Posted on by Nancy Atkinson

How to Escape From a Black Hole

Black Hole surrounded by dust. Credit: ESA / V. Beckmann (NASA-GSFC)

According to Einstein’s theory of general relativity, black holes are regions of space where gravity is so strong that not even light can escape. And in the 1970’s physicist Stephen Hawking asserted that any information sucked inside a black hole would be permanently lost. But now, researchers at Penn State have shown that information can be recovered from black holes.

A fundamental part of quantum physics is that information cannot be lost, so Hawking’s claim has been debated. His idea was generally accepted by physicists until the late 1990s, when many began to doubt the assertion. Even Hawking himself renounced the idea in 2004. Yet no one, until now, has been able to provide a plausible mechanism for how information might escape from a black hole. A team of physicists led by Abhay Ashtekar, say their findings expand space-time beyond its assumed size, providing room for information to reappear.

Ashtekar used an analogy from Alice in Wonderland: “When the Cheshire cat disappears, his grin remains,” he said. “We used to think it was the same way with black holes. Hawking’s analysis suggested that at the end of a black hole’s life, even after it has completely evaporated away, a singularity, or a final edge to space-time, is left behind, and this singularity serves as a sink for unrecoverable information.”

But the Penn State team suggest that singularities do not exist in the real world. “Information only appears to be lost because we have been looking at a restricted part of the true quantum-mechanical space-time,” said Ashtekar. “Once you consider quantum gravity, then space-time becomes much larger and there is room for information to reappear in the distant future on the other side of what was first thought to be the end of space-time.”

According to Ashtekar, space-time is not a continuum as physicists once believed. Instead, it is made up of individual building blocks, just as a piece of fabric, though it appears to be continuous, is made up of individual threads. “Once we realized that the notion of space-time as a continuum is only an approximation of reality, it became clear to us that singularities are merely artifacts of our insistence that space-time should be described as a continuum.”

To conduct their studies, the team used a two-dimensional model of black holes to investigate the quantum nature of real black holes, which exist in four dimensions. That’s because two-dimensional systems are simpler to study mathematically. But because of the close similarities between two-dimensional black holes and spherical four-dimensional black holes, the team believes that this approach is a general mechanism that can be applied in four dimensions. The group now is pursuing methods for directly studying four-dimensional black holes.

The team’s work will be published in the May 20, 2008 issue of the journal Physical Review Letters.

Original News Source: Penn State Press Release

Posted on by Nancy Atkinson

Pole Shift on Europa?

Curved features on Jupiter’s moon Europa may indicate that its poles have wandered by almost 90°, a new study reports. Researchers believe the drastic shift in Europa’s rotational axis was likely a result of the build-up of thick ice at the poles. “A spinning body is most stable with its mass farthest from its spin axis,” says Isamu Matsuyama of the Carnegie Institution’s Department of Terrestrial Magnetism. “On Europa, variations in the thickness of its outer shell caused a mass imbalance, so the rotation axis reoriented to a new stable state” An extreme shift like this also suggests the existence of an internal liquid ocean beneath the icy crust.

The research team, led by Dr. Paul Schenk of the Lunar and Planetary Institute and joined by Matsuyama and Dr. Francis Nimmo of the University of California, Santa Cruz, used images from the Voyager, Galileo, and New Horizons spacecraft to map several large arc-shaped depressions that extend more than 500 kilometers across Europa’s surface. With a radius of about 1500 kilometers, Europa is slightly smaller than the Earth’s moon.

By comparing the pattern of the depressions with fractures that would result from stresses caused by a shift in Europa’s rotational axis, the researchers determined that the axis had shifted by approximately 80°. The previous axis of rotation is now located about 10° from the present equator.

Such a change is called “true polar wander” as opposed to apparent polar wander caused by plate tectonics. There is evidence for true polar wander on Earth, and also on Mars and on Saturn’s moon Enceladus. “Our study adds Europa to this list,” says Matsuyama. “It suggests that planetary bodies might be more prone to reorientation than we thought.”

The study also has implications for liquid water inside Europa. Many scientists believe Europa has an extensive subsurface ocean based on spacecraft photos showing a fractured, icy surface. The ocean beneath the crust would be kept liquid by heat generated by tidal forces from Jupiter’s gravity. The presence of heat and water may make life possible, even though the subsurface ocean is cut off from solar energy.

“The large reorientation on Europa required to explain the circular depressions implies that its outer ice shell is decoupled from the core by a liquid layer,” says Matsuyama. “Therefore, our study provides an independent test for the presence of an interior liquid layer.”

