How the Eskdalemuir Observatory is used to monitor earthquakes, pollution and the Earth’s magnetic field

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Artist’s depiction of solar wind particles interacting with Earth’s magnetosphere. Sizes are not to scale. — from NASA

The Eskdalemuir Observatory began operation in the Scottish Borders in 1908 and its remote location allows for the monitoring of a variety of processes that affect people all around the globe. The original purpose of the observatory was the measurement of the geomagnetic field in the United Kingdom, but it is also currently used to track seismological activity and meteorological parameters.

With electric tramways spreading across London and interfering with the accuracy of the magnetic measurements at Kew Observatory, the National Physics Laboratory faced pressure to find a new location, at least 10 miles away from any sources of magnetic disturbances. Eventually, in 1903, five years after proposals for the tramways were announced, the site of Eskdalemuir was selected. The relocation was partly funded by a compensatory donation from the tramway company, and the Duke of Buccleuch offered a perpetual lease of the land. Eskdalemuir is well known for frequently being identified as the wettest or coldest location in the UK on given days, due to the elevation and exposure of the site, which is near the end of a long valley. …

How the NOvA experiment measures neutrino oscillations between detectors in different states

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The far detector at Ash River — from Fermilab

Neutrinos are subatomic particles which are invisible, have no electrical charge and are nearly massless. They are some of the most abundant particles in the Universe, however their properties mean that they are extremely difficult to detect, with roughly 100 trillion of them passing through our bodies every second. …

The struggles and triumphs of a mission to Ecuador to determine the shape of the Earth

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An oblate spheroid (left) and a prolate spheroid (right) — from Tomruen

In 1735, a team of French and Spanish scientists set sail on a mission organised by the French Academy of Sciences to settle a debate between Isaac Newton and René Descartes, and discover whether the circumference of the Earth was greater around the equator or around the poles. Under the sponsorship of the French minister of the navy, who understood that knowledge of the shape of the Earth was essential for navigating the oceans, the group led by French astronomer Louis Godin began the journey to Quito, now the capital of Ecuador.

The team landed on the Caribbean coast and crossed Panama overland, before continuing to sail through the Pacific to Ecuador. Such a long journey was necessary, because discovering the shape of the Earth required the measurement of a degree of latitude at two widely separated points. These measurements had already been taken in Paris, and the French government was sending another expedition to Lapland, close to the Arctic Circle, around the same time. Taking measurements close to the pole and the equator would provide the most conclusive results about the shape of the Earth. …

How SABRE aims to reveal the source of the DAMA collaboration’s mysterious signal

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The “Bullet Cluster” consists of two colliding galaxy clusters and provides some of the best evidence for the existence of dark matter — from NASA/CXC/M. Weiss

Dark matter makes up roughly 85% of the matter in the Universe. Although we are unable to see it, as it does not interact with light, observing its gravitational effects on objects such as galaxies and galaxy clusters provides us with evidence for its existence. Without the extra mass due to dark matter, entire galaxies would fly apart. Currently, the most popular candidate for dark matter is the Weakly Interacting Massive Particle (WIMP).

Since the 1990s, more and more experiments have joined the search for the WIMP, but the particles still evade detection. That is with the exception of the Italian DAMA collaboration, which, for the last decade, has been claiming to have found the elusive particle. …

How NASA’s Deep Space Network keeps contact with distant spacecraft

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70 m antenna at Goldstone, California — from Wikipedia Commons

After reading about how the Deep Space Network (DSN) will be used to communicate with the James Webb Space Telescope at the second Sun-Earth Lagrange point following its launch planned for 2021, I wanted to learn more about this worldwide network of facilities and how its three locations were chosen. The DSN consists of antennas at the Goldstone Communications Complex near Barstow, California, the Madrid Deep Space Communications Complex in Spain, and the Canberra Deep Space Communication Complex near the Australian capital. The three locations are spaced roughly 120° apart in longitude around the globe, which allows constant observation of spacecraft. …

How LIGO uses laser interferometry to detect gravitational waves

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The interferometer at the Hanford site — Courtesy Caltech/MIT/LIGO Laboratory

The Laser Interferometer Gravitational-Wave Observatory (LIGO) was designed to detect the cosmic gravitational waves predicted by Einstein’s General Theory of Relativity to propagate from accelerated masses. The experiment is funded by the U.S. National Science Foundation (who have so far invested roughly $1.1 billion in its construction and development) and run by the California Institute of Technology (Caltech) and the Massachusetts Institute of Technology (MIT).

