Tag: Astronomy

Space Sunday: of rockets, rovers and impacts

Posted on by Inara Pey
Blue Origin's New Shephard lifts-off on Saturday, April 2nd on a successful sub-orbital test flight which saw both capsule and propulsion module successfully recovered
Blue Origin’s New Shephard lifts-off on Saturday, April 2nd on a successful sub-orbital test flight which saw both capsule and propulsion module successfully recovered

Blue Origin, established by  Amazon founder Jeff Bezos, scored a three-for-three with launches and landings of their sub-orbital New Shephard launch vehicle.

Intended to offer passengers the opportunity to experience the microgravity of space, New Shephard is a two stage vehicle comprising the capsule unit which will eventually carry  6 people to the each of space, and a rocket stage simply called the “propulsion module”. Both are designed to be fully re-usable in order to reduce the overall cost of launch operations.

The Blue Origin propulsion module just a couple of seconds from touch down on April 2nd, 2016 (image: Blue Origins)
The Blue Origin propulsion module just a couple of seconds from touch down on April 2nd, 2016 (image: Blue Origins)

Having first flown on November 23rd, 2015, when the capsule unit reached an altitude of 100.5 km (63 mi) before parachuting back to a soft landing and the propulsion module made a powered descent and landing, the April 2nd, 2016, marked the third successful flight for both capsule and propulsion module, the latter now having been used for all three successful flights in November 2015, January 2016 and April 2016.

During the flight, the capsule – which was carrying a small science payload – reached a maximum altitude of 103.4 km (64.4 mi) before making a return to Earth under its parachutes, while the propulsion module steered its way back to the launch site to make a powered landing.

Nor was this a run-of-the-mill return for the propulsion module, as a the ascent / descent engine was re-lit at a much higher altitude that is expected during operational flights, at around 1,107 metres (3,600 ft), in a manoeuvre designed to further test the engine’s reliability and the wear and tear it might suffer during a flight. Understanding both of these factors will help Blue Origin better identify the overall costs involved in refurbishing rocket and engines between flights.

The New Shephard capsule, whilst primarily intended to fly people on sub-orbital flights, can also be used for science research, as demonstrated in this flight, which saw the capsule carry the Box of Rocks experiment from the Southwest Research Institute, designed to explore how rocky debris settles in microgravity, and the University of Central Florida’s Collisions into Dust experiment, which aims to better understand how large bodies interacted with dust in the early Solar System.

The New Shephard capsule being recovered following its parachute landing (image: Blue Origin)
The New Shephard capsule being recovered following its parachute landing (image: Blue Origin)

While Blue Origin appear to be slightly ahead of SpaceX in terms of launching and recovering their rockets, it’s important to remember that the current New Shephard vehicle and the SpaceX Falcon 1.1 are very different beasts. Not only is the latter some 3 times bigger than New Shepard, the first stage of the vehicle flies much higher and faster than the Blue Origin vehicle, both of which make returning the first stage of the booster to a landing site to make a safe touchdown far more of a technical challenge.

That said, the sub-orbital capabilities of New Shephard are only one phase of Blue Origin’s plans. With the vehicle expected to commence crewed test flights in 2017 and offer sub-orbital tourist flights from 2018, the company plan to gradually uprate the vehicle to a point were it will also be able to undertake orbital launches and still be recovered.

Walking with Rovers

NASA is continuing to ramp public interest in Mars, with a new public outreach programme set to begin in summer 2016.

Destination: Mars builds on the ongoing cooperative work between the space agency and Microsoft in developing applications and opportunities for the Miscrosoft HoloLens system. As I’ve previously reported, NASA is already using the HoloLen aboard the International Space Station, and have also developed a means for members of the Curiosity science team put themselves “on” Mars using the HoloLens and data / images returned by the rover.

It is in the latter capacity that Destination: Mars is designed to work, offering the public, using the mixed reality capabilities of the HoloLens to “visit” Mars.

