Ian O'Neill, Author at Universe Today

February 21, 2008December 26, 2015 by Ian O'Neill

Pulsars are Exploding Unexpectedly and “Magnetars” Might be to Blame

Pulsars are fast-spinning, highly radiating neutron stars. Most pulsars emit radio, X-ray and gamma radiation at regular intervals (usually periods of a few milliseconds to a few seconds), in fact many pulses keep the accuracy of the most accurate atomic clocks on Earth. However, occasionally, these rapidly rotating bodies undergo a violent change, blasting massive quantities of energy into space. Although short-lived (a fraction of a second), the observed explosion packs a punch of at least 75,000 Suns. Is this a natural process in the life of a pulsar? Is it a totally different type of cosmic phenomena? Researchers suggest these observations may be a different type of neutron star: magnetars disguised as pulsars (and without an ounce of dark matter in sight!)…

Neutron stars are a product of massive stars after a supernova. The star isn’t big enough to create a black hole (i.e. less than 5 solar masses), but it is big enough to create a tiny, dense and hot mass of neutrons (hence the name). Due to the “Pauli exclusion principal” – a quantum mechanical principal that prevents any two neutrons from having the same quantum characteristics within the same volume – neutron stars are also predicted to be very hot. Intense gravity forces matter into a tiny volume, but quantum effects are repelling the neutrons. After theÂ star has gone supernova, as neutron stars are so small (a radius of only 10 to 20 km), the small mass preserves the starsÂ angular momentum, resulting in a fast-spinning, highly radiating body.

Much of theÂ stars magnetism is also preserved, but in a vastly increased dense state. Neutron stars are therefore expected to have an intense magnetic field. It is in fact this magnetic field that helps to generate jets of emission from the magnetic poles of the rotating body, creating a beam of radiation (much like a lighthouse).

However, one of these flashing lighthouses has surprised observers… it exploded, blasting vast amounts of energy into space, and then continued to spin and flash as if nothing had happened. This phenomenon has recently been observed by NASA’s Rossi X-ray Timing Explorer (RXTE) and has been backed up by data from the Chandra X-ray Observatory.

There are in fact other classes of neutron star out there. Slow-spinning, highly magnetic “magnetars” are considered to be a separate type of neutron star. They are distinct from the less-magnetic pulsar as they sporadically release vast amounts of energy into space and do not exhibit the periodic rotation we understand from pulsars. It is believed that magnetars explode as the intense magnetic field (the strongest magnetic field believed to exist in the Universe) warps the neutron star surface, causing extremely energetic reconnection events between magnetic flux, causing violent and sporadic X-ray bursts.

There is now speculation that known periodic pulsars that suddenly exhibit magnetar-like explosions are actually the highly magnetic cousins of pulsars disguised as pulsars. Pulsars simply do not have enough magnetic energy to generate explosions of this magnitude, magnetars do.

Fotis Gavriil of NASA’s Goddard Space Flight Center in Greenbelt, and his colleagues analysed a young neutron star (called PSR J1846-0258 in the constellation Aquila). This pulsar was often considered to be “normal” due to its fast spin (3.1 revolutions per second), but RXTE observed five magnetar-like X-ray bursts from the pulsar in 2006. Each event lasted no longer than 0.14 seconds and generated the energy of 75,000 Suns. Follow up observations by Chandra confirmed that over the course of six years, the pulsar had become more “magnetar-like”. The rotation of the pulsar is also slowing down, suggesting a high magnetic field may be braking its rotation.

These findings are significant, as it suggests that pulsars and magnetars may be the same creature, just at different periods of a pulsars lifetime, and not two entirely different classes of neutron star…

Results of this research will be published in todayâ€™s issue of Science Express.

