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New look at Voyager data indicates that Uranus may have two more moons

October 26, 2016 Leave a comment
uranus-with-rings-and-moons-hubble-space-telescope-courtesy-wikimedia
This Hubble Space Telescope image of Uranus shows the planet surrounded by its four major rings and by 10 of its 27 known satellites. The false-color image was generated by Erich Karkoschka using data obtained by Hubble’s Near Infrared Camera and Multi-Object Spectrometer. Image courtesy NASA, Jet Propulsion Laboratory, Space Telescope Science Institute

Researchers at the University of Idaho say that Uranus, the distant gas giant known for being tipped by 90 degrees, might have two more moons than has previously been thought.

UI physics graduate student Robert O. Chancia and an assistant professor of physics at the university, Dr. Matthew M. Hedman, analyzed data obtained when Voyager 2 transmitted radio waves through Uranus’ rings.

They also looked at changes in the amount of light from distant stars that moves through the planet’s ring system.

Chancia and Hedman found that patterns in the distribution of ring material near the edges of Uranus’ alpha and beta rings vary over time, indicating that small moons may be present.

Dr. Richard G. French, a professor of astrophysics and director of the Whitin Observatory at Wellesley College in Massachusetts, said in an email message that the two UI scientists essentially used a meticulous process of comparison to determine that the pattern was caused by moons.

“Chancia and Hedman compared the wavelike properties from ring profiles taken at slightly different times and different geometries to work backwards to infer the properties of a nearby moon that might produce the satellite wakes,” he wrote.

Hedman pointed out that the results obtained when ground-based receiving stations interpreted the patterns of radio waves after they passed through the two rings shows that the waves were diffracted to varying degrees.

“When you look at this pattern in different places around the ring, the wavelength is different — that points to something changing as you go around the ring,” Hedman said. “There’s something breaking the symmetry.”

The researchers concluded that two possible small moonlets close to Uranus may be the culprits.

“We find for both rings that a moonlet located about 100 [kilometers] exterior to each ring could cause the optical depth variations seen in their occultation scans,” they write in the paper.

French explained that the proposed moons would be quite close to the alpha and beta rings.

“In this case, both moons are slightly exterior to the rings, so they orbit slightly more slowly than the rings themselves,” he wrote in an email message. “As the ring particles pass the moon, their orbits are slightly perturbed, resulting in a ripple pattern within the ring that is detectable as a periodic wavelike structure.”

Those “moonlet wakes” would help to maintain the structure of the Uranian rings, keeping them narrow. The rings are composed of a huge number of tiny particles, which  eventually spread out as collisions between them occur.

Moons near the rings can limit that effect.

French used the example of the planet that may be the solar system’s most famous example of a ring system to explain that a phenomenon called resonance could account for the confining  impact of small moons.

“If you are orbiting Saturn, for example, and you are a little ring particle and you orbit Saturn seven times and the little moon Prometheus six times in that same interval, that’s like getting pushed by the little finger on the swing,” he said. “That little push might be teeny but collectively is powerful. That’s kind of the notion that Matt and his student came up with. Those moons are in the right place to produce this wave pattern inside the rings.”

Chancia said in an email message that he and Hedman are not certain that such moonlet wakes occur in Uranus’ alpha and beta rings.

“We really just wanted to point it out as a possibility, because no one has come up with a universally accepted solution to how these rings are confined,” he wrote. “Anyway, the structures we found look like moonlet wakes.”

If they exist, the two moons would be Uranus’ smallest known and would have a diameter of four to 14 kilometers.

uranus-ring-scheme-courtesy-wikimedia
This diagram shows the Uranian ring scheme. Solid lines depict the rings, while dashed lines indicate the orbital paths of satellites. Graphic courtesy Wikimedia.
uranus-rings-image-courtesy-nasa
This silhouetted image of the rings of Uranus was taken by the Voyager 2 spacecraft on Jan. 24, 1986. A half-second exposure was made with the wide-angle camera at a distance of 63,300 kilometers (39,300 miles). This image shows the nine originally known rings appearing as dark lines against the brighter clouds of the planet. The most prominent ring, called epsilon, appears at the right; barely visible at the left are the three rings known simply as 4, 5 and 6. The resolution of the image is about nine kilometers (five miles). Image courtesy NASA, Jet Propulsion Laboratory.