Apollo 11 Lunar Module Pilot and second man on the Moon, Edwin "Buzz" Aldrin, acts as a virtual host for Destination: Mars
Apollo 11 Lunar Module Pilot and second man on the Moon, Edwin “Buzz” Aldrin, acts as a virtual host for Destination: Mars

Continue reading “Space Sunday: of rockets, rovers and impacts” →

Space Sunday: of ice and salts, aurorae, and mountains

Posted on by Inara Pey
A true colour image returned by the Dawn space probe of one of the bright "spots" in Occator crater on Ceres, revealing what might be a cryo-volcano
A true colour image returned by the Dawn space probe of one of the bright “spots” in Occator crater on Ceres, revealing what might be a cryovolcano (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

The science team behind the joint NASA / ESA Dawn mission has released the most stunning high-resolution images yet seen of Ceres, one of the solar system’s three “protoplanets” located in the asteroid belt between the orbits of Mars and Jupiter.

The Dawn spacecraft has been mapping Ceres for also a year, operating at its lowest altitude above the tiny world since December 2015. During the course of the year, the images and data it has returned have, alongside information sent to us about Pluto and Charon by the New Horizons mission, caused planetary scientists to start seriously reconsidering all they thought they understood about minor planetary bodies in the solar system.

However, one thing everyone has been waiting for has been to see high-resolution images of Occator crater and the strange bright spots within it which have been the cause of so much interest and speculation, ever since they were first imaged by the Hubble Space Telescope.

A false-colour image showing the main peak in Occator crater with the small bright spots off to the right
A false-colour image showing the main peak in Occator crater with the small bright spots off to the right (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

While the vehicle may have commenced its most detailed mapping orbit of Ceres in December, due to the complexities of Dawn’s orbit around the tiny world, it was not until relatively recently that it was able to overfly the 92 km (57 mi) diameter Occator and capture images of what lay within it, and these images were released on March 22nd, as a part of a science briefing given at the 7th annual Lunar and Planetary Science Conference in Texas.

Taken from an altitude of just 385 kilometres (240 miles) above the crater, the images reveal a huge dome-like structure with a dimpled top forming the brightest of the “spots” in Occator. It looks for all the world like a volcano, prompting speculation that it might be what is called a “cryovolcano”. The theory here being that Ceres may contain significant quantities of volatiles (ices), which are gently heated by the dwarf planet’s interior, causing them to erupt through the surface layer, the deposits they leave behind slowly building up the volcano-like dome.

A false colour elliptical map of Ceres showing that Occator (just right of centre) is not the only bright spot on the tiny planetoid others, mostly associated with young (around 70-150 million years old) craters
A false colour elliptical map of Ceres showing that Occator (just right of centre) is not the only bright spot on the tiny planetoid others, mostly associated with young (around 70-150 million years old) craters (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

However, this is not he only theory on what might be happening. Spectral observations show that the light patches found in Occator and elsewhere are consistent with a magnesium sulphate called hexahydrite, which resembles Epsom salts here on Earth. Thus, an alternative theory is that impacts in places like Occator expose the salt-rich ices trapped in the crust to the vacuum of space. This causes the ice to sublimate (vaporise), leaving the salt behind.

Commenting on the two the two theories, Ralf Jaumann, planetary scientist and Dawn co-investigator at the German Aerospace Center (DLR) said, “Before Dawn began its intensive observations of Ceres last year, Occator Crater looked to be one large bright area. Now, with the latest close views, we can see complex features that provide new mysteries to investigate. The intricate geometry of the crater interior suggests geologic activity in the recent past, but we will need to complete detailed geologic mapping of the crater in order to test hypotheses for its formation.”

In the interim, NASA has released a new video summarising Dawn’s investigations of Ceres.

Cygnus Rendezvous with ISS

March 22nd saw the latest Orbital ATK Cygnus resupply vehicle lifted-off from Space Launch Complex 41 on Cape Canaveral Air Force Station, Florida in a spectacular night-time launch beneath a full Moon.

The automated vehicle, carrying 3.5 tonnes of supplies and equipment up to the International Space Station, made a flawless ascent into the Florida sky, the clear weather and moonlight offer some extraordinary opportunities for photographers, as shown in the image below, taken by Alex Polimeni for Spaceflight Now.