Source: AAAS Science Express

February 21, 2008December 26, 2015 by Ian O'Neill

Solar Variability Most Likely Not the Cause of Global Warming

The gradual increase in global temperatures is getting harder and harder to pin on the Sun and its energy output variability. The Sun hasÂ a variationÂ in how much energy it outputs but this variability is only about one tenth of one percent. The pattern of atmospheric heating since the 1960s is showing an increase with the increase inÂ human activity (industry, transportation, power generation)Â and neither are showing signs of slowing down…

At the American Association for the Advancement of Science (AAAS) meeting in Boston, many talks are focusing on climate change and the human impact on the Earth. Experts in solar science, climate modeling, and atmospheric science are exploring the issues surrounding what the main culprit behind the rapid rate of change in global temperatures could be. The sole energy input into the Earths atmosphere comes from the Sun; so many scientists have looked toward our star for the answers. The Sun does vary its output of energy (historically, this is obvious during long periods of solar inactivity, such as the Maunder Minimum in the 1600’s where hardly any sunspots were observed on the Sun – this reduction in activity has been linked to the “Little Ice Age” experienced during this time), but generally speaking, the net energy increase or decrease is very small.

The link between solar variability and global warming has taken another blow from analysis of historical samples of sediment containing radioactive carbon-14 and a beryllium isotope. Quantities of carbon-14 and beryllium-10 reflect solar activity as they are greatly affected by solar magnetic field strength. The Sun’s magnetic field is directly related to solar activity (and therefore sunspot population). These radioactive isotopes are created by the impact of cosmic rays in the Earths atmosphere, and should the solar magnetic field be strong (i.e. during periods of high activity), cosmic rays will be blocked, reducing the quantity of isotopes in the sediment.

However, results from this analysis appear inconclusive and no strong link can be found in favour of increased solar activity during periods of atmospheric heating.

Linking any atmospheric phenomenon with solar variability is a difficult task. Attempts to connect monsoons with the 11-year solar cycle for instance have failed in 150 years of trying. It would seem that, for now at least, any connection between increased solar energy output and global warming is tenuous at best.

Casper M. Ammann, climate modeler at the National Center for Atmospheric Research in Boulder, Colorado, points out that global temperatures are rising at a historic rate, and there remains no link between solar variability and global warming. He states that global warming has “nothing to do with changes in solar activity. Itâ€™s greenhouse gases. Itâ€™s not the sun that is causing this [climate] trend.”

Perhaps the only answer is to drastically cut back our dependence on fossil fuels to slow the rate of carbon dioxide production. Even if the Sun should decide to become inactive, as there appears to be very little relationship between solar output and global warming, we will not be able to escape the greenhouse gases heating up our climate.

Source: Physorg.com

February 20, 2008December 26, 2015 by Ian O'Neill

US Cruiser Strikes Dead Spy Satellite

Officials have confirmed that the US spy satellite, USA 193, has been hit by an anti-satellite missile fired from USS Lake Erie positioned west of the Hawaiian Islands in the mid-Pacific at 10.30pm (US Eastern Time) Wednesday night. Fears of the propellant hydrazine being released into the atmosphere prompted the military response. Although plans for the missile strike were hampered by bad weather, the launch appears to have gone ahead regardless.

The 10.30pm time window was chosen by the US so that should the first attempt fail, a second and then a third attempt could be carried out. The window was only 10 seconds long, and BBC correspondent Jonathan Beale, based in Washington, says this operation was hugely ambitious and likened it to “trying to fire a missile through the eye of a needle.”

It is hoped that the modified Standard Missile-3 (SM-3) successfully destroyed the large orbiting mass, containing 450kg (1,000lbs) of the poisonous propellant hydrazine. The SM-3 does not carry a warhead; it depends on its high velocity and weight to destroy the target. Travelling at a velocity of over 17,000 mph, on impact the missile and satellite should break up, creating debris and hopefully destroying the full fuel tank. Most of the debris is expected to burn up in the Earths atmosphere over the next 15 hours (or two Earth orbits), and all of it is expected to have re-entered over the next 40 days, eliminating the risk of the poisonous fuel falling to Earth. However, at least 24 hours will be needed to assess how successful the strike has been.

