快猫短视频

SO MUCH for Moore鈥檚 Law. In 1965, Gordon Moore, one of the founders of chip
maker Intel, predicted that the number of transistors that can be packed into
memory chips would keep on doubling every 18 months. While his law shows no sign
of being broken any time soon, a scientist has harnessed black hole physics to
show that computer memories cannot go on storing more and more information
forever鈥攁nd that the ultimate storage limit is much closer than engineers
thought.

Jacob Bekenstein, a physicist at the Hebrew University of Jerusalem, says
that black holes are the perfect information-storage devices because they鈥檙e the
densest objects in the Universe. But how much information can a black hole
store? In the 1970s, he worked out that a black hole with a 1-centimetre-radius
event horizon could hold about 10⁶⁶ bits. By contrast, the books in the Library
of Congress in Washington DC collectively hold only 10¹⁵ bits.

But Bekenstein now says his initial calculation relied only on very basic
physics, and that thinking about information falling into a black hole gives a
better estimate. He now concludes that a 1-centimetre black hole can鈥檛 hold more
than 10³⁷ bits of information鈥攎any orders of magnitude less than he
originally thought. 鈥淭his limit no longer looks unreachable,鈥� he says.

The calculation is important because it places an ultimate limit on the
capacity of computer memories, regardless of what technologies you use to
construct them. 鈥淵ou could use atoms, electrons and eventually quarks to store
information鈥攂ut the device could never exceed this capacity, whatever the
technology,鈥� he says.

Bekenstein has also shown that there is a limit to the rate at which
information can be fed into a black hole. While this sounds bizarre, it may have
ramifications for government and military agencies developing the electronic
equivalent of document shredders to destroy classified information鈥攚hich
is surprisingly difficult. 鈥淲hat this tells us is that you have to pay a price
for destroying information. It takes energy,鈥� says Bekenstein.

But computer scientists are happy to rely on Moore鈥檚 Law for some years yet.
鈥淲e are a long way from this limit. But it does tell us that there is a lot of
space in small systems which we are not using,鈥� says Vlatko Vedral, a
theoretical physicist at Imperial College, London. 鈥淚 see no reason why we
shouldn鈥檛 reach the Bekenstein limit one day.鈥