px-Sirius A And B Artwork.Jpg
The Myth: Polaris is the brightest star in the northern hemisphere night sky
Sirius is actually brighter with a magnitude of ?1.47 compared to Polaris’ 1.97 (the lower the number the brighter the star). The importance of Polaris is that its position in the sky marks North – and for that reason it is also called the “North Star”. Polaris is the brightest star in the constellation Ursa Minor and, interestingly, is only the current North Star as pole stars change over time because stars exhibit a slow continuous drift with respect to the Earth’s axis.
Five Second Rule
The Myth: Food that drops on the floor is safe to eat if you pick it up within five seconds
This is utter bunkum which should be obvious to most readers. If there are germs on the floor and the food lands on them, they will immediately stick to the food. Having said that, eating germs and dirt is not always a bad thing as it helps us to develop a robust immune system. I prefer to have a “how-tasty-is-it” rule: if it is something really tasty, it can sit there for ten minutes for all I care – I will still eat it.
Dark side of the Moon
179077120 (1)
The Myth: There is a dark side of the moon
Actually – every part of the moon is illuminated at sometime by the sun. This misconception has come about because there is a side of the moon which is never visible to the earth. This is due to tidal locking; this is due to the fact that Earth’s gravitational pull on the moon is so immense that it can only show one face to us. Wikipedia puts it rather smartly thus: “Tidal locking occurs when the gravitational gradient makes one side of an astronomical body always face another; for example, one side of the Earth’s Moon always faces the Earth. A tidally locked body takes just as long to rotate around its own axis as it does to revolve around its partner. This synchronous rotation causes one hemisphere constantly to face the partner body.”

Brain Cells
Brain Cell.Jpg
The Myth: Brain cells can’t regenerate – if you kill a brain cell, it is never replaced
The reason for this myth being so common is that it was believed and taught by the science community for a very long time. But in 1998, scientists at the Sweden and the Salk Institute in La Jolla, California discovered that brain cells in mature humans can regenerate. It had previously been long believed that complex brains would be severely disrupted by new cell growth, but the study found that the memory and learning center of the brain can create new cells – giving hope for an eventual cure for illnesses like Alzheimer’s.
Pennies from Heaven
The Myth: A penny dropped from a very high building can kill a pedestrian below
This myth is so common it has even become a bit of a cliche in movies. The idea is that if you drop a penny from the top of a tall building (such as the Empire State Building) – it will pick up enough speed to kill a person if it lands on them on the ground. But the fact is, the aerodynamics of a penny are not sufficient to make it dangerous. What would happen in reality is that the person who gets hit would feel a sting – but they would certainly survive the impact.
Friction Heat
The Myth: Meteors are heated by friction when entering the atmosphere
When a meteoroid enters the atmosphere of the earth (becoming a meteor), it is actually the speed compressing the air in front of the object that causes it to heat up. It is the pressure on the air that generates a heat intense enough to make the rock so hot that is glows brilliantly for our viewing pleasure (if we are lucky enough to be looking in the sky at the right time). We should also dispel the myth about meteors being hot when they hit the earth – becoming meteorites. Meteorites are almost always cold when they hit – and in fact they are often found covered in frost. This is because they are so cold from their journey through space that the entry heat is not sufficient to do more than burn off the outer layers.
The Myth: Lightning never strikes the same place twice
Next time you see lightning strike and you consider running to the spot to protect yourself from the next bolt, remember this item! Lightning does strike the same place twice – in fact it is very common. Lightning obviously favors certain areas such as high trees or buildings. In a large field, the tallest object is likely to be struck multiple times until the lightning moves sufficiently far away to find a new target. The Empire State Building gets struck around 25 times a year.
Gravity in Space
Astronaut Banjo.Jpg
The Myth: There is no gravity in space
In fact, there is gravity in space – a lot of it. The reason that astronauts appear to be weightless because they are orbiting the earth. They are falling towards the earth but moving sufficiently sideways to miss it. So they are basically always falling but never landing. Gravity exists in virtually all areas of space. When a shuttle reaches orbit height (around 250 miles above the earth), gravity is reduced by only 10%.
Inspired by an excellent LiveScience Article. This article is licensed under the GFDL because it contains quotations from Wikipedia.

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Extreme Storms on Uranus Puzzle Astronomers

Infrared Uranus
These infrared images of the planet Uranus show a white spot that is actually a massive storm on the planet. This image was recorded by the Keck II telescope atop Mauna Kea in Hawaii on Aug. 6, 2014 in the 2.2-micron wavelength.

Excerpt from  space.com
By Elizabeth Howell

Uranus is finally having some summer storms, seven years after the planet reached its closest approach to the sun, leaving scientists wondering why the massive storms are so late.

The usually quiet gas giant now has such "incredibly active" weather that some of the features are even visible to amateurs, said Imke de Pater, the project's lead researcher and an astronomer at the University of California, Berkeley. Astronomers first announced the extreme storms on Uranus in August, and have been trying to understand them ever since.

This is by far the most active weather de Pater's team has seen on Uranus in the past decade, examining its storms and northern convective features. It also paints a different picture of the quiet planet Voyager 2 saw when the NASA spacecraft flew by in 1986.

An infrared composite image of the two hemispheres of Uranus obtained with Keck Telescope adaptive optics. The component colors of blue, green, and red were obtained from images made at near infrared wavelengths of 1.26, 1.62, and 2.1 microns respectively. The images were obtained on July 11 and 12, 2004. The North pole is at 4 o'clock. Lawrence Sromovsky, University of Wisconsin-Madison/W.W. Keck Observatory

"This type of activity would have been expected in 2007, when Uranus' once-every-42-year equinox occurred and the sun shined directly on the equator," research co-investigator Heidi Hammel, of the Association of Universities for Research in Astronomy, said in a statement. "But we predicted that such activity would have died down by now. Why we see these incredible storms now is beyond anybody's guess."

But here's where the mystery comes in: As far as anyone can tell, Uranus has no source of internal heat. Sunlight is thought to be responsible for changes in its atmosphere, such as storms. But the sun's light is currently weak in Uranus' northern hemisphere, so scientists are puzzled as to why that area is so active today.


Huge storms on Uranus

Based on the colors and structure of the storm spotted by amateurs, professional astronomers believe it could hint at a vortex deeper in the atmosphere — similar to phenomena spotted on Jupiter, such as the Great Red Spot.

Follow-up observations with the Keck II telescope revealed that the storm was still raging, although it had changed its shape, and possibly its intensity.

Also contributing to the effort was the Hubble Space Telescope, which examined the entire planet of Uranus Oct. 14 in several wavelengths. The observations revealed storms spanning several altitudes, over a distance of about 5,592 miles (9,000 kilometers).

"If, indeed, these features are high-altitude clouds generated by flow perturbations associated with a deeper vortex system, such drastic fluctuations in intensity would indeed be possible," said Larry Sromovsky, a planetary scientist at the University of Wisconsin-Madison who performed the newer work.

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