In an official statement, the Department of Defence has said, “A network of land-, air-, sea- and space-based sensors confirms that the U.S. military intercepted a non-functioning National Reconnaissance Office satellite which was in its final orbits before entering the Earth’s atmosphere […] At approximately 10:26 p.m. EST today, a U.S. Navy AEGIS warship, the USS Lake Erie, fired a single modified tactical Standard Missile-3, hitting the satellite approximately 247 kilometers (133 nautical miles) over the Pacific Ocean as it traveled in space at more than 17,000 mph.”

The missile strike has prompted anger from both Russia and China, as the nations see it as a provocative manoeuvre by the US, but US officials insist that the missile strike was not intended to showcase their anti-satellite technology and was not used to destroy any top-secret orbital weapon.

Sources: CNN, BBC

February 20, 2008December 26, 2015 by Ian O'Neill

Mysterious Mars Formation May be Caused by Bursts of Water

Many basin-like features observed on the Martian surface appear to have a fanned feature around possible inlets. Much like river deltas, scientists believe these Mars inlets have similar properties as their terrestrial counterparts, where the flow of water would slow into a basin reservoir, dropping suspended material and depositing it as silt, forming deltas. However, some Martian delta features have a stepped structure. This is not observed on the Earth, so how were they formed on Mars? Researchers suggest sudden flows of water may be to blame…

More and more evidence for ancient Mars water appears to be accumulating every day as images continue to be sent back from the numerous orbiting satellites and two rovers, Mars Explorer Rovers Opportunity and Spirit. Although recent findings suggest the water may have been poisonous to life on early Mars, reducing the likelihood of finding ancient microbial life, the nature and mechanics of water storage and release will be of tremendous value to understanding the evolution of the planets and perhaps helping future Mars colonies when tapping into a source of H₂O.

Using a laboratory experiment intended for science students, researchers from Utrecht University, in the Netherlands, were able to reproduce stepped river deltas by pouring water through a flume, filled with a hollowed out sand basin. On pouring water in bursts, sand sediment was eroded from the inlet channel and deposited in the basin reservoir. As the bursty water input continued, steps in the sediment were created as the sand was deposited in layers.

The research to be published in Nature (Feb. 21, 2008), “Martian stepped-delta formation by rapid water release,” is able to draw some parallels with images being sent back from the Mars Orbiter Laser Altimeter (MOLA) on board the Mars Global Surveyor (MGS) and characterize this one source of Martian water. Based on MOLA observations of fans of 20 kilometers in basins of 100 kilometer-scale on Mars, they calculated the conditions for the creation of a stepped fan and found that by comparing with sediment transportation models, that these stepped features would only take a few tens of years to form. This is in striking contrast to other hydrologic features on Mars that take anywhere between hundreds to millions of years to form. Stepped delta features would therefore require large volumes of fast-flowing water to be created.

One possible reason for this sudden release of water could be from sub-surface pressures, as explained by Erin R. Kraal, now a geosciences research scientist at Virginia Tech, “We suggest the water was released internally, such as hydrothermal water suddenly pushed to the surface.”

Although the search for life may have taken a serious blow, future Mars settlement planners will be enthusiastic about finding sites for aquifers to sustain future human exploration of the Red Planet.

Source: Physorg.com

February 20, 2008December 26, 2015 by Ian O'Neill

Building a Moon Base: Part 3 – Structural Design

mars_base_artist_conception.thumbnail.jpg

Building the first Moon base will be the biggest challenge mankind has ever embarked on. We can already speculate about the hazards, natural and manmade, associated with a human presence on the lunar surface. In response, we already have some habitat structures in mind – ranging from inflatable structures to underground burrows inside ancient lava vents. Now it is about time we seriously start designing our first habitat structure, protecting us from micrometeorites, sustaining terrestrial pressures and using locally mined materials where we can…