The proposed moons, if they are there, were not seen by Voyager 2’s cameras. One reason is that the moons are likely so small that the 1970s-vintage equipment could not detect them.

“[G]iven the small predicted sizes of the ∝ and ß moonlets, a convincing detection may not be possible in the Voyager 2 images,” wrote Chancia and Hedman in their paper.

The two newly-hypothesized Uranian moons may also have a very low albedo,  which would make imaging of them difficult. Like the rings to which they are adjacent, they would not reflect much sunlight because the material from which they are constructed is not especially reflective.

“We know that the Uranian rings are dark because we can compare the amount of  light they block during a stellar occultation – a measure of how much material there is in the rings – with how bright they are in reflected sunlight,” French wrote in an email.

“The answer is that they are quite dark – they are not composed of pure water ice, and it’s likely that they are darkened by dust contamination and perhaps by charged particles in the Uranian environment.”

French explained that the two moons proposed by Chancia and Hedman are likely to exhibit the same characteristic.

“If the satellites are dark, too, then they are stealth objects,” he said. “They are also bloody far away.”

Uranus has 27 known moons, all named for literary characters in William Shakespeare’s plays, and 13 rings that have widths between one and 100 kilometers.

The planet’s ring system was discovered in 1977 by ground-based observers using the Kuiper Airborne Observatory.

Voyager 2 was launched in 1977. Voyager 1, a twin outer solar system probe, was sent into space the same year. The latter has now left the solar system and Voyager 2 is likely to do so within the next few years.

The Chancia and Hedman paper is to be published in The Astronomical Journal and appears online at ArXive.

Update, Oct. 26, 2017, 2:42 pm MDT: The word “part” was changed to the word “particle” in a quote by Professor Richard G. French in order to reflect the correct quotation.

NASA says Hubble data indicates possible water plumes on Europa

September 27, 2016 Leave a comment
europa-with-water-vapor-at-7-oclock-position-jan-26-2014-composite-image-image-of-europa-superimposed-on-hubble-data-courtesy-nasa-esa-w-sparks-stsci-usgs-astrogeology-science-center
This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes were photographed by the Hubble Space Telescope Imaging Spectrograph and were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the suspected plumes, which rise at least 160 kilometers above Europa’s icy surface, to be observed. The Hubble STIS data was obtained on Jan. 26, 2014. The image of Europa is superimposed on the Hubble STIS data and was assembled from data gathered during the Galileo and Voyager missions. Image courtesy NASA, European Space Agency, Space Telescope Science Institute/W. Sparks, U.S. Geological Survey Astrogeology Science Center.

NASA announced Monday that scientists using the Hubble Space Telescope have found evidence of water plumes on Europa, which means that spacecraft may be able to explore the moon’s ocean without the need to penetrate its icy surface.

A research team led by astronomer William Sparks of the Space Telescope Science Institute in Baltimore used a technique that has often been instrumental in discovering exoplanets to identify the plumes.

As an exoplanet moves in front of its star, the light from that star changes as it passes through the exoplanet’s atmosphere. This happens because the light encounters a variety of molecules.

europa-transit-illustration-courtesy-a-field-stsci
This image from a STScI animation shows Europa as it transits Jupiter. Animation courtesy Space Telescope Science Institute, animation by A. Field.

On Europa, Sparks and his team noticed that the molecules in the moon’s atmosphere included water vapor. That led them to embark on a quest to determine whether water from Europa’s subsurface ocean is being expelled into space.

The scientists observed Europa pass in front of Jupiter, from which the Sun’s light would be reflected through the atmosphere of the Jovian moon, ten times in 15 months. On three of the occasions water vapor was detected.

“This is an exciting find because it potentially gives us access to the ocean below,” Sparks said at a NASA teleconference on Monday.

Scientists are interested in sampling Europa’s ocean because it may provide indications of whether the moon is, or ever has been, hospitable to life.

“On Earth, life is found wherever there is energy, water, and nutrients, so we have a special interest in any place that has those characteristics,” Dr. Paul Hertz, director of NASA’s astrophysics division in Washington, D.C., said. “Europa might be such a place.”

Europa has a large sub-surface ocean that is thought to contain more water than all of the oceans on Earth. However, the satellite also has a thick icy crust atop that ocean.

The water plumes may rise as high as 200 kilometers off Europa’s surface.