Long exposure photograph shows the trail of the Atlas V launch vehicle as it carries the Cygnus OA6 vehicle "Rick Husband" into orbit on March 22nd, 2016. In the foreground is the world famous Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Centre (credit: Alex Polimeni / Spaceflight Now)
Long exposure photograph shows the trail of the Atlas V launch vehicle as it carries the Cygnus OA6 vehicle “Rick Husband” into orbit on March 22nd, 2016. In the foreground is the world-famous Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Centre (credit: Alex Polimeni / Spaceflight Now)

Continue reading “Space Sunday: of ice and salts, aurorae, and mountains” →

Space Sunday: a Martian sandwich

Posted on by Inara Pey
ExoMars unofficial logo
ExoMars unofficial logo (credit: DLR)

If all goes according to plan, at 09:31 GMT on Monday March 14th, a Russian Proton launcher is scheduled to lift-off from the Baikonaur Cosmodrome Kazakhstan, sending the first part of the European ExoMars mission on its way to Mars.

With its suite of high-tech instruments, the Trace Gas Orbiter (TGO) should arrive at the Red Planet on October 19th, 2016, after a journey of 496 million kilometres (308 million miles). While Its main mission is to photograph the Red Planet and analyse its air, the TGO is also carrying a small Mars lander, dubbed Schiaparelli, after the man who first thought he saw canali (as in “groves” or “channels”) on Mars in the 1870s, and thus inadvertently sparked the entire “canals on Mars mythos.

March 11th 2016: the Proton rocket with TGO and EDM on-board is hoisted to the vertical position at its launch pad in the Baikonaur Cosmodrome, Kazakhstan
March 11th 2016: the Proton rocket with TGO and EDM on-board is hoisted to the vertical position at its launch pad in the Baikonaur Cosmodrome, Kazakhstan

A key goal for the TGO mission is to analyse the methane gas which has frequently been detected on Mars by various missions. Methane can either be generated in a biological process, such as microbes decomposing organic matter, or geological ones involving chemical processes in hot liquid water under the surface. However, it also tends to be broken down by  ultraviolet radiation within a few hundred years, so for it to be detected at all on Mars means whatever is producing it is liable to be an active process, and identifying what that process actually is – organic or inorganic – is a crucial part of furthering our understanding of Mars, and could have major ramifications for future missions.

“TGO will be like a big nose in space,” according to Jorge Vago, an ExoMars project scientist. “It will analyse Mars’ methane in more detail than any previous mission and try to determine its origins.”

In addition, TGO will monitor seasonal changes in Mars’ atmospheric composition and temperature in order to create and refine detailed models of the Martian atmosphere. Its instruments will also map the subsurface hydrogen to a depth of a metre, with improved spatial resolution compared with previous measurements. This could reveal deposits of water-ice hidden just below the surface, which, along with locations identified as sources of the trace gases, could influence the choice of landing sites of future missions.

TGO’s findings will also be used to help plan the second phase of the ExoMars mission, due to fly in 2018 (or possibly 2020 due to budget concerns). This will be a solar-powered rover unit, slightly larger than NASA’s MER rovers, Spirit and Opportunity. It’s also a rover with a long gestation period, having been under development for almost 20 years.

Originally designed to be a much bigger vehicle, ExoMars was going to be a joint ESA / NASA undertaking, with ESA supplying the rover and NASA some of the science instruments and the launch vehicle. However, in 2012, NASA arbitrarily withdrew from the project, forcing Europe to go back to the drawing board and seek Russian support for the mission (Russia is supplying the launch vehicle and the landing platform for the rover, as well as some of the science instruments carried aboard both the rover and TGO).

Artist's impression of the ExoMars rover rolling off of its landing platform (credit: ESA)
Artist’s impression of the ExoMars rover rolling off of its landing platform (credit: ESA)

Unlike NASA’s Curiosity mission (but like NASA’s upcoming Mars 2020 mission), ExoMars is intended to directly seek out evidence of current or past microbial life on Mars. As such, the findings from TGO could be key in the selection of the final landing site for the rover. In addition, TGO will also act as the primary communications relay between the rover and Earth.

It is also as a communications relay that TGO will support the Schiaparelli lander. Officially named the Entry, Descent and Landing Demonstrator Module (EDM), Schiaparelli is intended to help ESA in developing the technology for landing on the surface of Mars with a controlled landing orientation and touchdown velocity. Obviously, a safe entry, descent and controlled landing capability is crucial to the success of the ExoMars rover mission, and Schiaparelli will help in determining the final design and development requirements for the rover’s landing systems.

