Tag: BBC news

Birth of the Nibiru Legend? Astronomers Say Alien Star System Buzzed Our Sun

Scholz's star - shown in this artist's impression - is currently 20 light-years away. But it once came much closerExcerpt from bbc.comAn alien star passed through our Solar System just 70,000 years ago, astronomers have discovered.  No othe...

View Article Here   Read More

Planck telescope puts new datestamp on first stars


Polarisation of the sky
Planck has mapped the delicate polarisation of the CMB across the entire sky



Excerpt from bbc.com

Scientists working on Europe's Planck satellite say the first stars lit up the Universe later than previously thought.

The team has made the most precise map of the "oldest light" in the cosmos.

Earlier observations of this radiation had suggested the first generation of stars were bursting into life by about 420 million years after the Big Bang.

Planck's data indicates this great ignition was well established by some 560 million years after it all began.

"This difference of 140 million years might not seem that significant in the context of the 13.8-billion-year history of the cosmos, but proportionately it's actually a very big change in our understanding of how certain key events progressed at the earliest epochs," said Prof George Efstathiou, one of the leaders of the Planck Science Collaboration.

Subtle signal

The assessment is based on studies of the "afterglow" of the Big Bang, the ancient light called the Cosmic Microwave Background (CMB), which still washes over the Earth today.
Prof George Efstathiou: "We don't need more complicated explanations"

The European Space Agency's (Esa) Planck satellite mapped this "fossil" between 2009 and 2013.

It contains a wealth of information about early conditions in the Universe, and can even be used to work out its age, shape and do an inventory of its contents.

Scientists can also probe it for very subtle "distortions" that tell them about any interactions the CMB has had on its way to us.

Forging elements

One of these would have been imprinted when the infant cosmos underwent a major environmental change known as re-ionisation.

Prof Richard McMahon: "The two sides of the bridge now join"
It is when the cooling neutral hydrogen gas that dominated the Universe in the aftermath of the Big Bang was then re-energised by the ignition of the first stars.

These hot giants would have burnt brilliant but brief lives, producing the very first heavy elements. But they would also have "fried" the neutral gas around them - ripping electrons off the hydrogen protons.

And it is the passage of the CMB through this maze of electrons and protons that would have resulted in it picking up a subtle polarisation.

ImpressionImpression: The first stars would have been unwieldy behemoths that burnt brief but brilliant lives


The Planck team has now analysed this polarisation in fine detail and determined it to have been generated at 560 million years after the Big Bang.

The American satellite WMAP, which operated in the 2000s, made the previous best estimate for the peak of re-ionisation at 420 million years. 

The problem with that number was that it sat at odds with Hubble Space Telescope observations of the early Universe.

Hubble could not find stars and galaxies in sufficient numbers to deliver the scale of environmental change at the time when WMAP suggested it was occurring.

Planck's new timing "effectively solves the conflict," commented Prof Richard McMahon from Cambridge University, UK.

"We had two groups of astronomers who were basically working on different sides of the problem. The Planck people came at it from the Big Bang side, while those of us who work on galaxies came at it from the 'now side'. 

"It's like a bridge being built over a river. The two sides do now join where previously we had a gap," he told BBC News.

That gap had prompted scientists to invoke complicated scenarios to initiate re-ionisation, including the possibility that there might have been an even earlier population of giant stars or energetic black holes. Such solutions are no longer needed.

No-one knows the exact timing of the very first individual stars. All Planck does is tell us when large numbers of these stars had gathered into galaxies of sufficient strength to alter the cosmic environment. 

By definition, this puts the ignition of the "founding stars" well before 560 million years after the Big Bang. Quite how far back in time, though, is uncertain. Perhaps, it was as early as 200 million years. It will be the job of the next generation of observatories like Hubble's successor, the James Webb Space Telescope, to try to find the answer.

JWSTBeing built now: The James Webb telescope will conduct a survey of the first galaxies and their stars
line
The history of the Universe

Graphic of the history of time
  • Planck's CMB studies indicate the Big Bang was 13.8bn years ago
  • The CMB itself can be thought of as the 'afterglow' of the Big Bang
  • It spreads across the cosmos some 380,000 years after the Big Bang
  • This is when the conditions cool to make neutral hydrogen atoms
  • The period before the first stars is often called the 'Dark Ages'
  • When the first stars ignite, they 'fry' the neutral gas around them
  • These giants also forge the first heavy elements in big explosions
  • 'First Light', or 'Cosmic Renaissance', is a key epoch in history
line

The new Planck result is contained in a raft of new papers just posted on the Esa website. 

