Beta Pictoris up close

63 light years from Earth, Beta Pictoris is surrounded by a protoplanetary disc in the process of forming planets. Take a tour around it now…

Many of today’s superfast rollercoaster Anatomy of a launcher rides wouldn’t get anywhere without special launching mechanisms. These mechanisms are typically powered by hydraulics and grant incredible speeds to the coaster’s train; indeed, the fastest in the world can achieve 240 kilometres (150 miles) per hour, which it reaches in under five seconds.

Key to a hydraulic launch system is its ‘catch car’, which runs underneath the coaster’s train and track. The car is responsible for receiving the energy generated by the launcher’s hydraulic motors and mechanisms and converting it into linear motion. The catch car does this by effectively towing the train down a portion of the track at high speed, with it then detaching at the last moment, leaving the train and its passengers free to zoom away.

Rollercoaster launchers

These hydraulic coaster launch mechanisms share much technology with aircraft carrier launch systems for fighter jets, with both situations requiring the vehicle to be propelled to high velocity within a short distance and timeframe. Both the fastest and tallest rollercoasters in the world – the Ferrari-built Formula Rossa in Abu Dhabi, UAE, and the Kingda Ka in the USA, respectively – use hydraulic launch systems for propulsion.


Rollercoaster launchers

Learn about the engineering that propels thrill-seekers to 240km/h in mere seconds

The Goubet I submarine was a two-person, electric submarine built by French inventor Claude Goubet in 1885. Manufactured in Paris, the sub has gone down in history as the first to be electrically powered, with a brace of cutting-edge tech advancing more primitive models.

The Goubet I was battery powered, utilised a Siemens electric motor to drive its propeller and power a navigation light, and measured five metres (16.4 feet) long. The craft weighed in at just over six tons. It was controlled from a central position, with its two crew positioned back to back, seeing out of the vessel via small glass windows; they could see up, down and to the sides to some extent thanks to prisms.

After testing in the River Seine in Paris, however, the Goubet I was ultimately deemed a failure, because the submersible wasn’t able to maintain a stable course or depth while moving forward. As a result, while some of its innovative technology lived on in later designs, the Goubet I itself was quickly scrapped.


The first electric submarine

Learn about the Goubet I – the earliest underwater vessel to be electrically powered

Built in the Nineties, the Sudbury Neutrino Observatory (SNO) is currently being refurbished to refocus its sights on some of the latest questions in neutrino research. Baptised SNO+, the new detector will reuse much of its predecessor’s infrastructure to hunt for the products of neutrino interactions but using a slightly different technique. Instead of heavy water, SNO+’s tank will be filled with a scintillator: a liquid that gives off light when charged particles pass through it. This will enable SNO+ to spot lower-energy neutrinos than before, broadening the scope of the facility’s research.


Inside Sudbury Neutrino Observatory

Take a short tour of this important neutrino hunting lab now

Whaling ships – otherwise known as whaleships during the 19th century – were sea vessels that were carefully designed for long-haul and dangerous operations. Manned by a skilled crew, their sole purpose was to hunt, capture and asset strip a variety of whales – notably baleens – across some of Earth’s wildest oceans.

‘Assets’ consisted primarily of blubber – a layer of thick body fat found under the skin of all whales, which could be rendered down for its heavy oil content – though bones, meat and other parts were also salvaged. Oil, however, was the major goal for any whaleship, as prior to the introduction of kerosene and vegetable oils, whale oil was the backbone of many everyday products including soap, lamps and even foods. As a result, every whale that was caught could bring in a tidy profit back on land.

Oil was harvested from blubber on board the vessel in a ‘try-works’ – a processing system that consisted of two try-pots and a brick furnace. The blubber was boiled in the pots on the furnace, where its natural oils were siphoned off and stored in large casks below deck. The furnace itself was mounted on cast-iron struts to the deck, with a reservoir of underlying water to prevent the wooden planks from burning. Of course, to render the blubber first the crew needed to capture a whale.

The process of catching whales entailed hitting the creature with deck-mounted harpoon guns and then approaching on smaller whaleboats. Each whaleboat – which were carried like lifeboats on larger ships today – had its own crew and selection of arms, such as handheld harpoons, spears and guns. The carcass was then towed by the whaleboats back to the ship and ‘flensed’ – which involved the skin and blubber being cut off in strips before it was taken on board.


Life on board a 19th-century whaling ship

How did these specialist vessels help a crew hunt down the highly prized marine mammals on perilous sea voyages that could last for months?

How It Works Facebook Activity

It is estimated that a third of the stars in the Milky Way are part of a binary (two) or multiple (three upwards) star system, with more than one star orbiting a common centre of mass, or barycentre.

