Listening to the early universe just got harder. A team led by Alan Kogut of NASA's Goddard Space Flight Center in Greenbelt, Md., today announced the discovery of cosmic radio noise that booms six times louder than expected.

The finding comes from a balloon-borne instrument named ARCADE, which stands for the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission. In July 2006, the instrument launched from NASA's Columbia Scientific Balloon Facility in Palestine, Texas, and flew to an altitude of 120,000 feet, where the atmosphere thins into the vacuum of space.

ARCADE's mission was to search the sky for heat from the first generation of stars. Instead, it found a cosmic puzzle.

"The universe really threw us a curve," Kogut says. "Instead of the faint signal we hoped to find, here was this booming noise six times louder than anyone had predicted." Detailed analysis ruled out an origin from primordial stars or from known radio sources, including gas in the outermost halo of our own galaxy. The source of this cosmic radio background remains a mystery.

Many objects in the universe emit radio waves. In 1931, American physicist Karl Jansky first detected radio static from our own Milky Way galaxy. Similar emission from other galaxies creates a background hiss of radio noise.

The problem, notes team member Dale Fixsen of the University of Maryland at College Park, is that there don't appear to be enough radio galaxies to account for the signal ARCADE detected. "You'd have to pack them into the universe like sardines," he says. "There wouldn't be any space left between one galaxy and the next."

The sought-for signal from the earliest stars remains hidden behind the newly detected cosmic radio background. This noise complicates efforts to detect the very first stars, which are thought to have formed about 13 billion years ago -- not long, in cosmic terms, after the Big Bang. Nevertheless, this cosmic static may provide important clues to the development of galaxies when the universe was less than half its present age. Unlocking its origins should provide new insight into the development of radio sources in the early universe. 

"This is what makes science so exciting," says Michael Seiffert, a team member at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "You start out on a path to measure something -- in this case, the heat from the very first stars -- but run into something else entirely, something unexplained."

Seiffert and Kogut announced the findings today at the 213th meeting of the American Astronomical Society in Long Beach, Calif. Four papers describing ARCADE's results have been submitted to The Astrophysical Journal.

ARCADE is the first instrument to measure the radio sky with enough precision to detect this mysterious signal. To enhance the sensitivity of ARCADE's radio receivers, they were immersed in more than 500 gallons of ultra-cold liquid helium. The instrument's operating temperature was just 2.7 degrees above absolute zero.

This is the same temperature as the cosmic microwave background (CMB) radiation, the remnant heat of the Big Bang that was itself discovered as cosmic radio noise in 1965. "If ARCADE is the same temperature as the microwave background, then the instrument's heat cannot contaminate the cosmic signal," Kogut explains.

The NASA-funded project includes scientists and engineers from NASA's Goddard Space Flight Center in Greenbelt, Md.; the Jet Propulsion Laboratory in Pasadena, Calif.; the University of California at Santa Barbara; the University of Maryland; and Brazil's National Institute for Space Research. More than a dozen high school and undergraduate students participated in the payload's development.

The balloon flight was conducted under the auspices of the Balloon Program Office at Wallops Flight Facility by the staff of the Columbia Scientific Balloon Facility.

One of the most enduring questions is how life could have begun on Earth. Molecules that can make copies of themselves are thought to be crucial to understanding this process as they provide the basis for heritability, a critic More..al characteristic of living systems. Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.

The work was published on Thursday, January 8, 2009, in Science Express, the advanced, online edition of the journal Science.

In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.

For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself. Some tentative steps along this road had previously been taken by the Joyce lab and others, but no one could demonstrate that RNA replication could be self-propagating, that is, result in new copies of RNA that also could copy themselves.
In Vitro Evolution

A few years after Tracey Lincoln arrived at Scripps Research from Jamaica to pursue her Ph.D., she began exploring the RNA-only replication concept along with her advisor, Professor Gerald Joyce, who is also dean of the faculty at Scripps Research. Their work began with a method of forced adaptation known as in vitro evolution. The goal was to take one of the RNA enzymes already developed in the lab that could perform the basic chemistry of replication, and improve it to the point that it could drive efficient, perpetual self-replication.

Lincoln synthesized in the laboratory a large population of variants of the RNA enzyme that would be challenged to do the job, and carried out a test-tube evolution procedure to obtain those variants that were most adept at joining together pieces of RNA.

Ultimately, this process enabled the team to isolate an evolved version of the original enzyme that is a very efficient replicator, something that many research groups, including Joyce's, had struggled for years to obtain. The improved enzyme fulfilled the primary goal of being able to undergo perpetual replication. "It kind of blew me away," says Lincoln.
Immortalizing Molecular Information

The replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other - what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits.

"This is the only case outside biology where molecular information has been immortalized," says Joyce.

