Tag: Hawaii (page 1 of 5)

Why Do We Still Vaccinate? – 25 Questions From A Former Vaccine Advocate

Brian Rogers, Prevent DiseaseI used to be pro vaccine. I know the feeling of thinking others were just plain crazy and wrong for not vaccinating their children and themselves. ‘Irresponsible!’ I said when pointing my finger. I’d use the same old arguments about polio and small pox and how vaccines saved us from all those horrible diseases and just swallowing and regurgitating the propaganda I was brought up with. It was only recently, in 2009 that I started question [...]

View Article Here   Read More

Rare Quartet of Quasars Found in the Early Universe

This image shows a rare view of four quasars, indicated by white arrows, found together by astronomers using the Keck Observatory in Hawaii. The bright galactic nuclei are embedded in a giant nebula of cool, dense gas visible in the image as a blue haze. Hennawi & Arrigoni-Battaia, MPIA

Excerpt from smithsonian.com

The odds of success would make a Vegas bookie sit up and take notice. But in a one-in-10 million chance, astronomers surveying the sky have found a group of four tightly packed quasars in one of the most distant parts of the universe. The rare grouping may be a nascent galaxy cluster, and its unusually cold cradle of gas could prompt a re-think of how we model the early universe.

Quasars are among the brightest objects known—according to NASA, each one gives off more energy than 100 mature galaxies combined. But quasars are found only in the far reaches of the universe and can't be seen with the naked eye. Because of the time it takes light to travel that far, detecting such distant objects is akin to seeing back in time, so astronomers think quasars are the seeds of young galaxies, powered by gases falling into the supermassive black holes at their cores. As matter falls inward and gets close to the speed of light, it emits radiation that we can pick up with telescopes.

The quasar phase doesn't last long, only about a thousandth of a galaxy's lifetime. After that, the brightness dies down as the inflow of matter slows, says study leader Joseph Hennawi, an astrophysicist at the Max Planck Institute in Germany. Seeing any two quasars close together while they are still bright is a chancy business, so his team wasn't sure what they'd find when they set out to survey quasars using the W.M. Keck Observatory in Hawaii. To their surprise, they quickly pinpointed four of them in close proximity, cosmically speaking. The quartet is huddled up in an area of sky less than 600,000 light-years across that sits about 10 billion light-years from Earth.

"The authors found it by investigating the environment of just 29 bright quasars," says Michele Trenti, a senior lecturer at the University of Melbourne's School of Physics. "So at face value it seems like winning the lottery with a handful of tickets."
That's not all that was strange about this quasar quartet. The foursome was found inside a cloud of cold, dark gas, and the team's observations suggest that similar clouds surround about 10 percent of the tens of thousands of known quasars. That's odd, because according to current theories, quasars in groups like this should be surrounded by hot plasma, or ionized gas, at a temperature of about 10 million degrees.

“What this means is that there is some physical process that the models aren’t capturing,” says Hennawi, whose team reports the discovery this week in Science.

View Article Here   Read More

Ascension Earth 2015-05-09 17:40:00

 MAY 9, 2015: USGS map shows the location of the 4.5 quake (large blue dot in Ka'u) among the many smaller quakes that occurred on the Big Island over the last two weeks.

MAY 9, 2015: USGS map shows the location of the 4.5 quake (large blue dot in Ka'u) among the many smaller quakes that occurred on the Big Island over the last two weeks. - See more at: http://www.bigislandvideonews.com/2015/05/09/4-5-earthquake-shakes-big-island/#sthash.SS9H2Oiy.dpuf


