If you believe the movies, messages from outer space tend to be carried by UFOs or cute little aliens. But it turns out that secret dispatches from the stars are actually concealed in much less exciting envelopes. Scientists have long suspected that ancient messages lurk within meteorites which crash to earth. Now they have finally proved this theory.
Meteorites are notorious for containing metals, sometimes rare ones, and are even thought to carry the amino acids that began life on this planet, but now researchers have found something even more intriguing – what could be a calendar hidden inside each asteroid that predicts their entire life span – one that dates back billions of years.
Small “space magnets,” or signals emanating from the meteorites act almost like a computer hard drive, maintaining a memory of the core of the asteroid from which they originated. These magnetic fields may even suggest how much longer the Earth itself will be around.
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.
The meteorites 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.
“Observing magnetic fields is one of the few ways we can peek inside a planet,” said Dr Richard Harrison of Cambridge’s Department of Earth Sciences, who led the research.
“It’s long been assumed that metal-rich meteorites have poor magnetic memories, since they are primarily composed of iron, which has a terrible memory – you wouldn’t ever make a hard drive out of iron, for instance. It was thought that the magnetic signals carried by metal-rich meteorites would have been written and rewritten many times during their lifetime, so no-one has ever bothered to study their magnetic properties in any detail.”
The particular meteorites used for this study are known as pallasites, which are primarily composed of iron and nickel, studded with gem-quality silicate crystals.
The researchers’ magnetic measurements, supported by computer simulations, demonstrate that the magnetic fields of tpallasites were created by compositional, rather than thermal, convection – meaning that the field was long-lasting, intense and widespread. “This changes our perspective on the way magnetic fields were generated during the early solar system,” Harrison concluded. Their results were published in the journal Nature.
The Earth will eventually lose its magnetic field as its solid inner core gets better and the liquid outer core disappears, and when it’s gone we’ll no longer be protected from the Sun’s radiation.
“There’s no need to panic just yet, however,” Harrison says. “The core won’t completely freeze for billions of years, and chances are, the Sun will get us first.”
what will happen to earth if its core freezes?
The Earth’s core affects the planets magnetic field. As it freezes, the magnetic field weakens. The process has already begun. Recent research have found that the magnetic field has weakened by 15 per cent over the last 200 years. With a weakened magnetic field, the planet could be exposed to solar winds capable of punching holes into the ozone layer. The impact could be devastating for mankind, knocking out power grids, radically changing Earth’s climate and eventually leading to the planet’s demise.
‘This is serious business’, Richard Holme, Professor of Earth, Ocean and Ecological Sciences at Liverpool University told MailOnline. ‘Imagine for a moment your electrical power supply was knocked out for a few months – very little works without electricity these days.’
The Earth’s climate would change drastically. In fact, a recent Danish study believes global warming is directly related to the magnetic field rather than CO2 emissions.
Radiation at ground level would also increase, with some estimates suggesting overall exposure to cosmic radiation would double causing more deaths from cancer.
If the magnetic field continues to decline, over billions of years, Earth could end up like Mars – a once oceanic world that has become a dry, barren planet incapable of supporting life
Source ~ DailyMail: http://goo.gl/c3jAXf
Journal reference: http://goo.gl/c3jAXf.