Scientists say that they have observed a star in our galaxy that races around a black hole at a breakneck speed, orbiting once every 2.4 hours. The black hole in the spinning duo is known as MAXI J1659-152 and is at least three times more massive than the sun. The star is a red dwarf with a mass just one-fifth that of the sun and is just 620,000 miles from the black hole, according to the European Space Agency.
"The companion star revolves around the common center of mass at a dizzying rate, almost 20 times faster than Earth orbits the sun," astronomer Erik Kuulkers, of ESA's European Space Astronomy Centre in Spain, said. "You really wouldn't like to be on such a merry-go-round in this galactic fair!"
The two objects orbit a common center of mass. Because the star is the lighter, it has a larger orbit and has to travel at a remarkable speed of 1.2 million mph, making it the fastest moving star ever seen in an X-ray binary system. The black hole orbits at about 93,000 mph, ESA officials said. The space agency created a video animation of the black hole and ultra-fast star to illustrate the odd setup.
The pair was initially thought to be a gamma-ray burst when NASA's Swift space telescope first spotted it. Japan's MAXI telescope on the International Space Station also observed a bright X-ray source at the same place. More observations revealed that the X-rays came from a black hole siphoning material from a tiny star companion. From dips in these X-ray emissions during a 14.5-hour observation with ESA's XMM-Newton space telescope, astronomers calculated that the star's orbital period was just 2.4 hours. This orbital period smashes the previous record of 3.2 hours, held by Swift J1753.5–0127.
The newfound pair lies high above the galactic plane, meaning it is out of the main disc of our spiral Milky Way galaxy, a characteristic shared by only two other black-hole binary systems, including Swift J1753.5–0127. "These high galactic latitude locations and short orbital periods are signatures of a potential new class of binary system, objects that may have been kicked out of the galactic plane during the explosive formation of the black hole itself," Kuulkers said.
Warren Buffet, one of the world's richest investors, says the total amount of gold in the world - the gold above ground, that is, could fit into a cube with sides of just 20m (67ft). A figure that is widely used by investors comes from Thompson Reuters GFMS, which produces an annual gold survey. Their latest figure for all the gold in the world is 171,300 tonnes, which is almost exactly the same as the amount in our super-villain's imaginary cube.
A cube made of 171,300 tonnes would be about 20.7m (68ft) on each side. It would reach to 9.8m above ground level if exactly covering Wimbledon Centre Court. Everyone may not agrees with the GFMS figures. Estimates range from 155,244 tonnes, marginally less than the GFMS figure, to about 16 times which amount to 2.5 million tonnes. This figure would make a cube of sides 50m (166ft) long, or a column of gold towering 143m above Wimbledon centre court.
Reason for the different figures are that gold has been mined for a very long time, more than 6,000 years. All the gold that has been mined throughout history is still in existence. The first gold coins were minted in about 550 BC under King Croesus of Lydia and quickly became accepted payment for merchants and mercenary soldiers around the Mediterranean.
Until 1492, the year Columbus sailed to America, GFMS estimates that 12,780 tonnes had been extracted. But one investor James Turk, the founder of Gold Money, discovered what he regarded as a series of over-estimates. He believes that the primitive mining techniques used up to the Middle Ages mean that this figure is much too high, and that a more realistic total is just 297 tonnes.
Tonnes of gold GFMS James Turk
Pre-1492 12,780 297
Post-1492 158520 154947
Total 171,300 155,244
His figure for the overall amount of gold in the world is 155,244 tonnes, 16,056 tonnes, or 10% less than the assessment by Thompson Reuters GFMS. A relatively small disparity, perhaps. His conclusions are accepted by some investors. But there are others who think both sets of figures are too low. "In Tutankhamen's tomb alone they found that his coffin was made from 1.5 tonnes of gold, so imagine the gold that was found in the other tombs that were ransacked before records were taken of them," says Jan Skoyles of gold investment firm The Real Asset Company.
While James Turk makes only minor adjustments to the GFMS figure for the amount of gold mined after 1492, Skoyles points out that even today China is "not particularly open" about how much gold it is mining. And in some countries, such as Colombia, "there's a lot of illegal mining going on", she says. She doesn't have an exact figure to offer, but one organisation that has tried to do some maths is the Gold Standard Institute.
There is much gold still in the ground, like here in Democratic Republic of Congo. Its experts believe that if we emptied our bank vaults and jewellery boxes, we'd find no less than 2.5 million tonnes of gold, though they admit that the evidence is somewhat sparse and the figure is a bit speculative. All these numbers are made up of estimates added to estimates added to yet more estimates.
The good news is that we are not likely to run out of gold any time soon. The US Geological Survey estimates there are 52,000 tonnes of minable gold still in the ground and more is likely to be discovered. The bad news is that the way we use gold is starting to change. Up till now it has never gone away. It has always been recycled. "All the gold that has been mined throughout history is still in existence in the above-ground stock. That means that if you have a gold watch, some of the gold in that watch could have been mined by the Romans 2,000 years ago," says James Turk.
The way gold is being used in the technology industry, however, is different. The British Geological Survey states that about 12% of current world gold production finds its way to this sector, where it is often used in such small quantities, in each individual product, that it may no longer be economical to recycle it.