Magnitude-4.5 earthquake shakes Big Island of Hawaii; people around isle report light shakingNAʻALEHU – A magnitude-4.5 earthquake located in the Kaʻū District shook the Island of Hawaii on Saturday, May 9, at 2:18 a.m., HST.  The quake was centered 5 miles north of Naʻalehu at a depth of 6 miles, according to Wes Thelen, the Seismic Network Manager for the USGS Hawaiian Volcano Observatory. There were three aftershocks (magnitudes 1.6, 1.5, 1.4) of the earthquake were recorded as of 3:30 a.m., HST. Scientists say additional aftershocks are possible and could be felt.  Over 70 reports claimed to feel the earthquake within an hour of the event. Light shaking has been reported across the island. At these shaking intensities (Intensity IV), damage to buildings or structures is not expected, scientists said.      Over the past 30 years, the area north of Nāʻālehu has experienced 6 earthquakes, including today’s event, with magnitudes greater than 4.0 and at depths of 5–13 km (3.1–8.1 mi). This area of Kaʻū is a seismically active region where a magnitude-6.2 earthquake occurred in 1919. Areas adjacent to this morning’s event experienced earthquakes of magnitudes 6.0, 7.1, and 7.9 in 1868.      The depth, location, and recorded seismic waves of today’s earthquake suggest a source on the large fault plane between the old ocean floor and overlying volcanic crust, a common source for earthquakes in this area. USGS Hawaiian Volcano Observatory   The earthquake caused no detectable changes in Kīlauea Volcano’s ongoing eruptions, on Mauna Loa, or at other active volcanoes on the Island of Hawaiʻi, says USGS. A magnitude-3.1 earthquake that occurred in Kīlauea Caldera about one minute before the magnitude-4.5 earthquake was unrelated to the Naʻalehu event.  The Big Island has been experiencing elevated seismicity beneath Kīlauea’s summit and upper East and Southwest Rift Zones the past few weeks.
NAʻALEHU – A magnitude-4.5 earthquake located in the Kaʻū District shook the Island of Hawaii on Saturday, May 9, at 2:18 a.m., HST.
The quake was centered 5 miles north of Naʻalehu at a depth of 6 miles, according to Wes Thelen, the Seismic Network Manager for the USGS Hawaiian Volcano Observatory. There were three aftershocks (magnitudes 1.6, 1.5, 1.4) of the earthquake were recorded as of 3:30 a.m., HST. Scientists say additional aftershocks are possible and could be felt.
Over 70 reports claimed to feel the earthquake within an hour of the event. Light shaking has been reported across the island. At these shaking intensities (Intensity IV), damage to buildings or structures is not expected, scientists said.
Over the past 30 years, the area north of Nāʻālehu has experienced 6 earthquakes, including today’s event, with magnitudes greater than 4.0 and at depths of 5–13 km (3.1–8.1 mi). This area of Kaʻū is a seismically active region where a magnitude-6.2 earthquake occurred in 1919. Areas adjacent to this morning’s event experienced earthquakes of magnitudes 6.0, 7.1, and 7.9 in 1868.
The depth, location, and recorded seismic waves of today’s earthquake suggest a source on the large fault plane between the old ocean floor and overlying volcanic crust, a common source for earthquakes in this area. USGS Hawaiian Volcano Observatory
The earthquake caused no detectable changes in Kīlauea Volcano’s ongoing eruptions, on Mauna Loa, or at other active volcanoes on the Island of Hawaiʻi, says USGS. A magnitude-3.1 earthquake that occurred in Kīlauea Caldera about one minute before the magnitude-4.5 earthquake was unrelated to the Naʻalehu event.
The Big Island has been experiencing elevated seismicity beneath Kīlauea’s summit and upper East and Southwest Rift Zones the past few weeks.
- See more at: http://www.bigislandvideonews.com/2015/05/09/4-5-earthquake-shakes-big-island/#sthash.SS9H2Oiy.dpuf

View Article Here   Read More

See Saturn moon’s ‘soda ocean’ shooting to surface in sheets

 Excerpt from  cnet.comEnceladus may have a warm ocean beneath its icy surface, but it may also be shooting through that crust in big sheets, perhaps filled with sea monkeys.       We already know that Saturn's ...

View Article Here   Read More

Astronomers find baby blue galaxy close to dawn of time

Astronomers have discovered a baby blue galaxy that is the furthest away in distance and time - 13.1 billion years - that they’ve ever seen. Photo: Pascal Oesch and Ivelina Momcheva, NASA, European Space Agency via AP

Excerpt from smh.com.au

A team of astronomers peering deep into the heavens have discovered the earliest, most distant galaxy yet, just 670 million years after the Big Bang.