The Schiaparelli EDM
The Schiaparelli EDM

Continue reading “Space Sunday: a Martian sandwich” →

Space Sunday: Martian “coral”, Planet Nine and Dream Chasers

Posted on by Inara Pey
The MER rovers first arrived on Mars at the start of 2004. One, Opportunity, is still operating today
The MER rovers first arrived on Mars at the start of 2004. One, Opportunity, is still operating today (credit: NASA / JPL)

Spirit, one of NASA’s two solar-powered Mars Exploration Rover (MER) missions, may have ceased communications with Earth on March 22nd, 2010 and the mission declared over on May 24th, 2011, but its science legacy lives on.

Originally designed with a 90-day primary mission duration, Spirit massively exceeded this, ranging across Mars for a distance of 7.73 kilometres (4.8 mi) over 1,944 days of mobile operations before becoming bogged down in a sand trap on May 1st, 2009, almost 5.5 years after it had arrived on Mars, after which it operated as a stationary research programme for a further 751 days.

During its mobile period, Spirit explored a small rocky plateau dubbed “Home Plate” in 2007 / 2008. Whilst exploring the rock, the rover imaged several peculiar small rock formations resembling cauliflower or coral.  Analysis by the rover’s Mini-Thermal Emission Spectrometer (Mini-TES) revealed the formations to be almost pure silica (SiO2), a mineral associated with volcanic environments.

Silica is formed when water (rain or snow) seeps underground and comes into contact with rocks heated from below by magma. Itself super-heated by the rocks, the water is vaporised and rises back through the ground, dissolving silica and other minerals as it does so, which it deposits around the vents or fumaroles it uses to escape back into the atmosphere.

the "cauliflower" or "coral" formations imaged by MER rover Spirit around the "home Plate" plateau in 2008
the “cauliflower” or “coral” formations imaged by MER rover Spirit around the “home Plate” plateau in 2008 (credit: NASA / JPL)

Warm, rich in silica and minerals, on Earth these fumaroles and vents become havens for bacterial life which is known for creating curious bulbous and branching shapes in silica formations here on Earth which are strikingly similar to those imaged by Spirit. Such is the similarity, that planetary geologist Steven Ruff and geology professor Jack Farmer, both from Arizona State University, have been carrying out detailed studies in the high Atacama Desert, regarded as the most arid non-polar region on Earth, harbouring conditions thought to be very similar to those of ancient Mars.

In particular, they have been investigating the remote geyser fields of El Tatio, some 4.3 km  above mean sea level in an environment which has much in common with the Gusev Crater region of Mars, where “Home Plate” resides. This includes being exposed to high levels of ultraviolet light from the sun and extreme temperatures.  Their investigations revealed forms they call “micro-digitate silica structures” which are both remarkably similar to the formations on Mars, and to those found around fumaroles and vents at lower altitudes here on Earth which are formed by bacteria.

A comparison between images of the formations found on Mars by the MER Spirit (top right), and those images by Ruff and Foster in El titio, Atacama Desert
A comparison between images of the formations found on Mars by the MER Spirit (top right), and those imaged by Ruff and Foster in El Tatio, Atacama Desert (credit: S. Ruff, Arizona State University)

While the pair have yet to come up with definitive evidence that the El Tatio formations are the result of microbial activity, they believe the objects may be “micro-stromatolites”.  Nornally of a much larger size, stromatolites are formed by bacteria “cementing” mineral grains together to form a thin layer. Over time, these layers accumulate one over the last, forming a laminar mound or rock. The oldest stromatolites on Earth are estimated to be some 3.5 billion years old, a time when both Earth an Mars may have shared much closer atmospheric and geological similarities. So, if the formations found at El Tatio do prove to be the result of bacterial activity, then it offers a hypothesis that the formations on Mars may also have been the result of bacterial activity.