In Part 1 of this “Building a Moon Base” series, we looked at some of the more obvious hazards associated with building a base on another planet. In Part 2, we explored some of the current design concepts for the first manned habitat on the Moon. The designs ranged from inflatable structures, habitats that could be constructed in Earth orbit and floated to the lunar surface, to bases hollowed out of ancient lava tubes under the surface. All concepts have their advantages, but the primary function must be to maintain air pressure and reduce the risk of catastrophic damage should the worst happen. This third installment of the series deals with the basic design of a possible lunar base which optimizes space, makes maximum use of locally mined materials and provides protection from the constant threat of micrometeorites…

“Building a Moon Base” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

The key factors influencing structural designs of habitats on the Moon are:

One-sixth terrestrial gravity.
High internal air pressure (to maintain human-breathable atmosphere).
Radiation shielding (from the Sun and other cosmic rays).
Micrometeorite shielding.
Hard vacuum effects on building materials (i.e. out gassing).
Lunar dust contamination.
Severe temperature gradients.

In addition to addressing these issues, the lunar structures must be easy to maintain, inexpensive, easy to construct and compatible with other lunar habitats/modules/vehicles. To achieve inexpensive construction, as much local material must be used as possible. The raw material for inexpensive construction could be the plentiful quantities of regolith readily accessible on the lunar surface.

As it turns out, lunar regolith has many useful properties for construction on the Moon. To complement lunar concrete (as introduced earlier in Part 2), basic building structures may be formed from cast regolith. Cast regolith would be very similar to terrestrial cast basalt. Created by melting regolith in a mold and allowing it to cool slowly would allow a crystalline structure to form, resulting in highly compressive and moderately tensile building components. The high vacuum on the Moon would greatly improve the manufacturing process of the material. We also have experience here on Earth in how to create cast basalt, so this isn’t a new and untested method. Basic habitat shapes could be manufactured with little preparation of the raw materials. Elements like beams, columns, slabs, shells, arch segments, blocks and cylinders could be fabricated, each element having ten times the compressive and tensile strength of concrete.

There are many advantages to using cast regolith. Primarily, it is very tough and resistant to erosion by lunar dust. It could be the ideal material to pave lunar rocket launch sites and construct debris shields surrounding landing pads. It could also make ideal shielding against micrometeorites and radiation.

OK, now we have basic building supplies, from local material, requiring minimum preparation. It is not too hard to imagine that the process of fabrication cast regolith could be automated. Prior to a human even setting foot on the Moon, a basic, pressurized habitat shell could be created, waiting for occupation.

But how big should the habitat be? This is a very tough question to answer, but the upshot is that if any lunar habitat will be occupied for long periods, it will have to be comfortable. In fact, there are NASA guidelines stating that, for missions of longer than four months, the minimum volume required by each individual should be at least 20m³ (from NASA Man Systems Integration
Standards, NASA STD3000, in case you were wondering). Compare the needs of long-term habitation on the Moon with the short-term Gemini missions in the mid-1960’s (pictured). The habitable volume per crewmember in Gemini was a cosy 0.57m³… fortunately these early forays into space were short. Despite NASA regulations, the recommended volume per crewmember is 120m³, approximately the same as the living space on the International Space Station. A similar space will be required inside future habitats on the Moon for crew wellbeing and mission success.

From these guidelines, habitat designers can work on how best to create this living volume. Obviously, floor space, habitat height and functionality will need to be optimized, plus space for equipment, life support and storage will need to be factored in. In a basic habitat design by F. Ruess, J. SchÃ¤nzlin and H. Benaroya from a publication entitled “Structural design of a lunar habitat” (Journal of Aerospace Engineering, 2006), a semi-circular, “hangar” shape is considered (pictured).

The shape of a load-bearing arch is a close ally for structural engineers, and arches are expected to be a major component for habitat design as structural stresses can be evenly distributed. Of course, architectural decisions such as the stability of the underlying material and slope angle would have to be made whilst building the habitat foundations, but this design is expected to address many of the issues associated with lunar construction.