Astronomers have discovered a baby blue galaxy that is the furthest away in distance and time - 13.1 billion years - that they’ve ever seen.
Close-up of the blue galaxy

The findings, described in Astrophysical Journal Letters, reveal a surprisingly active, bright galaxy near the very dawn of the cosmos that could shed light on what the universe, now 13.8 billion years old, was really like in its young, formative years.

"We're actually looking back through 95 per cent of all time to see this galaxy," said study co-author Garth Illingworth, an astronomer at the University of California, Santa Cruz.

"It's really a galaxy in its infancy ... when the universe was in its infancy."

Capturing an image from a far-off light source is like looking back in time. When we look at the sun, we're seeing a snapshot of what it looked like eight minutes ago.

The same principle applies for the light coming from the galaxy known as EGS-zs8-1. We are seeing this distant galaxy as it existed roughly 13.1 billion years ago.

EGS-zs8-1 is so far away that the light coming from it is exceedingly faint. And yet, compared with other distant galaxies, it is surprisingly active and bright, forming stars at roughly 80 times the rate the Milky Way does today.

This precocious little galaxy has built up the mass equivalent to about 8 billion suns, more than 15 per cent of the mass of the Milky Way, even though it appears to have been in existence for a mere fraction of the Milky Way's more than 13 billion years.

"If it was a galaxy near the Milky Way [today], it would be this vivid blue colour, just because it's forming so many stars," Illingworth said.

One of the many challenges with looking for such faint galaxies is that it's hard to tell if they're bright and far, or dim and near. Astronomers can usually figure out which it is by measuring how much that distant starlight gets stretched, "redshifted", from higher-energy light such as ultraviolet down to optical and then infrared wavelengths. The universe is expanding faster and faster, so the further away a galaxy is, the faster it's going, and the more stretched, or "redder", those wavelengths of light will be.

The astronomers studied the faint light from this galaxy using NASA's Hubble and Spitzer space telescopes. But EGS-zs8-1 seemed to be too bright to be coming from the vast distances that the Hubble data suggested.

To narrow in, they used the MOSFIRE infrared spectrograph at the Keck I telescope in Hawaii to search for a particularly reliable fingerprint of hydrogen in the starlight known as the Lyman-alpha line. This fingerprint lies in the ultraviolet part of the light spectrum, but has been shifted to redder, longer wavelengths over the vast distance between the galaxy and Earth.

It's a dependable line on which to base redshift (and distance) estimates, Illingworth said - and with that settled, the team could put constraints on the star mass, star formation rate and formation epoch of this galaxy.

The telltale Lyman-alpha line also reveals the process through which the universe's haze of neutral hydrogen cleared up, a period called the epoch of reionisation. As stars formed and galaxies grew, their ultraviolet radiation eventually ionised the hydrogen and ended the "dark ages" of the cosmos.

Early galaxies-such as EGS-zs8-1 - are "probably the source of ultraviolet radiation that ionised the whole universe", Illingworth said.

Scientists have looked for the Lyman-alpha line in other distant galaxies and come up empty, which might mean that their light was still being blocked by a haze of neutral hydrogen that had not been ionised yet.

But it's hard to say with just isolated examples, Illingworth pointed out. If scientists can survey many galaxies from different points in the universe's very early history, they can have a better sense of how reionisation may have progressed.

"We're trying to understand how many galaxies do have this line - and that gives us some measure of when the universe itself was reionised," Illingworth said.

"One [galaxy] is interesting, but it's when you have 50 that you can really say something about what galaxies were really like then."
As astronomers push the limits of current telescopes and await the completion of NASA's James Webb Space Telescope, set for launch in 2018, scientists may soon find more of these galaxies even closer to the birth of the universe than this new record breaker.

"You don't get to be record holder very long in this business," Illingworth said, "which is good because ultimately we are trying to learn about the universe. So more is better."

View Article Here   Read More

Astronomers Measure Distance to Farthest Galaxy Yet

The farthest confirmed galaxy observed to date was identified in this Hubble image of a field of galaxies.  The inset image of the galaxy has been colored blue as suggestive of its young stars. Credit NASA/European Space Agency/Yale/University of California, Santa Cruz

Excerpt from nytimes.com

Leapfrogging backward in time to when the universe was apparently feeling its oats, a group of astronomers reported Tuesday that they had measured a bona fide distance to one of the farthest and thus earliest galaxies known.

