Science and Technology News

65 million years ago, the dinosaurs were wiped out by at least two meteorite impacts, rather than one single hit, new research has found.

Before the new study, scientists had identified a large impact crater in the Gulf of Mexico as the event that ended the reign of the dinosaurs.

Evidence for a second impact in the Ukraine has been found.

This raises the possibility that the Earth may have been bombarded by a shower of meteorites.

The new study is being published in the journal Geology by team lead Professor David Jolley of Aberdeen University.

When it was first proposed in 1980, the concept of a meteorite impact killing the dinosaurs was a hugely controversial. However, the discovery of the Chicxulub Crater in the Gulf of Mexico, was hailed as “the smoking gun” in the now confirmed theory.

The discovery of a second impact crater suggests that the dinosaurs were drive to extinction by a “double whammy” rather than a single strike.

In Ukraine, the Boltysh Crater was first found in 2002. However, it was uncertain until now exctly how the timing of the event coincided with the Chicxulub impact.

In the new study, scientists looked at the “pollen and spores” of fossil plants in the layers of mud that filled up the crater. They found that immediately after the impact, ferns colonized the landscape.

Ferns have an incredible ability to bounce back after catastrophe. Layers of fern spores, called “fern spikes”, are considered to be good markers of past impact events.

There was an unexpected discovery for the scientists, however.

They found another “fern spike” an a layer about 4 feet above the first, suggesting that another impact event happened later.

Professor Simon Kelley of the Open University, who was co-author on the study, said, "We interpret this second layer as the aftermath of the Chicxulub impact".

This is proof that the Boltysh and Chicxulub impacts did not happen at exactly the same time. They struck several thousand years apart, the length of time between the two “fern spikes”.

Professor Kelley added, “It is quite possible that in the future we will find evidence for more impact events".

Rather than being wiped out by one hit, the researchers think that dinosaurs think that the dinosaurs may have been victim of a meteorite shower raining down over thousands of years.

It is still uncertain what may have caused the bombardment.

Professor Monica Grady, an expert on meteorites at the Open University who was not involved in the study, said, "One possibility might be the collison of Near Earth Objects".

NASA recently launched a program celled “Spaceguard”. It hopes to monitor Near Earth Obhects for an early warning system of possible future collisions.

Facebook users have been victims of a scam that offers one to install a “dislike” button into their profile.

The application tricks users into allowing an external application to access their profile page, which posts a spam message.

Additionally, it attempts to lure people into completing an online survey that the scammers are then paid for.

The social network offers a “like” button already that lets people rate user's comments and posts.

Graham Cluley of the security firm Sophos said it was the newest in a line of “survey scams” that included links to a video claiming to show an anaconda vomiting up a hippo.

"One thing we commonly see is that the message starts 'OMG, shocking video'," he said.

"And they appear to come from your Facebook friend, giving it a ringing endorsement."

The dislike button scam tells people to download the application with a message that reads, "Download the official DISLIKE button now."

When users click the link, it instructs them to install a third party application, which does not function as a dislike button.

Once a user has given permission to access their profile, it updates the user's page with a new link and a message that reads, "I just got the dislike button, so now I can dislike all of your dumb posts lol!!!"

"Many people are giving permission for completely unknown apps," Mr Cluley told BBC News.

The surveys appear to be from genuine companies, he said.

"As far as we can tell, they appear to be legitimate," he said. "It could be that the firms are not policing their affiliates properly."

The scams directs installers to a Firefox add-on that installs a “dislike” button.

According to Mr Cluley, the add-on appears to be legitmate.

The makers of the app could not be reached for comment.

A spokesperson for Facebook said that the site had a “very quick process in place” that makes sure that links and rogue applications are taken down quickly.

"We always encourage people to not click on links that appear suspicious - even if posted from a friend," a spokesperson said.

"They can report any posts to us. We can make sure that we take down any application or all of the links across Facebook."

Mr Cluley said that even though Facebook can respond very fast, it should police their application development more thoroughly.

"Anyone can write a Facebook app - these scams are constantly springing up," he said.

Apple has patched a hole in security that circumvented restrictions on what some applications can run on iPhones, iPads and the iPod Touch.

The JailbreakMe application used the same vulnerability to unlock the devices to run non-approved applications.

The bug came from the way Apple's mobile Safari browser managed PDF document files.

Security experts warned that it left open some users to be vulnerable to attack via booby-trapped sites.

The risk was all theoretical, since no criminals have been thought to exploit the security hole.

It is widely used to run applications, utilities and add-ons that are not approved by Apple.

The company has a tight watch on the apps available in the store and a lot of people turn to alternatives like Cydia for unofficial applications.

The lapse in security was first used for the JailbreakMe program that allows used to visit a cleverly crafted webpage to trigger the process.

The newest patch will keep JailbreakMe from working, but will seal up a vulnerable spot that, if exploited, could give attackers access to the mobile devices.

The updates will be given to owners when they connected the device to a computer for updates.

The company and security experts recommended that owners download and install the update immediately.

However, the update is not required, and a lot of people may avoid downloading and installing it to make sure they can still run unofficial applications.

"It remains to be seen, of course, how many iPhone and iPad users decide to install this security patch," said Sophos senior security analyst Graham Cluley on his blog.

"Some may be delighting in their newly-jailbroken gadget."

Mr Cluley said leaving the vulnerability unpatched would be a "foolish move".

"It would be relatively trivial for a malicious hacker to exploit it, and cause a problem on your shiny Apple gear," he warned.

In its update, Apple said that it applies to second generation and later iPods and the iPod Touch. A security package that fixes the bug on first generations devices is being developed by a progammer named Jay Freeman.

Computers capable of performing a quintillion (10 to the 18^th power) calculations per second are being planned by the military.

The Defense Advanced Research Projects Agency (DARPA) has awarded the first grants to firms it wants to build the so-called exascale computers.

These new machines will far exceed the power of the highest perfrming supercomputers of today which manage just over one petaflop (1000 trillion calculations per second).

The first prototypes are expected to be working by 2018.

An exaflop is the equivalent of one million trillion calculations per second.

DARPA says its research project is needed to help analyze the immense amounts of data that military systems and sensors create.

The research project, called the Ubiquitous High Performance Computing (UHPC) program, would try to create hardware that “overcomes the limitations of current evolutionary approach".

The idea is characterized by Moore's Law, which says that the number of transistors that can fit onto a given piece of silicon will double every 18-24 months.

The limitations of the approach are the mushrooming power, management and structural issues that come up as components shrink.

To avoid the limitations, grant recipients will have to remake chips that use “dramatically” less power per calculation.

The ultimate goal of the project is to “re-invent computing” said the agency in a statement.

It is looking to "develop radically new computer architectures and programming models that are 100 to 1,000 times more energy efficient, with higher performance, and that are easier to program than current systems".

Intel, the chip making giant, graphics card maker Nvidia, MIT and the Sandia National Laboratory are all recipients of the first grants to be used to create prototype exascale machines.