Original News Source: EurekAlert

Posted on by Nancy Atkinson

New NASA Study Links Humans to Changes On Earth

Changes in glaciers. Image courtesy of MSNBC
A new NASA-led study shows human-caused climate change has made an impact on a wide range of Earth’s natural systems, including permafrost thawing, plants blooming earlier across Europe, and lakes declining in productivity in Africa. Researchers at NASA’s Goddard Institute for Space Science and 10 other institutions have linked varying impacts since 1970 with rises in temperatures during that period. “Humans are influencing climate through increasing greenhouse gas emissions,” said Cynthia Rosenzweig, lead author of the study. “The warming is causing impacts on physical and biological systems that are now attributable at the global scale and in North America, Europe, and Asia.”
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Posted on by Nancy Atkinson

The Big Announcement: Chandra, VLA Find Youngest Supernova in Our Galaxy

Astronomers have found the remains of the youngest supernova, or exploded star, in the Milky Way Galaxy. The supernova occurred in 1868, but was hidden behind a thick veil of gas and dust. Using the Very Large Array (VLA) and NASA’s Chandra X-Ray Observatory, which could peer through the veil, astronomers have now found “G1.9+0.3,” the first example of what scientists believe are a “missing population” of young supernova remnants. This is NASA’s long awaited announcement, and astronomers have been searching for over 50 years for this type of young supernova.

From observing supernovae in other galaxies, astronomers estimate that about three such stellar explosions should occur in our Milky Way every century. However, the most recent one known until now occurred around 1680, creating the remnant called Cassiopeia A. The newly-discovered object is the remnant of an explosion only about 140 years ago.

“It’s great to finally track one of them down,” said David Green of the University of Cambridge in the UK, who led the VLA study.

Supernovas mark the violent death of a star, and release tremendous amounts of energy and spew heavy elements such as calcium and iron into interstellar space. This seeds the clouds of gas and dust from which new stars and planets are formed.

The lack of evidence for young supernova remnants in the Milky Way had caused astronomers to wonder if our Galaxy, which appears otherwise normal, differed in some unknown way from others, or if our understanding of the relationship between supernovae and other galactic processes was in error.

Cassiopeia A supernova remnant — from the year 1680.

The astronomers made their discovery by measuring the expansion of the debris from the star’s explosion. They did this by comparing images of G1.9+0.3, made more than two decades apart.

In 1985, astronomers led by Green observed G1.9+0.3 with the VLA and identified it as a supernova remnant. At that time, they estimated its age as between 400 and 1,000 years. It is near the center of our Galaxy, roughly 25,000 light-years from Earth.

In 2007, another team of astronomers, led by Stephen Reynolds of North Carolina State University, observed the object with the Chandra X-Ray Observatory. To their surprise, their image showed
the object to be about 16 percent larger than in the 1985 VLA image.

“This is a huge difference. It means the explosion debris is expanding very quickly, which in turn means the object is much younger than we originally thought,” Reynolds explained.

However, this expansion measurement came from comparing a radio image to an X-ray image.

To make an “apples to apples” comparison, the scientists sought and were quickly granted observing time on the VLA which confirmed the supernova remnant’s rapid expansion.

The object already has provided surprises. The velocities of its explosion debris and extreme energies of its particles are unprecedented. “No other object in the Galaxy has properties like this,” said Reynolds. “Finding G1.9+0.3 is extremely important for learning more about how some stars explode and what happens in the aftermath.”

Original News Sources: Chandra site , National Radio Astronomy Observatory

Posted on by Nancy Atkinson

This Week’s “Where in the Universe?” Challenge

Here’s your image for this week’s “Where in the Universe?” challenge. Take a look at the image and before proceeding to the end of this post, make your guess as to what location in the universe is represented here. It could be anywhere — nothing is off limits for this challenge! Near or distant, far and wide, Universe Today spares no expense when it comes to searching for unique and unusual images to test your visual knowledge of our universe! Give yourself an extra point for guessing (or knowing) the feature shown here, and another point for naming the spacecraft that took this image. Just a couple more ticks on the timer here before revealing the awesome power of this week’s image….

Have you made your guess?

Here’s the answer:

These are cloud vortices found near Alaska, here on Earth. These are called von Karman cloud vortices, named after Theodore von Karman, co-founder of the Jet Propulsion Laboratory. These vortices near the Aleutian Islands were photographed by an Expedition 15 crewmember on the International Space Station. The vortices are created by the wind encountering a barrier such as an island, then changing direction and velocity and forming eddies in the wind and subsequently, in cloud patterns. The image was taken almost a year ago, on May 23, 2007 and the location of the image is at 51.1 degrees north latitude and 178.8 degrees west longitude.