Depending on the mass of each star and the conditions of their formation, they can be quite close together or millions of miles apart, and the time it takes for them to orbit varies from hours to millennia. Binary star systems are particularly useful to astronomers because they can accurately determine the mass of the stars by analysing their orbits; this then enables them to estimate the mass of similarly bright lone stars.

Some binaries can be seen through a telescope, but many are only detected indirectly, either when one star eclipses another, or when the wavelengths of light emitted vary as the stars circle around their barycentre.

If the stars are close enough together, their gravitational pull enables them to exchange matter; this can be seen as a bright disc around the recipient star. If the recipient is a white dwarf, hydrogen received from its companion can be compressed by the intense gravity at the core and undergo nuclear fusion. This process releases huge amounts of energy, which can be seen as a nova. In some cases the energy can be so great that it triggers a supernova event, destroying the star.

Binary star systems can also drift apart, resulting in the formation of single stars. The breakup of multi-star systems can also occur due to close interaction with neighbouring celestial bodies, causing dramatic fluctuations in gravitational pull and leading to stars being thrown out of a system. These ‘runaway stars’ have been seen hurtling through space at speeds of up to 30 kilometres (18.5 miles) per second.


Binary stars explained

How do multi-star systems form – and do planets exist where the sun sets twice?

The Eagle Nebula is a star-forming region of the universe located within the dense Carina-Sagittarius spiral arm of the Milky Way. The towering ‘Stellar Spire’ column of ultra-cold dust and ionised gas which is pictured here represents just a tiny portion of the nebula. The dense gases and solid-butminuscule particles inside nebulas are the major ingredients necessary for creating young stars. New stars form when clumps of this gassy, dusty matter collapse under gravity.

The Eagle Nebula would appear dark to us were it not for the intense light coming from nearby star clusters, which illuminate the interstellar matter from behind. The atoms of gas and dust in emission nebulas like this glow due to energy from local stars.

Stars don’t just make nebulas easier to see; they also create some pretty unusual formations inside them. The star-making dust and gas of the Stellar Spire has been boiled away by the ultraviolet (UV) radiation emitted by stars formed in the nebula, leaving behind a dramatic sculpted pillar.

Within the main nebula a cavernous hollow has formed a protective shell around an open cluster of stars that continues to form and give out light energy. This cold wall of dust and gas is being pushed back by the UV radiation, boiling away the lower-density stellar material to leave behind the denser matter in the shape of tall towers with globules of dark dust and gas on their surfaces.

The three Pillars of Creation, famously photographed by the Hubble telescope in 1995, are examples of such dust columns surrounded by glowing ionised gas. They are thought to be the birthplace of many stars.


The Eagle Nebula explored

What goes on inside this stellar nursery and what can it tell astronomers about the complex process of star formation?

Both in Homeric and post-Homeric Greece, hoplite warriors were considered the most deadly and efficient soldiers on the planet. Armed with a variety of highly refined weapons – such as spears, swords and daggers, protected by toughened bronze armour and adept at executing cunning tactics and formations, these Ancient Greek warriors tore through many an enemy army with considerable ease.

Arguably, hoplites really came into their own around the sixth century BCE. Prior to this point Greek warriors – who were self-armed and trained civilians – fought for personal, familial or national honour singularly. They obviously grouped under city-state banners to wage wars, but when the battle started, the onus was very much on man-to-man single combat; indeed, many battles of this period began with army commanders/heroes facing off against each other solo.

After the introduction of advanced military formations such as the phalanx – see ‘Wall of death’ boxout for more – circa 700 BCE, soldiers began to fight battles as cohesive military units. This increased their battle prowess further and, by the time of the massive Persian invasion of 480 BCE, enabled them to win a series of decisive battles against forces that, going on the numbers, they should have lost.


Greek warriors

The hoplites of Ancient Greece were some of the most feared fighters in the world – find out why

Sit-on lawnmowers typically feature a diesel engine, which uses two drive belts: one to turn the wheels and one to turn the rotating blades. The controls are similar to a car’s, with gears, pedals and a steering wheel.

Most ride-on mowers have a series of rotary steel blades; these spin horizontally across the ground, creating upwards suction, which draws in the grass. The spinning blade cuts the grass very roughly and can cause discolouration due to bruising and tearing. Controls allow blade height to be adjusted, so they can be lifted and disengaged from the engine while the vehicle is being driven.

For high-quality lawns, a reel mower is used instead. These have a fixed cutting bar, which is positioned parallel to the grass; as the mower moves over the lawn a series of spiral blades attached to a reel above the fixed blade spin rapidly, pushing the grass past the bar. The gap between the reel and the bar is kept at approximately the thickness of a blade of grass, which ensures a super-clean cut.

Rollers are sometimes added to mowers to smooth the grass after it has been cut and to cover up any wheel marks. These are also responsible for creating the characteristic stripy look often seen on football pitches and ornamental lawns.