“Europa’s ocean is considered to be one of the most promising places that could potentially harbor life in the solar system,” Geoff Yoder, the acting associate administrator for NASA’s Science Mission Directorate, said. “These plumes, if they do indeed exist, may provide another way to sample Europa’s subsurface.”

A team led by Lorenz Roth of the Southwest Research Institute in Austin, Tex. identified water plumes rising from Europa’s south pole once during 2012.

The Roth group used the Hubble Space Telescope’s Imaging Spectrograph to identify hydrogen and oxygen ions by the ultraviolet radiation they emit after particles accelerated by Jupiter’s magnetic field split water molecules in the Europan atmosphere.

The STScI group also used the STIS instrument, but instead obtained imagery of Europa’s atmosphere in ultraviolet light.

“It’s a technique that complements the Roth team’s,” Dr. Jennifer J. Wiseman, an astrophysicist at NASA’s Goddard Space Flight Center and the agency’s senior scientist assigned to the Hubble Space Telescope, said.

Wiseman explained that STIS’ ultraviolet imaging capacity was particularly helpful to the STScI researchers.

“In ultraviolet light, the surface of Jupiter looks more uniform in color than in visible light, so that allowed the Sparks team to more clearly see the silhouette image of the possible plumes on Europa as the moon passed in front of the smooth Jupiter background,” she wrote in an email message.

The Roth team also used STIS during their quest for Europa’s plumes in 2012.

Sparks said that, notwithstanding a different methodology of investigation, the STScI results are similar to those found by Roth and his colleagues.

“When we calculate in a completely different way the amount of material that would be needed to create these absorption features, it’s pretty similar to what Roth and his team found,” he explained. “The estimates for the mass are similar, the estimates for the height of the plumes are similar. The latitude of two of the plume candidates we see corresponds to their earlier work.”

comparison-of-2014-transit-and-2012-europa-aurora-observations-transit-on-left-lorenz-roth-team-image-on-right-courtesy-nasa-esa-w-sparks-left-image-l-roth-right-image
These images compare the 2014 transit observed by the STSI team (left) and the 2012 spectroscopy obtained by the Roth team (right). Images courtesy NASA, European Space Agency, W. Sparks (left), L. Roth (right).

The STScI and Roth teams have not seen plumes erupting from Europa at the same times. Sparks and his colleagues observed what they believe to be water plumes in January, March, and April, 2014.

Wiseman said that detection of Europa’s plumes is difficult.

“Such plumes would be faint, probably intermittent, and the ultraviolet wavelengths of light being observed are at the high frequency edge of what Hubble can detect,” she wrote in an email message.

Sparks explained that he and his team do not claim that their work proves the plumes’ existence, though he also said Monday that he does not believe that any other explanation for the findings his team made is likely.

“In a formal sense, we have a statistically significant result,” Sparks said. “The problem is that there may be something we don’t understand about the instrument or the scene. It’s more of a subjective uncertainty than a quantitative uncertainty.”

“I’m not aware of any other plausible natural explanation for the appearance of these patches of absorption,” he continued.

Two of the water plumes that were apparently observed by Sparks and his team occurred near the south pole of Europa and one was seen near the moon’s equator.

A paper detailing the findings by the STScI team will be published in the Sept. 29 edition of Astrophysical Journal.

Saturn’s moon Enceladus is the only body in the solar system known to eject water vapor to space.

Imagery obtained by the Galileo spacecraft during the late 1990s indicated that Europa has an ocean. Observation of the moon’s magnetic fields confirmed its existence.

Wiseman said during Monday’s teleconference that NASA plans to use the James Webb Space Telescope, due to be launched in 2018, to further investigate the possible water plumes of Europa.

james-webb-space-telescope-to-launch-in-2018-courtesy-nasa
The James Webb Space Telescope will be launched in 2018. Artist’s conception courtesy NASA.

In addition, the European Space Agency’s Jupiter Icy Moon Mission (JUICE) and NASA’s planned Europa orbiter will have future opportunities to explore the Jovian satellite.

NOTE 1: This post was updated at 5:38 pm MDT on Sept. 27, 2016 to add a discussion of Dr. Jennifer Wiseman’s interview responses.