These papers accompany the latest data release from the satellite that can now be used by the wider scientific community, not just collaboration members.
Dr Andrew Jaffe: "The simplest models for inflation are ruled out"
Two years ago, the data dump largely concerned interpretations of the CMB based on its temperature profile. It is the CMB's polarisation features that take centre-stage this time.
It was hoped that Planck might find direct evidence in the CMB's polarisation for inflation - the super-rapid expansion of space thought to have occurred just fractions of a second after the Big Bang. This has not been possible. But all the Planck data - temperature and polarisation information - is consistent with that theory, and the precision measurements mean new, tighter constraints have been put on the likely scale of the inflation signal, which other experiments continue to chase.
What is clear from the Planck investigation is that the simplest models for how the super-rapid expansion might have worked are probably no longer tenable, suggesting some exotic physics will eventually be needed to explain it.
"We're now being pushed into a parameter space we didn't expect to be in," said collaboration scientist Dr Andrew Jaffe from Imperial College, UK. "That's OK. We like interesting physics; that's why we're physicists, so there's no problem with that. It's just we had this naïve expectation that the simplest answer would be right, and sometimes it just isn't."

View Article Here   Read More

Meteorite is ‘hard drive’ from space ~ Researchers decode ancient recordings from asteroid ~ BBC


Pallasite meteorite
The Esquel meteorite consists of gem-quality crystals embedded in metal.



Excert from bbc.com

Researchers have decoded ancient recordings from fragments of an asteroid dating back billions of years to the start of the Solar System. 

They found tiny "space magnets" in meteorites which retain a memory of the birth and death of the asteroid's core.
Like the data recorded on the surface of a computer hard drive, the magnetic signals written in the space rock reveal how Earth's own metallic core and magnetic field may one day die.

The work appears in Nature journal.

Using a giant X-ray microscope, called a synchrotron, the team was able to read the signals that formed more than four-and-a-half billion years ago, soon after the birth of the Solar System.

Start Quote

It's like a cosmic archaeological mission”
Dr James Bryson University of Cambridge
The meteorites are pieces of a parent asteroid that originally came from asteroid belt, between Mars and Jupiter.
They represents the left-over fragments of a planet that failed to form. The magnetic recording within it traps a signal of the precise moments when an iron-rich core formed in the asteroid as well as when it froze, killing its magnetic field.
The new picture of metallic core solidification in the asteroid provide clues about the magnetic field and iron-rich core of Earth.
Core values "Ideas about how the Earth's core evolved through [our planet's] history are really changing at the moment," lead researcher Dr Richard Harrison, from the University of Cambridge, told BBC News.
"We believe that Earth's magnetic field is linked to core solidification. Earth's solid inner core may have started to form at very interesting time in terms of the evolution of life on Earth.
"By studying an asteroid we get to see this in fast forward. We can see the start of core solidification in the magnetic records as well as its end, and start to think about how these processes work on Earth."

Magnetic fieldThe Earth's magnetic field will likely die off when the core completely freezes
The meteorites studied by the team originally fell to Earth in Argentina, and are composed of gem-quality crystals enclosed in a metallic matrix of iron and nickel. 

Tiny particles, smaller than one thousandth the width of a human hair, trapped within the metal have retained the magnetic signature of the parent asteroid from its birth in the early Solar System.

"We're taking ancient magnetic field measurements in nano-scale materials to the highest ever resolution in order to piece together the magnetic history of asteroids - it's like a cosmic archaeological mission," said Dr James Bryson, the paper's lead author. 

"Since asteroids are much smaller than Earth, they cooled much more quickly, so these processes occur on a shorter timescales, enabling us to study the whole process of core solidification."

Prof Wyn William, from the University of Edinburgh, who was not involved in the study, commented: "To be able to get a time stamp on these recordings, to get a cooling rate and the time of solidification, is fantastic. It's a very nice piece of work."

The key to the long-lived stability of the recording is the atomic-scale structure of the iron-nickel particles that grew slowly in the asteroid core and survived in the meteorites. 

Making a final comment on the results, Dr Harrison said: "In our meteorites we've been able to capture both the beginning and end of core freezing, which will help us understand how these processes affected the Earth in the past and provide a possible glimpse of what might happen in the future." 

View Article Here   Read More

Age of stars can now be pinned to their spin

Excerpt from bbc.comAstronomers have proved that they can accurately tell the age of a star from how fast it is spinning. We know that stars slow down over time, but until recently there was little data to support exact calculations. For ...

View Article Here   Read More

Comet landing: Organic extraterrestrial molecules detected by Philae lander

The Philae lander has detected organic molecules on the surface of its comet, scientists have confirmed.Excerpt from bbc.com By Paul Rincon Science editor, BBC News website Carbon-containing "organics" are the basis of life on Earth and may ...