Not content to stop there, the researchers generated a variety of enzyme pairs with similar capabilities. They mixed 12 different cross-replicating pairs, together with all of their constituent subunits, and allowed them to compete in a molecular test of survival of the fittest. Most of the time the replicating enzymes would breed true, but on occasion an enzyme would make a mistake by binding one of the subunits from one of the other replicating enzymes. When such "mutations" occurred, the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture. "To me that's actually the biggest result," says Joyce.

The research shows that the system can sustain molecular information, a form of heritability, and give rise to variations of itself in a way akin to Darwinian evolution. So, says Lincoln, "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Knocking on the Door of Life

The group is pursuing potential applications of their discovery in the field of molecular diagnostics, but that work is tied to a research paper currently in review, so the researchers can't yet discuss it.

But the main value of the work, according to Joyce, is at the basic research level. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts." He is quick to point out that, while the self-replicating RNA enzyme systems share certain characteristics of life, they are not themselves a form of life.

The historical origin of life can never be recreated precisely, so without a reliable time machine, one must instead address the related question of whether life could ever be created in a laboratory. This could, of course, shed light on what the beginning of life might have looked like, at least in outline. "We're not trying to play back the tape," says Lincoln of their work, "but it might tell us how you go about starting the process of understanding the emergence of life in the lab."

Joyce says that only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life. "We're knocking on that door," he says, "But of course we haven't achieved that."

The subunits in the enzymes the team constructed each contain many nucleotides, so they are relatively complex and not something that would have been found floating in the primordial ooze. But, while the building blocks likely would have been simpler, the work does finally show that a simpler form of RNA-based life is at least possible, which should drive further research to explore the RNA World theory of life's origins.

The paper is titled "Self-sustained Replication of an RNA Enzyme," and the work was supported by NASA and the National Institutes of Health, and the Skaggs Institute for Chemical Biology.

A recent study has revealed that the Milky Way, the galaxy which we form part of is actually larger, bulkier and spinning a lot faster than what astronomers previously thought. For decades, the Milky Way was considered to be the smaller sister of our neighbouring galaxy Andromeda, but this scenario has changed. By mapping the Milky Way in a more detailed, three-dimensional way, it was found that the galaxy is in fact 15% larger in breadth. More important, it is denser, with 50% more mass, making the galaxy now look like the fraternal twin of Andromeda, rather than its smaller sibling. The Milky way is also spinning faster at its centre, now the figure adjusted to 568,000mph (compared to the previous calculation of 492,000mph). What this means that the doomed collision between the Milky Way and Andromeda will happen even earlier than predicted. But don't worry, we're looking at about 2-3 Billion Years from now. So, no need to panic. I'm pretty sure that nobody reading this article will be there to live the experience.

You can download a high-resolution photo (2700x2700 pixels) from the images section of the site.

One thing that totally fascinates me, and which has slowly become one of my major areas of interest is astrophysics. The grandiosity of the universe is so hard to comprehend, and its complexity and mysteries, all waiting to be discovered, have lured scientists from the dawn of mankind.

As you have probably read in the news today (for those of you, which will definitely read this blog in the future, here's a link to the Article), scientists have now confirmed the existance of a SuperMassive Black hole at the centre of our galaxy - the Milky Way. The most difficult thing to comprehend is to understand the magnitude of this stellar giant at the centre of our galaxy, and what role it has in the stability of the whole stellar system within.

An artist's impression of the centre of our galaxy.

First of all, let us talk about it's mass and dimensions. The latest studies have indicated that the mass of this object is 4 Million Solar Masses (compared to the previous 3.7 Million estimate), with a diameter of 44 Million kilometers. But what do these figures represent? Here is a quick comparison:

• Sun - 333,000 times mass of Earth
  Sagittarius-A - 1.33 Trillion (1,330,000,000,000) times mass of Earth
• Sun - 110 times diamter of Earth
  Sagittarius-A - 3350 times diameter of Earth
• Sun - 5.58 Million (5,580,000) times volume of Earth
  Sagittarius-A - 158 Billion (158,000,000,000) times volume of Earth
• Sun - 0.0597 times density of earth (16.7 times less dense)
  Sagittarius-A - 8.41 times denser than earth

The density is also impressive. A volume of 10cm x 10cm x10cm (1000cc) was to be filled with each of the following, here are the respective weights:

• Water - 1Kg
• Gold - 19.3Kgs
• Osmium (densest element known to man) - 22.61Kgs
• Earth (average) - 6.88Kgs
• Sun (average) - 0.41Kgs
• Sagittarius A (average) - 58Kgs

The impressive density of the black hole, which is higher than any known element or material makes its action on the galaxy even more apparent, but this will be tackled in another blog entry.

Relative positioning of Earth and Sagittarius-A in the Milky Way