NOTE 2: This post was updated at 9:32 pm MDT on Sept. 27, 2016 to correct an inaccurate statement contained in the headline, correct several minor errors in the quotation of Dr. Jennifer Wiseman’s email communication, and correct the acronym applicable to the Space Telescope Science Institute.

NOTE 3: This post was updated at 9:37 pm MDT on Sept. 27, 2016 to clarify the difference between the Roth team’s use of the Hubble Space Telescope’s Imaging Spectrograph in 2012 and the STScI team’s use of that instrument in 2014.

Arctic sea ice reaches lowest extent of year

September 16, 2016 Leave a comment

The amount of summer sea ice in the Arctic fell this year to the second-lowest ever recorded by satellite.

NASA and the National Snow and Ice Data Center in Boulder, Colo. announced Thursday that the Arctic has reached its summer season low extent.

The 4.14 million square kilometers of ice measured on Sept. 10 is statistically tied with the minimum ice extent during the summer of 2007 for second place on the historic minimum list. This year’s minimum ice cover is more than two million square kilometers below the 1981-2010 mean.

Arctic Summer Minimum Sea Ice Extent Record, 2007-2016

YEAR EXTENT (millions of km2) DATE MEASURED
2012 3.39 Sept. 17
2016 4.14 Sept. 10
2007 4.15 Sept. 18
2011 4.34 Sept. 11
2015 4.43 Sept. 9
2008 4.59 Sept. 20
2010 4.62 Sept. 21
2014 5.03 Sept. 17
2013 5.06 Sept. 13
2009 5.12 Sept. 13
1979-2000 mean 6.70 Sept. 13
1981-2010 mean 6.22 Sept. 15
sea-ice-graph-sept-12-2016-graphic-courtesy-national-snow-and-ice-data-center
This graphic shows the minimum Arctic sea ice extent (according to a preliminary assessment) with the seasonal minimum in prior years. Graphic courtesy National Snow and Ice Data Center.

A statement released by NSIDC starkly described the conditions in the Arctic this summer:

“This year’s minimum extent is 750,000 square kilometers (290,000 square miles) above the record low set in 2012 and is well below the two standard deviation range for the 37-year satellite record.”

Cloudy skies and atmospheric pressure conditions slowed ice melt in June and July, which may have prevented this season from becoming the most ice-free summer ever observed from space.

“June and July are usually key months for melt because that’s when you have 24 hours a day of sunlight – and this year we lost melt momentum during those two months,” Walt Meier, a scientist at NASA’s Goddard Space Flight Center, said in a statement.

2016-arctic-sea-ice-minimum-sept-10-graphic-courtesy-nasa-goddard-space-center-visualization-studio-graphic-by-c-starr
This graphic shows the 2016 seasonal minimum, reached on Sept. 10, in comparison with the 1981-2010 average (shown by the gold-colored line). Graphic courtesy NASA Goddard Space Flight Center Scientific Visualization Studio; graphic by C. Starr.

The pace of melting accelerated in August when two cyclones crossed the Arctic Ocean.

Meier explained that these may have especially impacted the speed with which ice in the Chukchi and Beaufort seas melted.

The three-and-one-half decade long satellite record shows a marked decline in the mean extent of Arctic sea ice during each month of the year.

In fact, a paper published on Sept. 15 in the journal Remote Sensing of Environment concluded that no record for maximum Arctic sea ice extent has been set since 1986, while during the 37 years of satellite monitoring there have been 75 new minimum ice extent records set.

“The record makes it clear that the ice is not rebounding to where it used to be, even in the midst of winter,” Claire Parkinson, the lead author of that study and a senior climate scientist at GSFC, said.

Arctic sea ice ordinarily reaches its maximum reach for the year in March, late in the winter. The sun is not visible in the region during the winter and does not contribute much to warming of land and sea surfaces during that season.

NSIDC’s statement cautioned that the estimate released Thursday could be revised if late-summer winds or other factors causing ice melt impact the sea ice cover during the remaining days of summer.

The monitoring record dates to 1978.

Earth’s poles are the two regions of the planet that are most sensitive to warming of the atmosphere. As sea ice melts, more solar energy is absorbed by the Arctic Ocean. The deep and dark waters absorb about 90 percent of the sun’s energy that reaches them.

By contrast, expansion of sea ice during the colder autumn and winter months causes about 80 percent of the solar energy that hits the frozen surface of the region’s marine environment to be reflected to space.

