Reports of Strange Sounds from the Sky

There appears to be an upsurge recently in reports of strange sounds coming from the skies ~ sometimes a low rumble, other times a whine, thump or a melody. Because the nature of the sounds vary so much, researchers are having difficulties pinpointing their origins.

According to Discovery News:

There are a few things to keep in mind about these strange, ambient sounds; for one thing, there is virtually no place on the planet where noise pollution is not a problem. We live in a constant sea of background noise, most of it unnoticed until we start paying attention to all the sounds and focusing on them. 

Sources of indoor sounds are nearly endless, from faintly ticking clocks to air-conditioning to bubbling aerators in fish tanks. Outside the problem is far worse, with noise generated by countless sources including traffic; airplanes (seen and unseen); radios; lawnmowers and snowblowers; trains; highways; and high-tension lines. 

Then there are the many industrial sources of noise and vibrations, including power plants and any factories with large machines such as auto assembly plants and printing presses.

For example, a flood of reports concerning a rumbling midnight sound in Malaysia eventually was determined to be caused by machinery tests a palm-oil company was performing each night.

Click here for the complete article.

'Spacequakes" Disrupting Earth's Magnetic Field

Spacequakes contribute to auroras in the night sky.

Called “spacequakes,” bursts of plasma flying off of the sun are disrupting Earth’s magnetic field with the strength of a sizeable earthquake, according to new scientific evidence.

“The total energy in a spacequake can rival that of a magnitude 5 or 6 earthquake,” Evgeny Panov of the Space Research Institute in Austria tells the Christian Science Monitor. He is first author of a paper reporting the results of a study on spacequakes in the April 2010 issue of Geophysical Research Letters.

NASA’s THEMIS space probes discovered the precursors of spacequakes in 2007. According to the Monitor: 

The action begins in Earth's magnetic tail, which is stretched out like a windsock by the million-miles-per-hour solar wind. Sometimes the tail can become so stretched and tension-filled, it snaps back like an over-torqued rubber band. Solar wind plasma trapped in the tail hurtles toward Earth. 

On more than one occasion, the five THEMIS spacecraft were in the line of fire when these “plasma jets” swept by. Clearly, the jets were going to hit Earth. But what would happen then? The fleet moved closer to the planet to find out. 

“Now we know," said THEMIS project scientist David Sibeck of NASA's Goddard Space Flight Center. “Plasma jets trigger spacequakes.”

Research shows that the plasma jets crash into Earth’s geomagnetic field some 18,600 miles above the equator. The impact sets off a rebounding process, in which the incoming plasma actually bounces up and down on the reverberating magnetic field. The first bounce is a big one, followed by bounces of decreasing amplitude as energy is dissipated in the carpet.

Click here for the complete article.

Outlying Moons Suitable for Exploration

Depiction of surface of Saturn moon Titan.

NASA’s leading candidates for extraterrestrial life are now Saturn’s moons Titan and Enceladus or perhaps Jupiter’s moons Europa and Ganymede. Scientists are weighing the possibilities in anticipation of picking a destination for a $4 billion space mission set for around 2020.

According to the BBC, the potential Saturn mission would follow up the remarkable discoveries made by the Nasa/Esa Cassini-Huygens mission which continues to operate at the ringed planet. Cassini has sent back data that indicates Titan is akin to a primitive ~ albeit frozen ~ Earth. It has a thick atmosphere and is rich in organic (carbon-rich) molecules.

But Nature News says the arguments for exploring Jupiter’s moons are just as compelling. In 1995, the Galileo probe began an 8-year tour of Jupiter’s system, during which it snapped the first close-ups of Europa’s scarred surface. Analysis of a magnetic anomaly soon revealed the moon’s most astonishing feature: that eggshell of ice is thought to enclose a warm, salty ocean. Scientists immediately clamoured to return.

Click here for the Discover magazine article.

NASA Finds Huge Breach in Magnetic Field

Artist’s concept of a THEMIS probe exploring the space around Earth.

NASA this week reported that spacecraft have discovered a breach in Earth's magnetic field 10 times larger than anything previously thought to exist. Solar wind can flow in through the opening to "load up" the magnetosphere for powerful geomagnetic storms.

But the breach itself is not the biggest surprise, NASA says. Researchers are even more amazed at the strange and unexpected way it forms, overturning long-held ideas of space physics.

"At first I didn't believe it," says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. "This finding fundamentally alters our understanding of the solar wind-magnetosphere interaction."

Solar-Wind Protection Lessened

The magnetosphere is a bubble of magnetism that surrounds Earth and protects us from solar wind. Exploring the bubble is a key goal of the THEMIS mission, launched in February 2007. The big discovery came on June 3, 2007, when the five probes serendipitously flew through the breach just as it was opening.

"The opening was huge—four times wider than Earth itself," says Wenhui Li, a space physicist at the University of New Hampshire who has been analyzing the data.

The event began with little warning when a gentle gust of solar wind delivered a bundle of magnetic fields from the Sun to Earth. Like an octopus wrapping its tentacles around a big clam, solar magnetic fields draped themselves around the magnetosphere and cracked it open. The cracking was accomplished by means of a process called "magnetic reconnection."