The galaxy, more than a few billion light-years on the other side of the northern constellation Boötes, is one of the most massive and brightest in the early universe and goes by the name of EGS-zs8-1. 
It flowered into stardom only 670 million years after the Big Bang.
The light from that galaxy has taken 13 billion years to reach telescopes on Earth. By now, however, since the universe has continued to expand during that time, the galaxy is about 30 billion light-years away, according to standard cosmological calculations.
The new measurements allow astronomers to see the galaxy in its infancy. Despite its relative youth, however, it is already about one-sixth as massive as the Milky Way, which is 10 billion years old. And it is getting bigger, making stars 80 times faster than the Milky Way is making them today. The discovery was reported in The Astrophysical Journal by Pascal Oesch of Yale University and his colleagues.

By the rules of the expanding universe, the farther away a galaxy is, the faster it is retreating from us, measured by the “redshift” of its light being broadened to longer wavelengths, the way an ambulance siren seems to lower its pitch as it goes by.

In the past few years, as astronomers have raced one another into the past with instruments like the Hubble Space Telescope, galaxies have been found that appear even more distant. Those measurements, however, were estimates based on the colors of the objects — so-called photometric redshifts.

The new galaxy stuck out in a survey of distant galaxies by the Hubble and Spitzer space telescopes known as Candels, for Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. Its redshift was precisely measured with a powerful spectrograph known as Mosfire — Multi-Object Spectrometer for Infrared Exploration — on Keck 1, one of a pair of 10-meter-diameter telescopes on Mauna Kea in Hawaii. That makes it the highest redshift confirmed in this way, said Garth Illingworth, of the University of California, Santa Cruz, one of the astronomers in the study.

How galaxies were able to form and grow so rapidly after the lights came on in the universe is a mystery that will be addressed by a coming generation of instruments like the James Webb Space Telescope and the Thirty Meter Telescope, a goliath planned for Mauna Kea, already home to a dozen telescopes.

Recently, however, construction of the Thirty Meter Telescope, a $1.4 billion project, has been halted by protests by Hawaii residents who feel their mountain has been abused. An echo of that controversy appears in the new paper, in which Dr. Oesch and his colleagues write: “The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.”

View Article Here   Read More

Local Lick Observatory Astronomers Discover ‘Supersized Earths’ Surrounding Relatively Nearby Star

A telescope at Lick Observatory on Mount Hamilton. (CBS)
A telescope at Lick Observatory on Mount Hamilton. (CBS)

Excerpt from cbslocal.com

SAN JOSE (CBS SF) – Astronomers at the Lick Observatory atop Mount Hamilton have confirmed the existence of three planets described as “supersized Earths” orbiting a star 54 light years away.
Researchers from the University of California, University of Hawaii, the University of California Observatories and Tennessee State University have been working for years to confirm the planets were there.

The planets orbit a star called HD 7924. They orbit at a distance closer than Mercury orbits our sun (35.9 million miles), and complete their orbits in five, 15 and 24 days, respectively.
“The three planets are unlike anything in our solar system, with masses seven to eight times the mass of Earth and orbits very close to their host star,” UC Berkeley graduate student Lauren Weiss said in a written statement.

The researchers used a robotic telescope called the “Automated Planet Finder,” which searches for planets around nearby stars that could be suitable for life. Most distant planets discovered by astronomers so far are gas giants like Jupiter.

Astronomers first found evidence of planets surrounding HD 7924 six years ago. The planets are not visible to the naked eye.

View Article Here   Read More

Did natural selection make the Dutch the tallest people on the planet?

Dutch national women's field hockey team

Excerpt from news.sciencemag.org
ByMartin Enserink

AMSTERDAM—Insecure about your height? You may want to avoid this tiny country by the North Sea, whose population has gained an impressive 20 centimeters in the past 150 years and is now officially the tallest on the planet. Scientists chalk up most of that increase to rising wealth, a rich diet, and good health care, but a new study suggests something else is going on as well: The Dutch growth spurt may be an example of human evolution in action.
The study, published online today in the Proceedings of the Royal Society B, shows that tall Dutch men on average have more children than their shorter counterparts, and that more of their children survive. That suggests genes that help make people tall are becoming more frequent among the Dutch, says behavioral biologist and lead author Gert Stulp of the London School of Hygiene & Tropical Medicine.

