Category Science

Pulsars are spherical, compact objects that are about the size of a large city but contain more mass than the sun. Scientists are using pulsars to study extreme states of matter, search for planets beyond Earth’s solar system and measure cosmic distances. Pulsars also could help scientists find gravitational waves, which could point the way to energetic cosmic events like collisions between supermassive black holes. Discovered in 1967, pulsars are fascinating members of the cosmic community. 

Pulsars radiate two steady, narrow beams of light in opposite directions. Although the light from the beam is steady, pulsars appear to flicker because they also spin. It’s the same reason a lighthouse appears to blink when seen by a sailor on the ocean: As the pulsar rotates, the beam of light may sweep across the Earth, then swing out of view, then swing back around again. To an astronomer on the ground, the light goes in and out of view, giving the impression that the pulsar is blinking on and off. The reason a pulsar’s light beam spins around like a lighthouse beam is that the pulsar’s beam of light is typically not aligned with the pulsar’s axis of rotation.

Some pulsars also prove extremely useful because of the precision of their pulses. There are many known pulsars that blink with such precise regularity; they are considered the most accurate natural clocks in the universe. As a result, scientists can watch for changes in a pulsar’s blinking that could indicate something happening in the space nearby. 

It was with this method that scientists began to identify the presence of alien planets orbiting these dense objects. In fact, the first planet outside Earth’s solar system ever found was orbiting a pulsar. 

Because pulsars are moving through space while also blinking a regular number of times per second, scientists can use many pulsars to calculate cosmic distances. The changing position of the pulsar means the light it emits takes more or less time to reach Earth. Thanks to the exquisite timing of the pulses, scientists have made some of the most accurate distance measurements of cosmic objects.

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The Arecibo Observatory in Puerto Rico has collapsed, after weeks of concern from scientists over the fate of what was once the world’s largest single-dish radio telescope.

The telescope was built in the early 1960s, with the intention of studying the ionised upper part of Earth’s atmosphere, the ionosphere. But it was soon being used as an all-purpose radio observatory.

Radio astronomy is a field within the larger discipline that observes objects in the Universe by studying them at radio frequencies. A number of cosmic phenomena such as pulsars – magnetised, rotating stars – show emission at radio wavelengths.

The observatory provided the first solid evidence for a type of object known as a neutron star. It was also used to identify the first example of a binary pulsar (two magnetised neutron stars orbiting around a common centre of mass), which earned its discoverers the Nobel Prize in Physics.

The telescope helped to make the first definitive detection of exoplanets, planetary bodies orbiting other stars, in 1992.

It has also been used to listen for signals from intelligent life elsewhere in the cosmos and to track near-Earth asteroids.

Over the years, the main dish appeared as a location in movies, including GoldenEye, Pierce Brosnan’s first outing as James Bond in 1995, and the 1997 science fiction drama Contact, starring Jodie Foster and Matthew McConaughey.

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K2 is located at 28251 ft above sea level, which makes it the second highest mountain in the world, after Mount Everest at 29029 ft. The location of K2 is between Baltistan in the Gilgit-Baltistan region of north Pakistan and the Dafdar Township in Taxkorgan Tajik of Xinjiang, China. K2 is also referred to as Mount Godwin-Austen in honour of Henry Godwin-Austen, an early explorer of the region. Although the name was rejected by the Royal Geographical Society, it is used on several maps and places. K2 is the sole 8000 m peak that has never been reached by anyone from its East Face or during winter time. Being situated towards the north, it is more prone to severe winters. It was George Bell, a climber on the 1953 American Expedition, named K2 as the Savage Mountain after its deadly nature, when he almost slipped from the climb. It is said that out of every four mountaineers who climb the mountain, one person dies. The story of how K2 got its name goes like this. In 1856, a British officer working for the Great Trigonometrical Survey of India reached a small mountain in Kashmir. There, his sight fell on two special peaks more than 200 km away in the Karakoram. He named them K1 and K2, the ‘K’ standing for Karakoram.

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Environmental advocacy groups such as Greenpeace have been appealing to the UN’s International Seabed Authority (ISA) against giving license to companies to carry out deep-sea mining. Highlighting that the industry is inadequately regulated in a report published last week, Greenpeace has drawn attention to the threats facing the deep-ocean ecosystem from deep-sea mining.

Mining carried out in the ocean floor is called deep-sea mining. It is done to retrieve mineral deposits from 1,400 to 3,700 metres below the ocean’s surface using hydraulic pumps.

Rising demand for metals such as copper, nickel, aluminium, manganese, zinc and lithium and the depletion of these metals from terrestrial deposits have resulted in a growing interest in deep-sea mining.

Sixteen international mining companies have contracts to explore the seabed for minerals in the Indian Ocean and the Pacific Ocean. They have already begun exploring the deep sea – assessing the size, extent of mineral deposits, composition, distribution, and economic value. Together, the ear-marked area for extraction is about 1.5 million km2 of international seabed.

Deep-sea mining particularly targets polymetallic nodules or active and extinct hydrothermal vents, which contain valuable metals. While hydrothermal vents are fissures on the seafloor from which geothermally heated water discharges, polymetallic nodules are potato-sized rock accretions that harbour commercially valuable metals like manganese, nickel, cobalt and copper.

Environmental impact

As with all mining operations, deep sea mining raises questions about its potential environmental impact.

The seafloor contains an extensive array of geological features. These remote areas support species that are uniquely adapted to harsh conditions. In fact, many of these species are unknown to science. The mining activity could pose danger to this pristine ecosystem.

Corals, sponges, sea urchins, starfish, jellyfish, squid, octopus, shrimp, and sea cucumbers are some of the known species that inhabit the depths of the oceans. Some of them are slow-growing, so a full recovery after mining could take thousands, if not millions of years – if a recovery is possible at all.

The sediment plumes and waste discharge from mining could trigger algae blooms and introduce toxic metals into marine food chains. This mining waste could also travel through the ocean and put many regions of the ocean under threat.

Light and noise pollution from the mining activity could disrupt a multitude of species attuned to living in the dark and those that use sound to communicate with other members of the species.

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