Breach Unexpectedly Large

High above Earth's poles, solar and terrestrial magnetic fields linked up to form conduits for solar wind. Conduits over the Arctic and Antarctic quickly expanded. Within minutes they overlapped over Earth's equator to create the biggest magnetic breach ever recorded by Earth-orbiting spacecraft.

The size of the breach took researchers by surprise. "We've seen things like this before, but never on such a large scale," says physicist Jimmy Raeder, "The entire day-side of the magnetosphere was open to the solar wind."

Implications Are ‘Seismic’

The circumstances were even more surprising. Space physicists have long believed that holes in Earth's magnetosphere open only in response to solar magnetic fields that point south. The great breach of June 2007, however, opened in response to a solar magnetic field that pointed north.

"To the lay person, this may sound like a quibble, but to a space physicist, it is almost seismic," says Sibeck. "When I tell my colleagues, most react with skepticism, as if I'm trying to convince them that the sun rises in the west."

Click here for the complete NASA press release.

Mysterious High-Energy Rays Bombarding Earth

Drawing illustrating air showers from high-energy cosmic rays, which were unexpectedly discovered in 1912.

Researchers have discovered a puzzling surplus of high-energy electrons bombarding Earth from space. The source is unknown, but it must be close to the solar system and could be made of dark matter.

"This is a big discovery," says John Wefel of Louisiana State University. "It's the first time we've seen a discrete source of accelerated cosmic rays standing out from the general galactic background."

Galactic cosmic rays are subatomic particles accelerated to almost light speed by distant supernova explosions and other violent events, according to an explanation from NASA. They swarm through the Milky Way, forming a haze of high-energy particles that enter the solar system from all directions.

Wefel likens the bombardment to driving down a freeway among family sedans, mini-vans and trucks—when suddenly a bunch of Lamborghinis bursts through the normal traffic. "You don't expect to see so many race cars on the road—or so many high-energy electrons in the mix of cosmic rays," he says. Seventy electrons may not sound like a great number, but like seventy Lamborghinis on the freeway, it's a significant surplus.

Click here for the complete explanation from NASA.

Astronomers Perplexed by "Dark Flow"

NASA photo of galaxy cluster 1E 0657-56 lying 3.8 billion light-years away. It's one of hundreds that appear to be carried along by a mysterious cosmic flow.

Here’s today’s second post sounding like something from Sci-Fi: This time it’s strange patches of dark matter moving through the universe, at high speeds and in a uniform direction, with nothing in the observable universe propelling them.

Astronomers are calling the phenomenon “dark flow.” According to an article on Space.com:

Scientists discovered the flow by studying some of the largest structures in the cosmos: giant clusters of galaxies. These clusters are conglomerations of about a thousand galaxies, as well as very hot gas which emits X-rays. By observing the interaction of the X-rays with the cosmic microwave background (CMB), which is leftover radiation from the Big Bang, scientists can study the movement of clusters.

The X-rays scatter photons in the CMB, shifting its temperature in an effect known as the kinematic Sunyaev-Zel'dovich (SZ) effect. This effect had not been observed as a result of galaxy clusters before, but a team of researchers led by Alexander Kashlinsky, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md., found it when they studied a huge catalogue of 700 clusters, reaching out up to 6 billion light-years, or half the universe away. They compared this catalogue to the map of the CMB taken by NASA's Wilkinson Microwave Anisotropy Probe (WMAP) satellite.

They discovered that the clusters were moving nearly 2 million mph toward a region in the sky between the constellations of Centaurus and Vela. This motion is different from the outward expansion of the universe (which is accelerated by the force called dark energy).

"We found a very significant velocity, and furthermore, this velocity does not decrease with distance, as far as we can measure," Kashlinsky told SPACE.com. "The matter in the observable universe just cannot produce the flow we measure."

The scientists deduced that whatever is driving the movements of the clusters must lie beyond the known universe.

Click here for the complete Space.com article.

Solar Wind Drop Means More Cosmic Rays

NASA photo showing charged particles bursting from the sun’s surface. Temperatures are 1.8 million degrees Fahrenheit. The blue color enables the human eye to perceive the solar activity’s ultraviolet light.

It sounds like the plot of a sci-fi movie, but it could be serious: The sun’s solar wind is now blowing with less intensity than at any time since the mid-20th Century, exposing Earth to more cosmic rays.

According to an article today on Discovery News:

The sun is presently at the lowest point in its 11-year cycle of sunspot activity, but it's also 20 percent cooler and less windy than the last solar minimum in 1994-95, explained Karine Issautier, the Ulysses radio wave lead investigator at the Observatoire de Paris, Meudon, France. In other words, the sun is showing signs of other, much longer cycles which also affect its power output.

The sun is also hitting an all-time low for its wind speed and pressure, blowing at 25 percent less than at the last solar minimum, Southwest Research Institute's David McComas told Discovery News.

The bubble of charged solar particles that fills the solar system is shrinking, exposing Earth and other planets to the onslaught of needling galactic cosmic rays normally held at bay by the solar wind. Inside Earth's magnetic field the main effect of the cooler, less windy sun is the cooling and lowering of the outermost part of the atmosphere. 

Click here for the Discovery News article.