"This study drives home the message that the human population is still subject to natural selection," says Stephen Stearns, an evolutionary biologist at Yale University who wasn't involved in the study. "It strikes at the core of our understanding of human nature, and how malleable it is." It also confirms what Stearns knows from personal experience about the population in the northern Netherlands, where the study took place: "Boy, they are tall."

For many years, the U.S. population was the tallest in the world. In the 18th century, American men were 5 to 8 centimeters taller than those in the Netherlands. Today, Americans are the fattest, but they lost the race for height to northern Europeans—including Danes, Norwegians, Swedes, and Estonians—sometime in the 20th century.

Just how these peoples became so tall isn't clear, however. Genetics has an important effect on body height: Scientists have found at least 180 genes that influence how tall you become. Each one has only a small effect, but together, they may explain up to 80% of the variation in height within a population. Yet environmental factors play a huge role as well. The children of Japanese immigrants to Hawaii, for instance, grew much taller than their parents. Scientists assume that a diet rich in milk and meat played a major role.

The Dutch have become so much taller in such a short period that scientists chalk most of it up to their changing environment. As the Netherlands developed, it became one of the world's largest producers and consumers of cheese and milk. An increasingly egalitarian distribution of wealth and universal access to health care may also have helped.

Still, scientists wonder whether natural selection has played a role as well. For men, being tall is associated with better health, attractiveness to the opposite sex, a better education, and higher income—all of which could lead to more reproductive success, Stulp says.
Yet studies in the United States don't show this. Stulp's own research among Wisconsinites born between 1937 and 1940, for instance, showed that average-sized men had more children than shorter and taller men, and shorter women had more children than those of average height. Taken together, Stulp says, this suggests natural selection in the United States pulls in the opposite direction of environmental factors like diet, making people shorter instead of taller. That may explain why the growth in average American height has leveled off.

Stulp—who says his towering 2-meter frame did not influence his research interest—wondered if the same was true in his native country. To find out, he and his colleagues turned to a database tracking key life data for almost 100,000 people in the country's three northern provinces. The researchers included only people over 45 who were born in the Netherlands to Dutch-born parents. This way, they had a relatively accurate number of total children per subject (most people stop having children after 45) and they also avoided the effects of immigration.

In the remaining sample of 42,616 people, taller men had more children on average, despite the fact that they had their first child at a higher age. The effect was small—an extra 0.24 children at most for taller men—but highly significant. (Taller men also had a smaller chance of remaining childless, and a higher chance of having a partner.)  The same effect wasn't seen in women, who had the highest reproductive success when they were of average height.  The study suggests this may be because taller women had a smaller chance of finding a mate, while shorter women were at higher risk of losing a child.

Because tall men are likely to pass on the genes that made them tall, the outcome suggests that—in contrast to Americans—the Dutch population is evolving to become taller, Stulp says. "This is not what we've seen in other studies—that's what makes it exciting," says evolutionary biologist Simon Verhulst of the University of Groningen in the Netherlands, who was Stulp's Ph.D. adviser but wasn't involved in the current study. Verhulst points out that the team can't be certain that genes involved in height are actually becoming more frequent, however, as the authors acknowledge.

The study suggests that sexual selection is at work in the Dutch population, Stearns says: Dutch women may prefer taller men because they expect them to have more resources to invest in their children. But there are also other possibilities. It could be that taller men are more resistant to disease, Stearns says, or that they are more likely to divorce and start a second family. "It will be a difficult question to answer.”

Another question is why tall men in Holland are at a reproductive advantage but those in the United States are not. Stulp says he can only speculate. One reason may be that humans often choose a partner who's not much shorter or taller than they are themselves. Because shorter women in the United States have more children, tall men may do worse than those of average height because they're less likely to partner with a short woman.