 

August ties July for hottest month ever recorded, says NASA

September 12, 2016 Leave a comment
aug-2016-temperatures
This graphic shows deviations around the world from the 1951-80 mean temperature. Graphic courtesy NASA Goddard Institute for Space Studies.

August 2016 was the warmest month in recorded history, tying July 2016 for that distinction.

NASA said Monday that the mean worldwide temperature during August was 0.16 degrees Celsius hotter than the previous record-setting August and 0.98 degrees Celsius hotter than the average August between 1951-1980.

According to analysis completed by the agency’s Goddard Institute for Space Studies, August 2016 was the eleventh month in a row to reach a new high for that month’s average worldwide temperature.

gistemp-anomaly-aug-2016-v2
This graphic provides another visual indication of the worldwide temperature anomaly in August. Graphic by Gavin Schmidt, courtesy NASA Goddard Institute for Space Studies.

IUCN warns at Hawaii conservation meeting that four of six great ape species are at high risk of extinction

September 6, 2016 Leave a comment

The International Union for Conservation of Nature added the Eastern lowland gorilla (Gorilla berengei) to its list of critically endangered species Sunday, raising the number of great ape species that are on very cusp of extinction to four.

The three other critically endangered species of great apes are the Western gorilla (Gorilla gorilla), Bornean orangutan (Pongo pygmaeus), and Sumatran orangutan (Pongo abelii).

There are six species of great apes. The other two species – the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus) – are endangered.

G. berengei includes two subspecies. One of them, Grauer’s gorilla (G.b. graueri), has experienced a decline in population of nearly 80 percent since 1994. There are about 3,800 individuals left. The other, the Mountain gorilla (G.b. beringei), has a population of about 880 individuals.

“To see the Eastern gorilla – one of our closest cousins – slide towards extinction is truly distressing,” Inger Anderson, IUCN’s director general, said in a statement. “We live in a time of tremendous change and each IUCN Red List update makes us realize just how quickly the global extinction crisis is escalating.”

The great apes are man’s closest relatives in the natural world.

Chimpanzees and bonobos share about 98.8 percent of the human genome. Gorilla genes are about 98.4 percent identical to humans, while the orangutan genome is about 97 percent identical to man.

The IUCN announcement came at its annual conservation congress, a gathering of political leaders, conservationists, and others, in Honolulu, Hawaii.

U.S. agencies: July is hottest month in recorded history

August 26, 2016 Leave a comment
Land and Sea Surface Anomalies, July 2016

This graphic shows blended air and sea surface temperature anomalies around the world for July 2016. Temperature data is shown in degrees Celsius. Graphic courtesy NOAA National Centers for Environmental Information.

The records kept falling as July 2016 set new benchmarks for heat.

NASA said Aug. 16 that last month was not only the hottest July in recorded history, but also the hottest month known since temperature record-keeping began in 1880.

“It wasn’t by the widest of margins, but July 2016 was the warmest month since modern record keeping began in 1880,” Dr. Gavin Schmidt, director of the agency’s Goddard Institute for Space Studies, said. “It appears almost a certainty that 2016 also will be the warmest year on record.”

This July’s mean temperature was 0.1 degrees warmer than the previous July record holders that occurred in 2015, 2011, and 2009, according to NASA’s study.

The National Oceanic & Atmospheric Administration confirmed July’s status as the heat pacesetter for all months on Aug. 17.

NOAA said that July 2016 was 1.57 degrees Fahrenheit warmer than the average 20th century July and 0.11 degrees Fahrenheit above the previous record-holding month of July 2015.

That continued a decades-long trend for the month of the year that is the peak of summer in the northern hemisphere.

“July 2016 marks the 40th consecutive July with temperatures at least nominally above the 20th century average,” NOAA’s National Centers for Environmental Information said in a summary of the July temperature data. “July 1976 was the last time July global land and ocean temperatures were below average.”

The trend is not limited to every year’s July.

A new record for the warmest month of its kind has been set in each of the past ten months, according to NASA, dating back to October 2015.

NOAA pegged the hot streak at 15 record-setting months in a row.

The disparity is the result of differing methodologies used by the two agencies.

For the year of 2016 through the end of July, NOAA found that mean worldwide temperatures were 1.85 degrees Fahrenheit above the 20th century average.