The biggest stress on the “hangar” design will come from internal pressure acting outward, and not from gravity acting downward. As the habitat interior will need to be held at terrestrial pressures, the pressure gradient from interior to the vacuum of the exterior would exert a massive strain on the construction. This is where the arch of the hangar becomes essential, there are no corners, and therefore no weak spots can degrade integrity.

Many more factors are considered, involving some complex stress and strain calculations, but the above description gives a taste as to what structural engineers must consider. By constructing a rigid habitat from cast regolith, the building blocks for a stable construction can be built. For added protection from solar radiation and micrometeorites, these arched habitats could be built side-by-side, interconnecting. Once a series of chambers have been built, loose regolith could be laid on top. The thickness of the cast regolith will also be optimized so the density of the fabricated material can provide extra protection. Perhaps large slabs of cast regolith could be layered on top.

Once the basic habitat modules are constructed, the layout of the settlement can begin. Lunar “city planning” will be another complex task and many module configurations must be considered. Five main module configurations are highlighted: Linear, Courtyard, Radial, Branching and Cluster.

The infrastructure of the future lunar settlement depends on many factors, however, and will be continued in the next instalment.

“Building a Base Moon” is based on research by Haym Benaroya and Leonhard Bernold (“Engineering of lunar bases“)

Article based on published work by Haym Benaroya and Leonhard Bernold: “Engineering of lunar bases”

February 17, 2008April 26, 2016 by Ian O'Neill

What Would Happen if a Small Black Hole Hit the Earth?

We can all guess what would happen should a massive black hole drift into our solar system… there wouldn’t be much left once the intense gravitational pull consumes the planets and starts sucking away atÂ our Sun. But what if the black hole is small, perhaps aÂ left over remnantÂ from the Big Bang, passing unnoticed through our neighborhood, having no observable impact on local space? What if this small singularity falls in the path of Earths orbit and hits our planet? This strange event has been pondered by theoretical physicists, understanding how a small black hole could be detected as it punches a neat hole though the Earth…

Primordial black holes (PBHs)Â are a predicted product of the Big Bang. Due to the massive energyÂ generated at the beginning ofÂ our Universe,Â countless black holes are thought to have been created. However, small black holes are not expected to live very long. As black holes are theorized to radiate energy, they will also lose mass (according to Stephen Hawking’s theory, Hawking Radiation), smallÂ black holes will therefore fizz out of existence very rapidly. In a well known 1975 publication by Hawking, he estimates the minimum size a black hole must be to survive until present day. The PBH would have to be at least 10¹²kg (that’s 1,000,000,000,000 kg) in mass when it is created. 10¹²kg is actually quite small in cosmic standards – Earth has a mass of 6Ã—10²⁴kg – so we are talking about the size of a small mountain.

So, picture the scene. The Earth (any planet for that matter) is happily orbiting the Sun. A small primordial black hole just happens to be passing through our solar system, and across Earths orbit. We are all aware of how a rocky body such as a Near Earth Asteroid would affect the Earth if it hit us, but what would happen if a small Near Earth Black Hole hit us? Theoretical physicists from the Budker Institute of Nuclear Physics in Russia, and the INTEGRAL Science Data Center in Switzerland, have been pondering this same question, and in a new paper they calculate how we might observe the event should it happen (just in case we didn’t know we had hit something!).

PBHs falling into stars or planetsÂ haveÂ been thought of before. As previously reviewed in theÂ Universe Today, some observations of the planets and stars could be attributed to small black holes getting trapped inside the gravitational well of the body. This might explain the unusual temperatures observed in Saturn and Jupiter, they are hotter than they should be, the extra heat might be produced by interactions with a PBH hiding inside. If trapped within a star, a PBH might take energy from the nuclear reactions in the core, perhaps bringing on a premature supernova. But what if the PBH is travelling very fast and hits the Earth? This is what this research focuses on.