In the end, Stearns says, the advantage of tall Dutchmen may be only temporary. Often in evolution, natural selection will favor one trend for a number of generations, followed by a stabilization or even a return to the opposite trend. In the United States, selection for height appears to have occurred several centuries ago, leading to taller men, and then it stopped. "Perhaps the Dutch caught up and actually overshot the American men," he says.

View Article Here   Read More

Radio bursts from space reveal strange mathematical pattern

Excerpt from foxnews.com

Eleven fast radio bursts from space seem to follow a strange mathematical pattern, according to a new study – and it has researchers scratching their heads. 

According to study co–authors Michael Hippke of the Institute of Data Analysis in Neukirchen-Vluyn,  Germany, and John Learned of the University of Hawaii in Manoa, the bursts– which were first detected in 2001 – all had dispersion measures that were integer multiples of the same number: 187.5. “The astronomers that found [the bursts] have not seen such things before and do not understand them,” Learned told FoxNews.com.

Nobody knows what causes fast radio bursts, known as FRBs. They only last a few milliseconds, and only one so far has been captured live (by the Parkes Telescope in Australia last year). Though the bursts release just as much energy in a few milliseconds as the sun does in a month, their brevity indicates that the source must be small, with estimates being several hundred miles across at most.

Researchers use dispersion measures, which records how much “space gunk” the burst has passed through, to estimate the distance an FRB has travelled. For instance, a low frequency FRB will have more gunk on it, indicating a longer trip, whereas a high frequency FRB will be cleaner, indicating it came from closer to Earth.
The fact that all of the FRBs’ dispersion measures are integer multiples of 187.5 has, according to Hippke and Learned’s team’s calculations, a 5 in 10,000 chance of being coincidental. The dispersion measures also indicate that their origin is relatively close to Earth, but unlikely from within our own galaxy.

There are numerous theories on where these bursts came from, including speculation that the messages are from extraterrestrial intelligence. To the scientific community, however, this theory doesn’t really hold water, and is seen as more of a last resort only after all other avenues have been exhausted.

“We think these are likely from some very energetic process, like a burst from a high magnetic field neutron star or energy released [when] two neutron stars merge,” Professor Maura McLaughlin of the West Virginia University Center for Astrophysics explained. “The thing that made people think they were possibly from ETs was a recent paper that showed that one fundamental property is quantized in a way that wouldn't be expected if the signals were naturally occurring. However, I imagine that correlation will totally go away once more are discovered.”

Learned himself is dubious of an alien source as well, noting that he and Hippke only noted the dispersion measures’ “peculiar” pattern, and that they may even be coming from Earth. “We are now leaning more towards a terrestrial, anthropogenic interpretation,” he said. “At this point I would place my money on some sort of governmental satellite, not a natural phenomena, but I would not bet much.  More data, which reportedly [is] being analyzed but which we have no insider information about yet, will be most interesting and refute or confirm our hypotheses.” He also noted that he’d only look to an ETI interpretation once all other possibilities have been eliminated.

As for McLaughlin, she believes there’s no way the FRBs could be messages from aliens, as the signals are very broadband and emitted over a wide range of radio frequencies. “It would take a LOT of energy for an alien civilization to produce these bursts - they'd need to harness the energy of many, many suns - and there's no real advantage for communication to send a signal over such a large bandwidth.”

View Article Here   Read More

Shortest Total Lunar Eclipse of the Century Visible Early Saturday


Excerpt from space.com 
By Calia Cofield 

Don't forget to look skyward in the early hours of Saturday morning (April 4), to catch a glimpse of the shortest total lunar eclipse of the century.

The moon will be completely swallowed by Earth's shadow for just 4 minutes and 43 seconds on Saturday morning, according to NASA officials. During that time, the moon may change from its normal grayish hue to a deep, blood red. The total eclipse begins at 6:16 a.m. EDT (1016 GMT). You can watch a live webcast of the eclipse on the Slooh Observatory website, Slooh.com, or here at Space.com courtesy of Slooh, starting at 6 a.m. EDT (1000 GMT).
That color change can make for a dramatic display, especially for humans in the distant past, NASA officials said. 

"For early humans, [a lunar eclipse] was a time when they were concerned that life might end, because the moon became blood red and the light that the moon provided at night might have been taken away permanently," Mitzi Adams, an astronomer at NASA's Marshall Space Flight Center in Huntsville, Alabama, said during a news conference today (April 3). "But fortunately, [the light] always returned." 