View Article Here   Read More

Is this the origins of the Anunnaki story? ~ Neanderthals & humans first mated 50,000 years ago, DNA reveals


Early European
Universal human: This reconstruction is of a different modern human from Romania 43,000 years ago. But it gives some clues to what the Siberian man may have looked like. This population was not long out of Africa and genetically midway between Europeans and Asians
Excerpt from bbc.com
The genome sequence from a thigh bone found in Siberia shows the first episode of mixing occurred between 50,000 and 60,000 years ago.

The male hunter is one of the earliest modern humans discovered in Eurasia.

The study in Nature journal also supports the finding that our species emerged from Africa some 60,000 years ago, before spreading around the world.

The analysis raises the possibility that the human line first emerged millions of years earlier than current estimates.

"We seem to have caught evolution red handed”
Prof Svante Paabo Max-Plack Institute
The work of Prof Svante Paabo, from the Max Planck Institute in Leipzig, Germany, is rewriting the story of humanity. Prof Paabo and his colleagues have pioneered methods to extract DNA from ancient human remains and read its genetic code. From this sequence, Prof Paabo has been able to decipher an increasingly detailed story of modern humans as they spread across the globe.

"The amazing thing is that we have a good genome of a 45,000 year old person who was close to the ancestor of all present-day humans outside Africa," Prof Paabo told BBC News. 

Prof Paabo has analysed DNA from part of a leg bone of a man that lived in Western Siberia around 45,000 years ago. This is a key moment at the cross roads of the world, when modern humans were on the cusp of an expansion into Europe and Asia.


Thigh bone

Prof Paabo Svante has unlocked the secrets contained in this femur from one of the earliest humans discovered out of Africa.
The key finding was that the man had large, unshuffled chunks of DNA from a now extinct species of human, Neanderthals who evolved outside of Africa. 

"Our analysis shows that modern humans had already interbred with Neanderthals then and we can determine when that first happened much more precisely than we could before." 

Prof Paabo and his team published research in 2010 which showed that all non-African humans today have Neanderthal DNA. But that genetic material has been broken into much smaller chunks over the generations. 

By extrapolating the size of DNA chunks backwards, Prof Paabo and his colleagues were able to calculate when the first interbreeding with Neanderthals occurred. His study shows that it was between 50,000 and 60,000 years ago.

According to Prof Chris Stringer of the Natural History Museum in London, this early interbreeding might indicate when the ancestors of people living outside of Africa today made their first steps out of the continent in which our species evolved more than 150,000 years ago.

Prof Stringer was among those who believed that the first exit by modern humans from Africa that give rise to people outside of Africa today might have happened earlier, possibly 100,000 years ago. The evidence from Prof Paabo's research is persuading him that it was now much later.


River Irtysh

Crossroads for humanity: the river Irtysh in Western Siberia where the bone was found. 


Prof Paabo also compared the DNA of the man living 45,000 years ago with those living today. He found that the man was genetically midway between Europeans and Asians - indicating he lived close to the time before our species separated into different racial groups.

Prof Paabo was also able to estimate the rate at which human DNA has changed or mutated over the millennia. He found that it was slower than the rate suggested by fossil evidence and similar to what has been observed in families. 

"We have caught evolution red handed!" Prof Paabo said gleefully.
This raises the possibility that the very first species of the human line separated from apes 10 or 11 million years ago - rather than the five or six million years ago that genetic evidence had previously suggested. 

But he stressed in his research paper that much more analysis was needed before re-dating the emergence of the human line.

"We caution that (mutation) rates may have changed over time and may differ between human populations," he said.

View Article Here   Read More

A Compilation of articles about stopping whaling

{mainvote}

Sea Shepherd Returns for a Fourth Season of Whale Wars to Put an End to Antarctic Whaling

Animal Planet's Emmy Award-nominated docu-reality series Whale Wars returns for a fourth season beginning Friday, June 3, at 9 PM E/P wi...

View Article Here   Read More

Cell phones as bad as x-rays

{mainvote}

Would you allow 1600 chest x-rays for yourself or your child?

Some scientists say that’s what 24 hours of cell phone use amounts to. Here’s visual proof.

Slide one (top left) shows a normal healthy cell under ...

View Article Here   Read More




Gaia-Cosmic Disclosure S1E1 LB728x90

Creative Commons License
This work is licensed under a
Creative Commons Attribution 4.0
International License
,
unless otherwise marked.

Terms of Use | Privacy Policy

Member of The Internet Defense League




Up ↑