I’d expect some catastrophic, energetic event as a primordial black hole hits the Earth. After all, it’s a black hole! But the results from this paper are a bit of an anti-climax, but cool all the same.

By calculating where the energy from the collision may come from, the researchers can estimate what effect the collision may have. The two main sources of energy will be from the PBH actually hitting Earth material (kinetic) and from black hole radiation. Assuming we have more likelihood of hitting a micro-black hole (i.e. much, much smaller than a black hole from a collapsed star) originating from the beginning of the Universe, it is going to be tiny. Using Hawking’s 10¹²kg black hole as an example, a black hole of this size will have a radius of 1.5Ã—10^-15 meters… that’s approximately the size of a proton!

This may be one tiny black hole, but it packs quite a punch. But is it measurable? PBHs are theorized to zip straight through matter as if it wasn’t there, but it will leave a mark. As the tiny entity flies through the Earth at a supersonic velocity, it will pump out radiation in the form of electrons and positrons. The total energy created by a PBH roughly equals the energy produced by the detonation of one tonne of TNT, but this energy is the total energy it deposits along its path through the Earths diameter, not the energy it produces on impact. So don’t expect a magnificent explosion, we’d be lucky to see a spark as it hits the ground.

Any hopes of detecting such a small black hole impact are slim, as the seismic waves generated would be negligible. In fact, the only evidence of a black hole of this size passing through the planet will be the radiation damage along the microscopic tunnel passing from one side of the Earth to the other. As boldly stated by the Russian/Swiss team:

“It creates a long tube of heavily radiative damaged material, which should stay recognizable for geological time.” – Khriplovich, Pomeransky, Produit and Ruban, from the paper: “Can one detect passage of small black hole through the Earth?“

As this research focuses on a tiny, primordialÂ black hole,Â itÂ would be interesting to investigate the effects of a larger black hole would haveÂ on impact – perhaps one with the mass of the Earth andÂ the radius ofÂ a golf ball…?

Source paper: arXiv

February 16, 2008December 26, 2015 by Ian O'Neill

Finding “Tightens the Noose on the Possibility of Life” on Mars

So far, the Mars Exploration Rover (MER) Mission has turned up very little evidence that there is, or was, life on the Red Planet. Even more bad news is on the way from data sent back from NASA rovers Opportunity and Spirit – it would seem that the planetÂ was “too salty” for even the toughest organisms on Earth to survive. It would appear, from new results presented at the American Association for the Advancement of Science (AAAS) in Boston, that although Mars had abundant supplies of water in the past, its oceans would have been too acidic, withÂ poisonous concentrations of minerals. Even when conditions were best on the surface, the very toughest microbes will have found it difficult…

The NASA MER mission has been a resounding success. Both Opportunity and Sprit have operated on Mars longer than any mission scientist would have dreamed. So far, both rovers have been trundling around on the planet forÂ nearly four years, and have carried out some exciting science, analysing the Martian regolith and rocks, observing atmospherics and geology, not forgetting the spectacular panoramic photography… but they have yet to find any compelling evidence for life. Even after the excitement of Spirits big discovery back in Decemeber, the hunt for Martian life remains inconclusive.

Now, it seems, there’s another blow for life on Mars – it’s too salty. It’s been known for a long time that Mars once had large quantities of water, giving hope that life once thrived on the planet. But these new findings suggest the water may have been too rich in minerals, making it very difficult for life (as we know it) to survive.

“It was really salty – in fact, it was salty enough that only a handful of known terrestrial organisms would have a ghost of a chance of surviving there when conditions were at their best.” – Dr Andrew Knoll, a biologist at Harvard University, speaking at the AAAS meeting.

This news comes from Opportunity, currently working in Duck Bay (an alcove attached to Victoria Crater, pictured left) and these new results come from rock analysis in the region. Although this may be discouraging for scientists trying to find life on Mars, this is by no means the final straw. The Phoenix Mission is currently en-route to Mars and one of its mission objectives is to carry out advanced analysis for Martian life. Phoenix lands on May 25 of this year to hunt for life in the frozen North Pole. Also, the Mars Science Laboratory (MSL) is expected for launch in 2009 and will continue the hunt for organic compounds in the Martian regolith.