The next-hottest January-July period came in 2014, when the average was 0.34 degrees F below this year’s measurement.

Both agencies use meteorological stations around the world to obtain air temperature data and ship- and buoy-based instruments to measure sea surface temperature. Antarctic research stations are also used to gather the data that underlies their monthly global temperature analysis reports.

Spacecraft in solar orbit regains contact with Earth

August 24, 2016 Leave a comment
STEREO image of whole sun, Feb. 2, 2011 - courtesy NASA

This image shows our sun’s far side. It was obtained by the STEREO probes on Feb. 2, 2011 at 23:56 UT. Image courtesy NASA.

A probe launched by NASA in 2006 has resumed communication with the agency after nearly 23 months of silence.

The STEREO-B spacecraft, which orbits the sun, lost contact with Earth on Oct. 1, 2014.

The Deep Space Network reestablished the link with STEREO-B at 6:21 pm EDT on Sunday.

The long interruption in communication with the spacecraft was most likely the result of a series of events that began with a test of its command loss timer. The device is a kind of automated switch that allows the spacecraft to recover after a hardware failure. It functions by re-setting the hardware if no commands are received for a certain period of time. In STEREO-B’s case, that re-set time was three days.

NASA explained a likely scenario for the communications failure at a website posted shortly after the loss of contact event and still available here. An animated film that provides one possible model for the probe’s communication failure is also available.

STEREO-B’s navigation system probably failed because it was unable to detect guide stars. This caused the probe’s high gain antenna to be pointed away from Earth, which meant that it could not receive a signal.  The breakdown in the star tracking system was likely the result of a failed laser.

“Basically, we made a mistake in not accounting for one of those individual lasers failing,” Dr. Joseph Gurman, the STEREO project scientist at NASA’s Goddard Space Flight Center, said. “The data still looked good coming out of the unit as a whole even though one laser was bad. That got us into a situation where the spacecraft was getting bad navigational information.”

STEREO-B remains in an uncontrolled spin, a problem for which there is not currently enough power available to correct. The spacecraft obtains energy by means of solar arrays that extend out from its main section.

Gurman explained that NASA scientists are not sure how much power the probe’s batteries can produce or whether they can be fully re-charged.

“We don’t know if the batteries are damaged,” he said. “We know they can take some charge.”

Whether the spacecraft’s instrumentation is still functional is also unknown.

“I would say that we know nothing about the state of the instruments at this point,” Gurman said.

NASA will proceed cautiously to investigate the STEREO-B probe’s status. What Gurman and his colleagues want to avoid is any command that would return STEREO-B to an uncontrolled spin.

“We have an inertial problem that is giving bad information to the control system on the spacecraft,” he said. “We have to proceed in a step-by-step method.”

The first step will be to figure out the extent to which the probe has, to put it metaphorically, any gas in its tank.

“We have to heat up the probably frozen fuel in the fuel tank,” Gurman explained. “We can proceed from there to use the thrusters to right our attitude by using the autonomy software.”

Gurman is optimistic, though, about the prospects for obtaining more data about the sun from STEREO-B. NASA’s prior experience with another spacecraft that experienced a communication failure – the Solar and Heliospheric Observatory – indicates that instruments can survive with little or no damage, even in the cold of space, for quite some time.

“On SOHO, there were 12 principal investigator experiments,” Gurman said. “Only one mechanism in one telescope was damaged in such a way that we really couldn’t use the instrument. There was one instrument that suffered some degradation. That’s about it. We’re cautiously optimistic that we’ll be able to regain most of the scientific capability, if not all, that we had before.”

In any case, the STEREO mission formally ended eight years ago, so any data obtained from STEREO-B is beyond what was expected at the time of launch.

“Anything we get is gravy, to say the least,” Gurman said.

The probe’s twin, STEREO-A, also revolves around our closest star.

STEREO is an acronym that shortens the twin probes’ formal name – Solar Terrestrial Relations Observatories.

 

United Nations says 2016 on track to be hottest year on record

July 22, 2016 Leave a comment

A United Nations agency has predicted that the planet’s recent streak of record-setting hot years will reach a new threshold this year.

The World Meteorological Organization also noted in the July 21 statement that the concentration of atmospheric carbon dioxide has reached “new highs.”

The current level of CO2 in the atmosphere exceeds 400 parts per million, a concentration not known on Earth since the Pliocene epoch, which ended about 1.8 million years ago.