The April 4 eclipse is the third in a series of four total lunar eclipses — known as a lunar tetrad — visible in the United States. Each of the eclipses is separated by about 6 months. The final installment of this four-eclipse series will occur on Sept. 28. Saturday's lunar eclipse follows closely behind the total solar eclipse that took place on March 20.

Earth's shadow has an outer ring, called the penumbra, and an inner core, called the umbra. Where the moon passes into the penumbra, it appears dark, as if a bite had been taken out of it. When the moon passes though the umbra, it turns a deep, red color.

A total lunar eclipse occurs when the moon is totally submerged in the umbra. On Saturday, the moon will begin to enter the umbra at about 6:16 a.m. EDT (1016 GMT) but will not be completely covered by the shadow until about 7:57 EDT (1157 GMT), after the moon has set in most locations east of the Mississippi River.

While the total eclipse will last less than five minutes, the moon will be partially submerged in the umbra for about one hour and 40 minutes. The dark shadow of the penumbra will first be visible on the moon's surface starting at about 5:35 a.m. EDT (0935 GMT), according to Sky and Telescope magazine.

Viewers west of the Mississippi River will be able to see the total lunar eclipse, starting at about 4:57 a.m. PDT (1157 GMT). Skywatchers in Hawaii and western Alaska will be able to watch the entire eclipse, from the moon's entrance to its exit from the penumbra.

Viewing Guide for Total Lunar Eclipse, April 4, 2015
This world maps shows the regions where the April 4 total lunar eclipse will be visible. The best viewing locations are in the Pacific Ocean.

This weekend's eclipse is extremely short because the moon is only passing through the outskirts of the umbra. (The shortest total lunar eclipse in recorded history, according to Adams, was in 1529 and lasted only 1 minute and 41 seconds).

The eclipse will not be visible in Europe or most of Africa. The partial eclipse will be visible in all except the easternmost parts of South America. The best viewing locations for the total eclipse will be in the Pacific region, including eastern Australia, New Zealand and other parts of Oceania.

View Article Here   Read More

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

View Article Here   Read More

Astronomers find star speeding out of the galaxy

(Reuters) - Astronomers have found a star hurtling through the galaxy faster than any other, the result of being blasted away by the explosion of a massive partner star, researchers said on Thursday.
The star, known as US 708, is traveling at about 746 miles (1,200 km) per second, fast enough to actually leave the Milky Way galaxy in about 25 million years, said astronomer Stephan Geier with Germany-based European Southern Observatory, which operates three telescopes in Chile.

"At that speed you could travel from Earth to the moon in five minutes," noted University of Hawaii astronomer Eugene Magnier.
US 708 is not the first star astronomers have found that is moving fast enough to escape the galaxy, but it is the only one so far that appears to have been slingshot in a supernova explosion.

The 20 other stars discovered so far that are heading out of the galaxy likely got their impetus from coming too close to the supermassive black hole that lives at the center of the Milky Way, scientists report in an article in this week’s edition of the journal Science.

Before it was sent streaming across the galaxy, US 708 was once a cool giant star, but it was stripped of nearly all of its hydrogen by a closely orbiting partner. Scientists suspect it was this feeding that triggered the partner’s detonation.

If confirmed, these types of ejected stars may provide more insight into how supernova explosions occur. Since the explosions give off a fairly standard amount of radiation, scientists can calculate their distances by measuring how bright or dim they appear and determine how fast the universe is expanding.

View Article Here   Read More

Cluster Filled with Dark Matter May House ‘Failed Galaxies’

The Coma Cluster

Excerpt space.com

A strange set of 48 galaxies appears to be rich in dark matter and lacking in stars, suggesting that they may be so-called "failed" galaxies, a new study reports.

The galaxies in question are part of the Coma Cluster, which lies 300 million light-years from Earth and packs several thousand galaxies into a space just 20 million light-years across. To study them, Pieter van Dokkum of Yale University and his colleagues used the Dragonfly Telephoto Array in New Mexico.