Source: BBC

February 14, 2008December 26, 2015 by Ian O'Neill

Human Damage to World Oceans Mapped, 40% “Strongly Impacted”

If we needed any more proof that we as a race are damaging the worlds oceans, for the first time, our impact has been mapped by new study to be published in Science. It makes for uncomfortable viewing. Taking 17 known types of human impact on marine ecosystems, this new research suggests that only 4% of the oceans are relatively untouched, whilst 40% are strongly impacted by human activity. The mostÂ impacted marine ecosystems include the North Sea, the South and East China Seas, the Caribbean, the Mediterranean, the Red Sea, the Gulf, the Bering Sea, the East coast of North America and in much of the western Pacific.

The new, high-resolution map of predominantly yellow regions and red dots could be mistaken for a global temperature map. However, this map is the first of its kind, mapping damaging human activity in the worlds oceans. At first glance it is obvious that most of the oceans have been affected in some way by the continued onslaught of human activity, with only the Polar Regions holding some of the most pristine and untouched seas. These are about the only portions of the map where the reach of human activity cannot grasp, but as global warming increases, the protective ice-sheets are likely to reveal more sea for humankind to exploit.

This new research was released today at the AAAS Annual Meeting and will be published in the February 15th issue of Science. The scientists behind this study are attending a special three day seminar on “Managing Threats to Marine Ecosystems”. Although this work highlights the concerns about damage to our oceans, it may also aid future efforts to preserve areas of low human impact and will help us identify the worst affected regions.

“Whether one is interested in protecting ocean wilderness, assessing which human activities have the greatest impact, or prioritizing which ecosystem types need management intervention, our results provide a strong framework for doing so.” – Kimberly Selkoe of the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara, CA and the University of Hawaii.

The map was created by dividing the Earths oceans into a grid of 1kmÃ—1km squares. The 17 contributing human factors were identifiedÂ (including fishing, coastal development, fertiliser runoff and pollution from shipping traffic) and the extent at which each grid-point was influenced by each contributing factor was calculated. An “impact score” was then allocated at each location to rate how 20 different types of ecosystem are affected by each factor. It was found that an astonishingly high 41% of the oceans had medium-high to high impact ratings. 0.5% had very high impact ratings, representing 2.2 million square km (850,000 square miles).

Although these results may seem grim, it is the first chance scientists have had to evaluate the worst affected oceans, and many appear upbeat about managing the oceans better,Â preserving what is left of our pristine seas.

“Our results show that when these and other individual impacts are summed up, the big picture looks much worse than I imagine most people expected. It was certainly a surprise to me. […] With targeted efforts to protect the chunks of the ocean that remain relatively pristine, we have a good chance of preserving these areas in good condition.” – Ben Halpern, assistant research scientist at the University of California, Santa Barbara, research leader. “

Source: AAAS, Guardian Online

February 14, 2008December 26, 2015 by Ian O'Neill

US Planning to Shoot Down Dead Spy Satellite

The US Navy is planning to shoot down a dead spy satellite that broke down shortly after it was launched in December 2006. Not only are there fears that the large satellite could survive re-entry through the Earth’s atmosphere causing damage and perhaps fatalities, the satellite is also carrying the poisonous hydrazine propellant that could be a health risk if inhaled. Therefore plans are afoot to destroy the craft in orbit rather than letting it fall to Earth some time late February or early March.

This has been a frustrating time for the US military. As previously reported on the Universe Today, one of their most advanced spy satellite systems broke down soon after it was launched into space, leaving mission controllers in the dark as to where the satellite was going. This is bad enough, but if the satellite fell to Earth, it could reveal potentially sensitive secrets about the US spying technology. And not forgetting the potential risk of damage or death should the chunk of high-tech scrap fall to Earth… the US military is now planning to take action rather than leaving it up to gravity to decide where the satellite will crash.

