How It Works

Friday 28 November 2014

NASA 3D prints on the ISS

History has been made as the 3D printer on board the ISS created a faceplate, which became the first item ever to be 3-D printed in space.

The printer was taken up to the space station earlier this month and was installed on 17 November by astronaut Barry Wilmore. After a series of tests to fine-tune the calibration, ground control commanded the printer to 3D print the plate.

The primary objective of the experiment was to see if microgravity altered the bonds created by the machine and it was discovered that the bonds were strengthened in the low gravity environment.

After another re-calibration, the team will attempt a second printing.

How the internet has changed our lives in the past 25 years

It has been 25 years since the launch of the first-ever commercial internet service provider (ISP) in November 1989, and technology has changed quite a lot since.

For example, 25 years ago there were just 159,000 hosts or websites worldwide, now there are more than 1 billion, and the basic iPhone 5S is 65 times faster and has 8,000 times more memory than a PC in 1989.

Also:

A 4GB Kindle can now store 3,000 books, but a mobile library carrying that many books in 1989 would have weighed 9,000 kilograms (19,840 pounds).
The 220,000 photos uploaded to Instagram every minute in 2014 would have used up 9,116 camera film rolls in 1989.
Sending the 2.3 million emails that are now sent every second would have cost you £1.24 million ($1.95 million) in 2nd class stamps in 1989.

To find out more fascinating facts about how the internet has changed out lives in the past 25 years, check out this interactive graphic.

Wednesday 19 November 2014

Gecko-inspired gloves let you scale walls of glass

Being able to scale walls like Spider-Man has just gone from being comic-book fiction to an exciting reality.

A newly developed synthetic adhesion system inspired by geckos has been created and tested, enabling a 70-kilogram (154-pound) human to scale a 3.6-metre (12-foot) pane of glass. You can see the test in the video below.

A gecko’s feet are covered in tiny hairs called setae, which are split into even smaller bristles called spatulae. These spatulae create an electromagnetic force, known as van der Waals force, which enables them to stick to almost any surface. Although this force is very weak, the gecko’s lightweight body and shear number of spatulae, make it possible to climb up walls and across ceilings.

A team of US scientists, led by Dr Elliot Hawkes from Stanford University, took inspiration from geckos to create tiny tiles called ‘microwedges’, which generate van der Waals force and produce a dry adhesive. These microwedges were then applied to pads that enabled a human to pull themselves up a wall of glass.

Sunday 16 November 2014

How Does BitTorrent Work?

When you download a web page like this one, your computer connects to the web server and downloads the data directly from that server. Each computer that downloads the data downloads it from the web page’s central server. This is how much of the traffic on the web works.

BitTorrent is a peer-to-peer protocol, which means that the computers in a BitTorrent “swarm” (a group of computers downloading and uploading the same torrent) transfer data between each other without the need for a central server.

Traditionally, a computer joins a BitTorrent swarm by loading a .torrent file into a BitTorrent client. The BitTorrent client contacts a “tracker” specified in the .torrent file. The tracker is a special server that keeps track of the connected computers. The tracker shares their IP addresses with other BitTorrent clients in the swarm, allowing them to connect to each other.

Once connected, a BitTorrent client downloads bits of the files in the torrent in small pieces, downloading all the data it can get. Once the BitTorrent client has some data, it can then begin to upload that data to other BitTorrent clients in the swarm. In this way, everyone downloading a torrent is also uploading the same torrent. This speeds up everyone’s download speed. If 10,000 people are downloading the same file, it doesn’t put a lot of stress on a central server. Instead, each downloader contributes upload bandwidth to other downloaders, ensuring the torrent stays fast.

Importantly, BitTorrent clients never actually download files from the tracker itself. The tracker participates in the torrent only by keeping track of the BitTorrent clients connected to the swarm, not actually by downloading or uploading data.

Leechers and Seeders

Users downloading from a BitTorrent swarm are commonly referred to as “leechers” or “peers”. Users that remain connected to a BitTorrent swarm even after they’ve downloaded the complete file, contributing more of their upload bandwidth so other people can continue to download the file, are referred to as “seeders”. For a torrent to be downloadable, one seeder – who has a complete copy of all the files in the torrent – must initially join the swarm so other users can download the data. If a torrent has no seeders, it won’t be possible to download – no connected user has the complete file.

BitTorrent clients reward other clients who upload, preferring to send data to clients who contribute more upload bandwidth rather than sending data to clients who upload at a very slow speed. This speeds up download times for the swarm as a whole and rewards users who contribute more upload bandwidth.