In the cloud image above, the islands disturb the wind flow. As a prevailing wind encounters the island, the disturbance in the flow propagates downstream of the island in the form of a double row of vortices which alternate their direction of rotation. The animation below (courtesy of Cesareo de la Rosa Siqueira at the University of Sao Paulo, Brazil) shows how a von Karman vortex develops behind a cylinder moving through a fluid.

For you camera buffs out there, the image was taken with a Kodak DCS760C Electronic Still Camera.

How’d you do?

Original Source: Gateway to Astronaut Photography of Earth

Posted on by Nancy Atkinson

Vatican Astronomer Says Its OK to Believe in ET

The director of the Vatican observatory said it’s possible that intelligent life exists on other planets. And since aliens would be part of God’s creation, their existence would not contradict the Catholic faith. In an interview with the Vatican newspaper Rev. Jose Gabriel Funes discussed the Big Bang theory, as well as creation and evolution. The interview was originally published in Italian, but a priest from Holland translated the full interview to English and posted it on his website, FatherRoderick.com:

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Posted on by Nancy Atkinson

Scientist Says Texting is More Expensive Than Downloading From Hubble

Does your cell phone bill ever reach astronomical proportions? Maybe you’re doing too much texting. One space scientist has worked out that sending texts via mobile phones works out to be far more expensive than downloading data from the Hubble Space Telescope. Dr. Nigel Bannister from the University of Leicester looked at the cost of obtaining a megabyte of data from Hubble and compared it with the cost of sending a text. His calculations? “The bottom line is texting is at least 4 times more expensive than transmitting data from Hubble, and is likely to be substantially more than that.”

Bannister says, “The maximum size for a text message is 160 characters, which takes 140 bytes because there are only 7 bits per character in the text messaging system, and we assume the average price for a text message is 5 pence (about .10 USD). There are 1,048,576 bytes in a megabyte, so that’s 1 million/140 = 7490 text messages to transmit one megabyte. At 5p each, that’s £374.49 ($734.25 USD) per MB – or about 4.4 times more expensive than the ‘most pessimistic’ estimate for Hubble Space Telescope transmission costs.”

Dr Bannister said NASA provided the numbers of £8.85 ($17.33 USD) per megabyte for the transmission of data from HST to the Earth.

“This doesn’t include the cost of the ground stations and the time of the personnel along the way, but it is an unambiguous number for that part of the process. So that’s £8.85 to get each MB from Hubble, to the first point of contact on the ground, but no further. Hence we need to go a little bit further to estimate exactly how much it costs to transmit data from Hubble to the end user – i.e. to the data archive which scientists can access. This is difficult, so I had to make some conservative assumptions.”

Dr. Bannister estimated the cost of the data from Hubble could vary between £8.85 and £85 per MB- much cheaper than the £374.49 per MB cost of transmitting one MB of text.

Surprised by the results, Bannister said, “Hubble is by no means a cheap mission – but the mobile phone text costs were pretty astronomical!”

Original News Source: Physorg.com

Posted on by Nancy Atkinson

“Tricorder” Checks for Unwanted ISS Microbes

Astronauts on board the space station now have their very own tricorder. While this 21st century version isn’t as versatile as its 24th century counterpart made famous in the Star Trek television series, it will help keep the ISS crew healthy. The real name of this device is LOCAD-PTS, short for Lab-On-a-Chip Application Development Portable Test System. It’s a handheld biological lab specifically designed to detect and identify microbes on space station surfaces.

Wherever there are humans, there are also microbes. Biologists estimate that every human body has at least a trillion hitchhiking microbes, accounting for as much as 2% of a person’s total mass. Most live in harmony with native human cells, but others cause illnesses.

LOCAD can currently detect E. coli, salmonella and fungi. Science@ NASA reports that some fungi can actually decompose electronics, and the ISS is full of electronics essential to maintaining the space station.

LOCAD uses specialized cartridges to find different types of microbes. By the end of the year new cartridges will be sent to the station that can detect staphylococcus and streptococcus.
Eventually scientists hope to have cartridges to detect all kinds of micro-organisms and chemical compounds, so that the device could be used to diagnose what kind of “bug” an astronaut might have if they become ill.

While the Star Trek tricorder could check vital signs and find alien life, LOCAD can be used on lunar missions, long duration stays on other planets, and also here on Earth to keep track of tiny lifeforms.

LOCAD actually looks more like the tricorder from Star Trek: the Next Generation.

Here’s an image of the tricorder from the original Star Trek in the 1960’s.

Original News Source: Science@NASA