LIGO consists of two widely separated observatories, which use the technique of laser interferometry to measure tiny ripples in spacetime (the three dimensions of space plus the single dimension of time) predicted to be caused by gravitational waves. The two identical interferometers each have two 4 km arms at right angles to each other. When a laser beam enters an interferometer, it encounters a beamsplitter at the point where the two arms meet. This means that part of the beam is reflected down one of the arms, while the rest of the beam is transmitted along the other. Each arm contains a mirror at the far end, and after several trips up and down the arms, the beams are recombined. …

How the James Webb Space Telescope will observe the early universe from its home at the second Lagrange point

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James Webb Space Telescope Mural Image — from Northrop Grumman

The James Webb Space Telescope, often referred to as “Webb”, is a space-based observatory, named after the second administrator of NASA, that aims to expand upon the discoveries made by the Hubble Space Telescope. It will have a much larger primary mirror than Hubble, allowing it to collect more light, requiring an unfolding mirror made of hexagonal segments that can fit into the rocket used to launch the telescope. Webb is being developed by NASA, with contributions from the European and Canadian Space Agencies.

How the unique properties of the South Pole allow the IceCube Neutrino Observatory to detect the elusive particles

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The surface facility for the IceCube experiment — from IceCube Neutrino Observatory

Neutrinos are invisible, electrically neutral and nearly massless subatomic particles. Since they travel through the Universe at close to the speed of light without being absorbed or deflected by cosmic objects, neutrinos can provide us with information to further our understanding of their mysterious origins in processes such as supernovae (the explosive death of a star) and black holes. However, these properties also make neutrinos extremely difficult to detect, with roughly 100 trillion of them passing through our bodies every second, so how can we hope to find these elusive particles?

One experiment which searches for neutrinos is the IceCube Neutrino Observatory at the Amundsen-Scott South Pole Station in Antarctica. The experiment covers a volume of one cubic kilometre and cost $279 million USD, which was mainly provided by the US National Science Foundation. The IceCube Collaboration consists of around 300 scientists from 12 countries. …

How Eratosthenes calculated his surprisingly accurate value for the Earth’s circumference

A well at Kom Ombo, 50 km north of Syene — from isawnyu

After writing about some of the most exciting current and future experiments around the world, I decided to look all the way back to around 240 B.C., when Eratosthenes became the first person to measure the circumference of the Earth. Although by this time many Greeks believed that the Earth was round, they had found no way of measuring its size.

That is until Eratosthenes, who had been appointed chief librarian of the library of Alexandria, heard from travellers about a well in Syene (now Aswan, Egypt), which was unobstructed by shadows at local noon on the summer solstice, indicating that the Sun was directly overhead. …

Constructing the Square Kilometre Array in South Africa and Australia

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Artist’s composition of the entire SKA1 array — from SKA Organisation/Swinburne Astronomy Productions

The Square Kilometre Array (SKA) is a proposed international radio telescope project. Rather than being a single telescope, the SKA is a collection of different antennas working together, known as an array, which would have a total collecting area of over 1 km². The size of the array would make the SKA 50 times more powerful than other radio instruments, allowing it to detect very weak radio signals emitted in the first billion years of the Universe.

This will allow the SKA to explore questions about the evolution of galaxies, the nature of dark energy, the source of giant magnetic fields in space, and the formation of the first stars and black holes. The versatility and sensitivity of the SKA also give this project the potential to make unexpected discoveries. The telescope will produce around 160 terabytes (equivalent to 35,000 DVDs) per second, so the SKA project is collaborating with companies such as IBM to create advances in Big Data science. …


Anna Harriet

Physics master’s graduate. Currently making plans for future research and travel.

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