Officially, the reason for the planned shooting down of the craft is not to destroy top secret technology (as most of the sensitive material is likely to burn up) but to prevent deadly fumes from being produced from the propellants the craft has in abundance onboard (after all, it didn’t have much of a chance to use any of its fuel). This is an opportunity for the US Navy to use one of its ballistic missile launchers onboard one of its support vessels. The Arleigh Burke class destroyer, USS Decatur (pictured) underwent ballistic missile launch tests last year, built to intercept incoming missiles high in the atmosphere. The satellite, presumed to be in a low Earth orbit, may be reached by such a missile defence system.

The area affected by the hydrazine should the fuel tanks survive re-entry would cover two football pitches, and if inhaled, would have similar effects to chlorine or ammonia – causing a burning sensation in the lungs. If too much is breathed in, it could prove deadly. A US military general stated that should the plan go ahead, they will take one missile shot and then assess whether a second would be required during a two day window. He also added that the Space Shuttle Atlantis will have landed before any such interception attempt is made.

February 13, 2008December 26, 2015 by Ian O'Neill

Real-Time Solar Storm Warning Now Operational, Protecting Astronauts and Satellites

Highly energetic solar particles are generated by solar flares and can be harmful to astronauts and sensitive satellite circuits. Solar flares are most likely to occur during periods of heightened solar activity (i.e. during solar maximum at the peak of the 11 year solar cycle), and future manned missions will need to be highly cautious not to be unprotected in space at these times. Many attempts are underway at forecasting solar activity so “solar storms” can be predicted, but a form of early warning system is required to allow time for astronauts to seek cover and satellites put in a low-power state. Now, using the Solar and Heliospheric Observatory (SOHO), scientists are testing a new method of detecting high energy solar ions, in real-time.

Using SOHO as an early warning system isn’t a new idea. Ideally positioned at the Sun-Earth First Lagrange Point (L₁), SOHO orbits its little island of gravitational stability in direct line of sight to the Sun, 1.5 million km from the Earth. Anything that comes from the Sun will have to pass through the L₁ point, firing through any robotic observers positioned there.

SOHO is in good company. Also positioned at the L₁point is the Advanced Composition Explorer (ACE)Â that takes measurements of the solar wind as solar particles continue their way toward the Earth. However, the advanced instrumentation on SOHO allows it to detect very fast electrons (near-relativistic) as they are generated by the Sun. The Comprehensive Suprathermal and Energetic Particle Analyzer (COSTEP) instrument onboard SOHO has provided data about highly energetic particles since 1995, but it’s never been in real-time. Now, using a new technique, solar scientists are able to receive particle data with an hour warning of an impending storm of energetic ions.

When a flare explodes via magnetic interactions on the Sun, electrons and ions are accelerated and burst into space. Travelling at high speed, electrons reach SOHO much quicker than the heavier ions. What’s more, the relativistic electrons are harmless, so they provide an ideal, safe, indicator that the damaging ions are following behind.

The forecasting method was developed eight months agoÂ by Dr Arik Posner (Southwest Research Institute, USA) and scientists from the University of Kiel (Germany), NASA’s Goddard Space Flight Center (USA) and the University of Turku (Finland). Oliver Rother from the University of Kiel has seen the potential for the new real-time system and explains, “We were so excited by Posner’s project that we immediately teamed up and developed new software that displays the data and can give a warning three minutes after taking the measurements 1.5 million km away.”

This is obviously good news for any astronaut in Earth orbit, but generally they are protected from intermediate solar storms as they are within the protective shield of the magnetosphere. This system will be most useful for the future colonists of the Moon and any long-haul manned missions to Mars. It may only be an hours warning, but that hour could make allÂ the difference between mission success and mission failure.

Source: SpaceRef.com