Dream Chaser: the Dream is Alive

In January, I wrote about NASA’s surprise decision to award an extended contract for uncrewed resupply missions to  the International Space Station to both of the existing contract holders, SpaceX and Orbital ATK, and to Sierra Nevada Corporation, who will use an uncrewed variant of their Dream Chaser space plane.  At the time I wrote that update, reader Devin  Vaughn indicated an interest in learning more about Dream Chaser, which has an interesting heritage.

As I noted at the time, the vehicle had been one of four private sector contenders to fulfil the role of “space taxi”, ferrying up to 6 at a time from US soil to the ISS. The idea being that by spinning-out the ISS crewed flights to the private sector (with financial support from NASA), the US agency could focus its manned space flight development programme solely on the Orion / SLS programme, which is intended to form the nucleus of US (and possibly international) crewed mission ventures well beyond Earth orbit.

Dream Chaser was unique among the commercial crew transportation proposals as it was based on a "lifting body" design , allowing to re-enter the Earth's atmosphere and glide to a landing on a conventional runway - aspects which still make it a very flexible vehicle
Dream Chaser was unique among the commercial crew transportation proposals as it was based on a “lifting body” design , allowing to re-enter the Earth’s atmosphere and glide to a landing on a conventional runway – aspects which still make it a very flexible vehicle (credit: SNC)

Dream Chaser ultimately wasn’t selected for the crewed mission contract – which caused some friction between Sierra Nevada Corporation and NASA when it was announced in 2014 – but the US space agency continued to work with SNC to help develop the vehicle,  with the Dream Chaser Cargo variant being the result – although SNC has not given up on developed the crewed version of the vehicle.

Dream Chaser Cargo is designed to fly up to 5 tonnes of cargo to / from orbit. This can be both pressurised and unpressurised material, and the vehicle includes the ability for unpressurised cargo to be directly transferred from its cargo module to the exterior of the space station should this be required. As with the original crewed variant, Dream Chaser Cargo will launch atop a rocket, but return to earth to make a conventional runway landing, the latter greatly speeding up the transfer of returned cargo (e.g. science experiments material, etc.) from the vehicle to its intended destination.

Continue reading “Space Sunday: Martian “coral”, Planet Nine and Dream Chasers” →

Space update: Charon’s ocean, Virgin’s spaceplane and your art in space

Posted on by Inara Pey

new-horizonThe Pluto – Charon system is, as I’ve reported through various Space Sunday reports, turning out to be far more remarkable a place than scientists ever imagined. While NASA’s New Horizons space vehicle, which zapped past both Pluto and Charon during its closest approach to both on July 14th, 2015.

On February 18th, NASA revealed the most recent surprise to be revealed by New Horizons: Charon may have once had a subsurface ocean that has long since frozen and expanded, pushing outward and causing the moon’s surface to stretch and fracture on a massive scale.

The side of Charon imaged by NASA’s probe is characterised by a system of “pull apart” tectonic faults, which are expressed as ridges, scarps and valleys—the latter sometimes reaching more than 6.5 kilometres (4 miles) deep. Charon’s tectonic landscape shows that, somehow, the moon expanded in its past, fracturing as it stretched.

The outer layer of Charon is primarily water ice. This layer was kept warm when the tiny world / moon was young by heat provided through the decay of radioactive elements, as well as Charon’s own internal heat of formation. Scientists say Charon could have been warm enough to cause the water ice to melt deep down, creating a subsurface ocean. However, as it cooled over time, this ocean would have frozen and expanded (as happens when water freezes), lifting the outermost layers of the moon and producing the massive chasms we see today.

A close-up of the canyons on Charon, Pluto's big moon, taken by New Horizons during its close approach to the Pluto system last July. Multiple views taken by New Horizons as it passed by Charon allow stereo measurements of topography, shown in the color-coded version of the image. The scale bar indicates relative elevation. Credits: NASA/JHUAPL/SwRI
A close-up of the canyons on Charon taken by New Horizons from a distance of 78,700 km (48,00 mi) and around 1 hour and 40 minutes before the spacecraft reach the point of its closest approach to Charon on July 14th, 2015. Multiple views taken by New Horizons as it passed by Charon allow stereo measurements of topography, shown in the colour-coded version of the image. The scale bar indicates relative elevation (image: NASA / JHU/ APL / SwRI

In an image gathered by the Long-Range Reconnaissance Imager (LORRI) in July 2015 and release by NASA on February 18th, reveals a vast equatorial belt of chasms on Charon. This network is around 1,800 km (1,100 mi) long and in places is 7.5 km (4.5 mi) deep. By comparison, the Grand Canyon is 446 km (277 mi) long and around 1.6 km (1 mile) deep.