Torrent Trackers and Trackerless Torrents

In recent times, a decentralized “trackerless” torrent system allows BitTorrent clients to communicate among each other without the need for any central servers. BitTorrent clients use distributed hash table (DHT) technology for this, with each BitTorrent client functioning as a DHT node. When you add a torrent using a “magnet link”, the DHT node contacts nearby nodes and those other nodes contact other nodes until they locate the information about the torrent.

As the DHT protocol specification says, “In effect, each peer becomes a tracker.” This means that BitTorrent clients no longer need a central server managing a swarm. Instead, BitTorrent becomes a fully decentralized peer-to-peer file transfer system.

DHT can also work alongside traditional trackers. For example, a torrent can use both DHT and a traditional tracker, which will provide redundancy in case the tracker fails.

BitTorrent Isn’t Just For Piracy

BitTorrent isn’t synonymous with piracy. Blizzard uses a custom BitTorrent client to distribute updates for its games, including World of Warcraft, StarCraft II, and Diablo 3. This helps speed up downloads for everyone by allowing people to share their upload bandwidth with others, leveraging unused bandwidth towards faster downloads for everyone. Of course, it also saves Blizzard money on their bandwidth bills.

People can use BitTorrent to distribute large files to significant numbers of people without paying for the web hosting bandwidth. A free film, music album, or game could be hosted on BitTorrent, allowing an easy, free method of distribution where the people downloading the file also help distribute it. WikiLeaks distributed data via BitTorrent, taking a significant load off their servers. Linux distributions use BitTorrent to help distribute their ISO disc images.

BitTorrent, Inc. – a company responsible for developing BitTorrent as a protocol, who also purchased and develop the popular µTorrent torrent client – is developing a variety of applications that use the BitTorrent protocol for new things via their BitTorrent Labs project. Labs experiments include a syncing application that securely synchronizes files between several computers by transferring the files directly via BitTorrent, and a BitTorrent Live experiment that uses the BitTorrent protocol to help broadcast live, streaming video, leveraging the power of BitTorrent to stream live video to large numbers of people without the current bandwidth requirements.

starcraft-2-peer-to-peer-download-feature

BitTorrent may be primarily used for piracy at the moment, as its decentralized and peer-to-peer nature are a direct response to efforts to crack down on Napster and other peer-to-peer networks with central points of failure. However, BitTorrent is a tool with legitimate uses in the present — and many other potential uses in the future.

Why can't we remember being babies?

You gaze at the cheerful crowd gathered around you, take a curious look at the chocolate cake set before you and then, just as the everyone starts singing "Happy Birthday," you do what comes naturally: smash the cake with both hands.

This scenario would be weird, except for the fact that you're sitting in a highchair. Which would be even weirder, except that you're turning 1.

Chances are you don't remember your first or second birthday party -- or a host of other events that occurred in early childhood -- and you're not alone. It's normal to forget your earliest life experiences, despite their crucial and influential nature.

Most adults can't recall life's earliest moments unless the events are reinforced by others who often retell them, or the memories are triggered by photographs or other cues.

It's a phenomenon scientists callchildhood amnesia. While you may have been able to recall and describe your second birthday party in great detail for months after it happened, a year later those memories may have faded and, eventually, are lost altogether.

Researchers point to a high turnover rate of childhood memories as one possible culprit, believing that a raft of new experiences simply means some early memories are forced to fall by the wayside.

Up until age 3, children in one study could recall significant events that happened to them within the last year. The high rate of recall continued until age 7, with the study's participants remembering up to 72 percent of the same events they'd recalled as 3-year-olds. By age 8 or 9, however, most could recollect only 35 percent of the life experiences they'd so vividly described at 3 [source: Gray].

The change, concluded researchers, comes from the way memories are formed as children age. Beginning at 7, children store increasingly linear memories that fit succinctly into a sense of time and space. The very act of remembering events and categorizing them within this personal timeline may cause retrieval induced forgetting, a process that causes older children and adults to prune life's earliest memories as they recall specific details about other events

How does laughing gas work?

Laughing gas – or nitrous oxide – is a colourless gas with a sweet odour and taste. Its principle use is as an anaesthetic in surgical operations, however due to its unique properties, it has been used for other non-medical purposes too. Its use as a stimulant – from which it acquired its name – grants the inhaler a short period of insensibility to pain, euphoria and a tendency to mild hysteria (ie laughter). The gas has this effect as it both modulates a broad range of ligand-gated ion channels in the user’s nervous system and partially/fully inhibits NMDAR-mediated currents (the NMDA receptor is the brain’s predominant molecular device for controlling synaptic plasticity and memory function).

Importantly, however, while nitrous oxide is still sold and used for recreational purposes, scientific trials have discovered that it causes neurotoxic damage to the posterior cingulate and retrosplenial cortices of the brain (areas involved with awareness and memory), and that prolonged use will lead to death.