In June the average concentration reached 407 parts per million, which was 4 ppm greater than in June 2015.

A WMO official pointed to the trend as a reason to emphasize public policies aimed at reducing greenhouse gas emissions.

“This underlines more starkly than ever the need to approve and implement the Paris Agreement on climate change, and to speed up the shift to low carbon economies and renewable energy,” Petteri Taalas, the agency’s secretary-general, said.

The WMO statement highlighted a streak of record-setting hot months in its prediction.

Two U.S. agencies, the National Oceanic & Atmospheric Administration and the National Aeronautics and Space Administration, have said that June 2016 was the hottest June on record.

NOAA also said that June was the 14th consecutive month to set a heat record.

“Another month, another record,” Taalas said. “And another. And another. Decades-long trends of climate change are reaching new climaxes, fueled by the strong 2015/2016 El Niño.”

Global Mean Surface Temperature, Jan. - Jun. 2016 - courtesy NASA

This color-coded Robinson projection map shows global surface temperature anomalies for the period that includes the first six months of 2016. Higher than normal temperatures are shown in red and lower then normal termperatures are shown in blue. Graphic courtesy NASA Goddard Institute for Space Studies.

Year-to-Date Global Average Temperature - courtesy NOAA

This graphic shows the deviation of year-to-date average global temperature through the end of June from the 20th century mean for the past several years, as well as for several other years since the late 1990s. Graphic courtesy National Oceanic & Atmospheric Administration.

WMO also pointed to reduced Arctic sea ice during summer months, increased precipitation in some regions, and widespread bleaching of coral reefs as indicators of the climate trend that is likely to put 2016 in the record books.

New report says world’s largest primate is on fast track to extinction

June 22, 2016 Leave a comment
Grauer's gorilla infant

An infant Grauer’s gorilla is carried on the back of an adult. Photo courtesy Wildlife Conservation Society, photo by A.J. Plumptre.

The eastern lowland gorilla, Earth’s largest primate, is in rapid decline and has seen its population decline by nearly 80 percent since the late 1990s. There are now fewer than 4,000 individuals of the subspecies remaining in the wild.

Such is the bleak conclusion of a report released in April.

Persistent war in the animal’s home range, which is limited to a forested region in eastern Democratic Republic of Congo, is the leading culprit for the rapid extermination of the great ape species.

“Since 1996, the entire range of Grauer’s gorilla has been consumed in conflict,” the report said. “This has resulted in an almost complete breakdown in government control, including wildlife protection activities.”

Grauer's gorilla - courtesy FFI, photo by Stuart Nixon

Image of adult Grauer’s gorilla courtesy Fauna & Flora International, photo by Stuart Nixon.

The civil war in DRC began in in the aftermath of the 1994 genocide event in Rwanda. Hundreds of thousands of refugees streamed into DRC. Upon arrival, they engaged in deforestation in the eastern region of the country. The inflow of Rwandans refugees also helped set off a conflict that killed millions of people between 1996-2003.

Although the war is over, the militias who participated in it have not disappeared. They control areas in the eastern DRC that are the only habitat for Grauer’s gorillas and, in that territory, they tolerate mining and engage in bushmeat hunting.

The mining, which is done on a small scale and often illegally, is aimed at extracting minerals used in the production of elecronic devices such as cellular phones, laptop computers, and gaming consoles.

Grauer’s gorillas, as well as chimpanzees, are hunted by the militia soldiers to feed the miners, which fund them, and themselves. Although protected by law, the large size of a Grauer’s gorilla means it can provide enough meat to feed multiple humans. Because the animal moves in a troop through its forested habitat, hunters can take multiple gorillas and feed even more humans.

Disarming the militias and imposing legal controls on the small-scale mining within Grauer’s gorilla habitat is a crucial step toward assuring the subspecies’ survival, said the report’s authors.

“Significantly greater efforts must be made for the government to regain control of this region of DRC,” Andrew Plumptre, a wildlife biologist with Wildlife Conservation Society and the lead author of the report, said. “In particular, the government needs to quickly establish Reserve des Gorilles de Punia and the Itombwe Preserve, and reinforce Kahuzi-Biega National Park efforts, which have community support, and to establish strong communication between [Institut Congolais pour la Conservation de la Nature] and the DRC military to tackle armed militias that control mining camps in Grauer’s gorilla heartland.”