The array's eight connected Canon telephoto lenses allow the researchers to search for extremely faint objects that traditional telescope surveys miss. Often, such as when the researchers used the array to search for the faint glow that dark matter might create, the hunt comes up empty. 

But when van Dokkum and his colleagues looked toward the Coma Cluster, they found a pleasant surprise.

"We noticed all these faint little smudges in the images from the Dragonfly telescope," van Dokkum told Space.com.

The mysterious blobs nagged at van Dokkum, compelling him to look into the objects further. Fortuitously, NASA's Hubble Space Telescope had recently captured one of these objects with its sharp eye. 

"It turned out that they're these fuzzy blobs that look somewhat like dwarf spheroidal galaxies around our own Milky Way," van Dokkum said. "So they looked familiar in some sense … except that if they are at the distance of the Coma Cluster, they must be really huge."

And with very few stars to account for the mass in these galaxies, they must contain huge amounts of dark matter, the researchers said. In fact, to stay intact, the 48 galaxies must contain 98 percent dark matter and just 2 percent "normal" matter that we can see. The fraction of dark matter in the universe as a whole is thought to be around 83 percent. 

But before making this claim, the team had to verify that these blobs really are as distant as the Coma Cluster. (In fact, the team initially thought the galaxies were much closer.). But even in the Hubble image the stars were not resolved. If Hubble — one of the most powerful telescopes in existence — can't resolve the stars, those pinpricks of light must be pretty far away, study team members reasoned. 

Now, van Dokkum and his colleagues have definitive evidence: They've determined the exact distance to one of the galaxies. The team used the Keck Telescope in Hawaii to look at one of the objects for two hours. This gave them a hazy spectrum, from which they were able to tease out the galaxy's recessional velocity — that is, how fast it is moving away from Earth.

That measure traces back to the Hubble Telescope's namesake. In 1929, American astronomer Edwin Hubble discovered one of the simplest and most surprising relationships in astronomy: The more distant a galaxy, the faster it moves away from the Milky Way.

Today, astronomers use the relationship to measure a galaxy's recessional velocity and thus calculate the galaxy's distance. In this case, the small fuzzy blob observed with Keck was moving away from Earth at 15.7 million mph (25.3 million km/h). That places it at 300 million light-years away from Earth, the distance of the Coma Cluster.

So the verdict is officially in: These galaxies must be associated with the Coma Cluster and therefore must be extremely massive.
"It looks like the universe is able to make unexpected galaxies," van Dokkum said, adding that there is an amazing diversity of massive galaxies.

But the clusters still present a mystery: The team doesn't know why they have so much dark matter and so few stars.

Though they look serene and silent from our vantage on Earth, stars are actually roiling balls of violent plasma. Test your stellar smarts with this quiz.
One possibility is that these are "failed" galaxies. A galaxy's first supernova explosions will drive away huge amounts of gas. 

Normally, the galaxy has such a strong gravitational pull that most of the expelled gas falls back onto the galaxy and forms the next generations of stars. But maybe the strong gravitational pull of the other galaxies in the Coma Cluster interfered with this process, pulling the gas away.

"If that happened, they had no more fuel for star formation and they were sort of stillborn galaxies where they started to get going but then failed to really build up a lot of stars," said van Dokkum, adding that this is the most likely scenario. 

Another possibility is that these galaxies are in the process of being ripped apart. But astronomers expect that if this were the case, the galaxies would be distorted and streams of stars would be flowing away from them. Because these effects don't appear, this scenario is very unlikely.

The next step is to try to measure the individual motions of stars within the galaxies. If the team knew those stars' speeds, it could calculate the galaxies' exact mass, and therefore the amount of dark matter they contain. If the stars move faster, the galaxy is more massive. And if they move slower, the galaxy is less massive. 
However, this would require a better spectrum than the one the team has right now.

"But it's not outside the realm of what's possible," van Dokkum assured. "It's just very hard."

The original study has been published in Astrophysical Journal Letters. You can read it for free on the preprint site arXiv.org.

View Article Here   Read More

Older posts

Creative Commons License
This work is licensed under a
Creative Commons Attribution 4.0
International License
unless otherwise marked.

Terms of Use | Privacy Policy

Up ↑