Maryland legislature sends fracking ban bill to Gov. Larry Hogan

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Marylanders are using more natural gas than ever, but the state legislature has drawn the line at producing it. The Democrat-controlled General Assembly gave final approval late Monday to a bill that would impose a statewide ban on hydraulic fracturing, sending the legislation to Republican Gov. Larry Hogan, who announced earlier this month that he […]

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March 30, 2017 at 12:27AM

Wrong-way asteroid plays ‘chicken’ with Jupiter

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Credit: IB Times

It’s not yet known what the origin of asteroid (or comet) ‘Bee-Zed’ is or if it’s one of a class of similar objects in retrograde co-orbital resonance, as Phys.org reports. The researchers say ‘how it got there remains a mystery.’

For at least a million years, an asteroid orbiting the “wrong” way around the sun has been playing a cosmic game of chicken with giant Jupiter and with about 6,000 other asteroids sharing the giant planet’s space, says a report published in the latest issue of Nature.

The asteroid, nicknamed Bee-Zed, is the only one in this solar system that’s known both to have an opposite, retrograde orbit around the sun while at the same time sharing a planet’s orbital space, says researcher and co-author Paul Wiegert of Western’s Department of Physics and Astronomy.

All but 82 of the million or so known asteroids in our solar system travel around the sun in what’s called a prograde motion: that is, counter-clockwise when visualized from above. But asteroid 2015 BZ509 (“Bee-Zed” for short) circles clockwise, in a retrograde motion—moving against the flow of all other asteroids in the giant planet’s orbital entourage.

Put another way, it’s as if Jupiter is a monster truck on a track circling the sun, and the asteroids in Jupiter’s orbit are sub-compact cars all whizzing along in the same direction. Bee-Zed is the rogue—driving around the track in the wrong direction—steering between the 6,000 other cars and swerving around the monster truck. And it does so every single lap, and has done so for thousands of laps for a million years or more.

So how does it avoid colliding with Jupiter? Jupiter’s gravity actually deflects the asteroid’s path at each pass so as to allow both to continue safely on their way, Wiegert says.

Little is known about the asteroid, which was discovered in January, 2015. It has a diameter of about three kilometers and it may have originated from the same place as Halley’s comet, which also has a retrograde orbit. The team hasn’t been able to determine yet if Bee-Zed is an icy comet or a rocky asteroid.

But their analysis—based on complex calculations and on observations through the Large Binocular Camera on the Large Binocular Telescope in Mt. Graham, Arizona, during a span of 300 days—show Bee-Zed is somehow able to maintain a stable orbit even as an outlier. The calculations conducted by the team show the orbit has been stable for at least a million years and will be stable for at least a million more.

Learning more about the asteroid provides another intriguing glimpse into previously unknown and unmapped features of our solar system. “The detective work has just begun,” he said.

Source: Wrong-way asteroid plays ‘chicken’ with Jupiter | Phys.org

Video: Trojan Asteroids: Jupiter’s Prisoners

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March 29, 2017 at 11:45PM

PhDs – Making use of the vast pool of skilled retired people

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As a society we use PhDs as a way to provide additional university level training to young people. Young people who have never seen a real job, do not understand the world outside education and are generally fairly wet-behind the … Continue reading →

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March 29, 2017 at 10:34PM

New Paper Indicates Antarctica Has Been Gaining Ice Mass Since 1800

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Antarctica Has Been Gaining Ice,

Lowering Sea Level For Centuries

“Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away”

— NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses

For decades scientists have suggested that the effects of a climatic warming would likely lead to an increase in Antarctica’s surface mass balance (i.e., mass gains exceed losses), and this would lead to a concomitant lowering of sea levels.

Oerlemans, 1982

“The results indicate that a climatic warming will probably lead to a sea-level lowering of some tens of centimetres in the next centuries. This is because for Antarctic conditions the increase in snow accumulation exceeds the increase in melting.”

Huybrechts and Oerlemans, 1990

“According to this mass balance model, the amount of accumulation over the entire ice sheet is presently 24.06 x 10¹¹ m³ of ice, and no runoff takes place.  A 1°C uniform warming is then calculated to increase the overall mass balance by an amount of 1.43 10¹¹ m³ of ice, corresponding to a lowering of sea level with 0.36 mm/yr. A temperature increase of 5.3° C is needed for the increase in ablation to become more important than the increase in accumulation and the temperature would have to rise by 11.4°C to produce a zero surface mass balance.”

Huybrechts et al., 2004

“As a general result, it is found that the effect of increased precipitation on Antarctica dominates over the effect of increased melting on Greenland for the entire range of predictions, so that both polar ice sheets combined would gain mass in the 21st century. The results are very similar for both time-slice patterns driven by the underlying time evolution series with most of the scatter in the results caused by the variability in the lower-resolution AOGCMs. Combining these results with the long-term background trend yields a 20th and 21st century sea-level trend from polar ice sheets that is however not significantly different from zero.”

Lenaerts et al. 2016

“We present climate and surface mass balance (SMB) of the rctic ice sheet (AIS) as simulated by the global, coupled ocean–atmosphere–land Community Earth System Model (CESM) with a horizontal resolution of ∼1∘ in the past, present and future (1850–2100). … CESM [Community Earth System Model] projects an increase of Antarctic ice sheet SMB [surface mass balance] of about 70 Gtyear−1 per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet’s edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content.”

“In contrast to Greenland, where increased snowfall currently does not compensate enhanced surface runoff, this increase in AIS snowfall translates almost fully to ice sheet mass gain and mitigation of sea-level rise (Bengtsson et al. 2011; Shepherd et al. 2012). The reason is that rainfall on the AIS remains small, and most of the liquid water produced by surface melt can refreeze in the snowpack. Even in a warmer future, projected surface runoff losses are dominated by mass gains through enhanced snowfall (Ligtenberg et al., 2013).”

Thomas et al., 2017

“The central Antarctic sites lack coherency and are either not representing regional precipitation or indicate the models inability to capture relevant precipitation processes in the cold, dry central plateau. The drivers of precipitation are reviewed for each region and the temporal variability and trends evaluated over the past 100, 200 and 1000 years. Our study suggests an overall increase in SMB [surface mass balance] across the grounded Antarctic ice sheet of ~ 44 GT since 1800 AD, with the largest (area-weighted) contribution from the Antarctic Peninsula (AP).”

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March 29, 2017 at 09:33PM