The report also concluded that agriculture, poaching for body parts, and “socio-economic depression from over a decade of civil war” are contributing to the rapid decline of Grauer’s gorilla and other plant and animal species.

Stuart Nixon, a wildlife biologist at the United Kingdom’s Chester Zoo and a co-author of the report, emphasized that a speedy government response to these stressors is vital.

“Unless greater investment and effort is made, we face the very real threat that this incredible primate will disappear from many parts of its range in the next five years,” he said.

The most recent prior population survey of Gorilla beringei graueri occurred during the mid-1990s. Researchers concluded that a population of about 17,000 individuals remained at that time.

The current conflict is not the first occasion in which Grauer’s gorillas have suffered extensive losses at the hands of humans.

During the 1960s and 1970s many individuals were killed as grassland areas of their range were converted to agriculture and farmers used shotguns provided by the government of Zaire to kill the gorillas.

Gorilla beringei graueri is one of four gorilla subspecies. Like individuals of the other three subspecies, Grauer’s gorillas live in groups. They are thought to organize themselves into harem-like assemblages that include two males. A female matures at about eight years of age, while a male reaches full development after about 12 years.

A full-grown male Grauer’s gorilla can weigh up to 400 pounds.

Both females and males leave the group at maturity, with male Grauer’s gorillas staying together until each can attract females and form new groups. Females join a group or ally themselves with a single adult male.

Also known as the eastern lowland gorilla, Grauer’s gorilla is closely related to the smaller western lowland gorilla (Gorilla gorilla gorilla) that is endemic to central African forests.

The report’s authors recommend that the status of Gorilla beringei graueri be downgraded from endangered to critically endangered by the International Union for the Conservation of Nature.

A species listed as “critically endangered” is just one step, on the IUCN hierarchy of classification, from extinction in the wild.

The report was published by the Wildlife Conservation Society, Flora and Fauna International and the Congolese Institute for the Conservation of Nature.

 

Look up tonight to see first summer solstice strawberry moon since 1967

June 20, 2016 Leave a comment
June full moon

A June full moon is also called a “honey moon” because it appears amber-colored through Earth’s atmosphere.

Today’s summer solstice in the northern hemisphere does not bring only the longest day of the year. Night sky watchers also have the opportunity to see, for the first time in 49 years, a full moon on the first day of summer.

The full moon occurs about once each month. The lunar year – the amount of time it takes for the moon to cycle through 12 lunar cycles – is 354 days; the lunar cycle averages 29.53 days.

A full moon occurs when the sun, Earth, and the moon are nearly aligned. During most  full moons we see nearly all of one of the Moon’s hemispheres from our planet. We do not see all of that hemisphere during a typical full moon because, if we did, the sun, Earth, and moon would be so aligned as to result in a lunar eclipse.

The other hemisphere of the moon is never visible from Earth because the moon’s rate of  rotation is equal to the amount of time it takes to orbit our planet.

Because tonight’s full moon occurs in June, it is colloquially known as a “strawberry moon.” According to the 1918 book The American Boy’s Book of Signs, Signals and Symbols, the nickname originated with native Americans of the northeastern United States because June is the month in which strawberries were harvested.

According to a 2012 National Geographic article, “Europeans have dubbed [a June full moon] the rose moon, while other cultures named it the hot moon for the beginning of the summer heat.”

The summer solstice in the northern hemisphere is the one day of the year on which the sun will be directly overhead at noon at the Tropic of Cancer. The sun is never directly overhead at a latitude north of the Tropic of Cancer or south of the Tropic of Capricorn.

In Colorado and the rest of the Mountain Time Zone of North America, the sun will get to its annual highest point in the sky at 4:34 pm.

Earth at summer solstice

This graphic shows Earth’s northern hemisphere at the summer solstice. Graphic courtesy Space.com.

The sun is directly overhead at high noon above the Tropic of Capricorn on the winter solstice in the northern hemisphere.

The southern hemisphere experiences its summer solstice on that day and its winter solstice when the sun is directly overhead at the Tropic of Cancer.

CORRECTION, June 20, 2016, 5:24 pm MDT: This article originally stated that the last summer solstice full moon occurred in 1949, 67 years ago. That is not an accurate statement and the article has been edited to correct the error.

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