Ride-on lawnmowers

Find out how these diesel-powered cutting machines which you can drive help keep huge sports fields and lawns neat and trim

Brachiosaurus was a genus of sauropod dinosaur that roamed the Earth during the Late Jurassic period (circa 155-140 million years ago). They are characterised, like many sauropods of the time, by their huge necks and comparatively tiny skulls and brains. Currently only one species has been officially confirmed – B altithorax – though others have been suggested.

Interestingly, like other sauropods, these creatures – despite weighing an estimated 60 tons and measuring up to 30 metres (98 feet) long – were actually colossal vegetarians, with their diet comprising solely foliage.

Their evolution of such a long neck (see ‘The high life’ boxout for more details) seems to be intrinsically linked to their diet, with the elevated head position enabling them to access leaves unavailable to shorter species.

This dominion over a food source is also a major factor behind their generally massive proportions, with millions of years of domination allowing them to grow to sizes far in excess of rival creatures from the same era.

The epic size of Brachiosaurus was also its primary form of defence when it came to predators. Once fully grown, their legs would have resembled tree trunks and these – partnered with a heavy, stocky tail – made them extremely difficult to tackle.

While their size and domination granted many benefits, it was also a contributor to Brachiosaurus’s eventual demise, with resource depletion and climate change leading to their background extinction around 145 million years ago.


The giant Brachiosaurus

Three times longer and two times taller than a double-decker bus, Brachiosaurus truly was a terrestrial titan of epic proportions

On the island of Palawan in the Philippines is a layer of limestone over 500 metres (1,640 feet) thick. The rock is honeycombed with a complex network of caves – some big enough to hold jumbo jets – that have formed due to running water from rain and streams. Deep inside the limestone is the Puerto Princesa Subterranean River, which flows 8.2 kilometres (five miles) through a warren of passages to the sea.

Underground rivers like the Puerto Princesa are found worldwide in a type of limestone terrain called karst. These dramatic landscapes are riddled with huge caves, pits and gorges. Famous examples include the South China Karst, which covers 500,000 square kilometres (193,000 square miles) of China’s Yunnan, Guizhou and Guangxi provinces.

Karst forms when acid water seeps down tiny cracks, called joints, in the limestone. The acid slowly eats away the rock and enlarges the joints into vertical shafts and horizontal passages. Rivers flowing onto limestone often vanish from the surface down shafts called swallow holes and continue as underground waterways. Generally, dry valleys signal where the river once flowed on the surface.

Over millions of years, underground rivers can carve out huge cave networks – some that extend for hundreds of kilometres. Higher caves are left abandoned when gravity causes the river to drain into lower passages. The water seeps down through the limestone until it reaches impermeable rocks, then flows horizontally until it emerges near the base of the karst as a spring or waterfall.

During floods, or when the water table rises, the river can totally fill a cave and erode its roof. When the water retreats, the unsupported ceiling may crumble. The Reka Valley in Slovenia – a 100-metre (328-foot)-high gorge – formed when a cave collapsed centuries ago. This means the Reka River, which primarily runs underground through the Škocjan Caves, now sees daylight for part of its journey.


Subterranean rivers

Discover how, over many millennia, water can create spectacular cave systems and secret waterfalls all hidden deep beneath the ground

Monorails have been around since the 1800s, but only really came to public attention in the 1950s when Walt Disney installed one in his new theme park: Disneyland, California. In most parts of the world their use is still restricted to amusement parks, however in Asia – particularly Japan – they also play an important role in public transport around major metropolises.

Modern monorails are based on a single solid beam that supports and guides the train; the carriages are either suspended beneath the track, or sit on top, with their wheels straddling electricity, which is carried on a ‘third rail’ either within, or connected to, the main beam. Conductive shoes on the carriages then transmit the current to the train.

How monorails work

The straddle-beam design is the most widely used. The carriages have pneumatic rubber tyres, which drive along the top of an ‘I’-shaped beam. To prevent side-to-side swaying of the train, a series of smaller tyres clamp around the beam, providing general stability and also helping to guide the carriages.

Suspended monorails, meanwhile, hang underneath the track. The design can be a where the cars hang from the underside of the ‘I’ beam, or alternatively the wheels can sit inside a hollow steel girder. In the latter case, the wheels are completely enclosed, protecting them from the elements and making the train extremely difficult to derail.


In fact, monorails are one of the safest forms of transport. The elevated track minimises interaction with traffic and pedestrians, eliminating the need for crossings, and derailment is very rare. They are energy efficient too and their rubber tyres produce the beam. They are usually powered by simple inversion of the straddle monorail, much less noise pollution than the metal wheels of conventional trains.


How monorails work

How do these trains stay balanced on one rail – and even hover above it?