The inset images on the picture show one section of the network of chasms, informally named “Serenity Chasma”, with a matching colour-coded topography map.  Measurements of “Serenity Chasma” strongly suggest Charon’s water ice layer may have been at least partially liquid in its early history, and has since refrozen.

SpaceShipTwo Unveiled

SpaceShipTwo VSS Unity, rolled-out on February 19th, 2016
SpaceShipTwo VSS Unity, rolled-out on February 19th, 2016 (image: Virgin Galactic)

Virgin Galactic, Sir Richard Branson’s private venture company which is aiming to become the world’s first commercial space line, offering fare-paying passengers sub-orbital flights into space. rolled out it new SpaceshipTwo vehicle on Friday February 19th.

The event came more than a year after the loss of the first SpaceShipTwo craft, the VSS Enterprise, in a tragic accident in which the craft broke up in mid-air on October 31st, 2014, killing co-pilot Michael Alsbury, and seriously injuring pilot Peter Siebold. At the time of the accident, several other figures involved in private sector space efforts were quick to point to Virgin Galactic’s use of nitrous-oxide as a vehicle propellant and to suggest corner-cutting by the company as causes of the accident.

However, after investigating the incident, the US National Safety Transportation Board (NTSB) drew the conclusion that the incident was largely the result of pilot error: the “feathering” mechanism designed to be used at the edge of space to allow the vehicle to gently re-enter the denser layers of Earth’s atmosphere was inadvertently deployed by co-pilot Alsbury, resulting in the immediate aerodynamic destabilisation and break-up of the vehicle. As a result of these findings, and as a part of a series of improvements made to the vehicle, the new SpaceShipTwo  includes a locking mechanism designed to prevent the feathering system being deployed in error.

VSS Unity is rolled out in a ceremony which saw it christened by Professor Stephen Hawking and Sir Richard Branson's year-old granddaughter
VSS Unity is rolled out in a ceremony which saw it christened by Professor Stephen Hawking and Sir Richard Branson’s year-old granddaughter (image: Virgin Galactic)

The new vehicle, christened VSS Unity by Professional Stephen Hawking (assisted by Branson’s year-old granddaughter), was rolled-out at a special media event held at  Virgin Galactic’s operations and flight facilities in the Mojave Desert, California. It marks the start of a long programme to get the vehicle to a point where it is ready to undertake its first powered flight.

This programme will include a series of ground tests of various vehicle systems, followed by taxi tests on the runway at the Mojave Air and Space Port. after these will come “captive carry” flights, where SpaceShipTwo remains attached to its WhiteKnightTwo carrier aircraft, then unpowered glide flights before the first in a series of powered test flights. While this test programme is not expected to be as protracted as the flight evaluation programme undertaken by VSS Enterprise prior to its crash, iy does mean that the company is not ready to provide any suggested dates by which fare-paying flights might commence.

Continue reading “Space update: Charon’s ocean, Virgin’s spaceplane and your art in space” →

Space Sunday: of Einstein, waves, landers and honours

Posted on by Inara Pey
The LIGO observatory, Hanford, Washington State
The LIGO observatory, Hanford, Washington State (source: LIGO)

Thursday, February 11th saw the announcement of the first direct detection of gravitational waves (not to be confused with “gravity waves”, as some in the media initially took to calling them, but which are something else entirely*), which are ripples in the fabric of space-time whose existence was first proposed by Albert Einstein, in 1916.

The detection came about partly as happenstance, in that the Large Interferometer Gravitational Wave Observatory (LIGO), a world-wide operation established in 1992 and involving 900 scientists from 80 institutions in 15 countries. However, the detectors in use up until recently had failed to provide direct evidence of gravitational waves.

Albert Einstein in 1916, when he was formulating his General Theory of Relativity
Albert Einstein in 1916, when he was formulating his General Theory of Relativity (source: Wikipedia)

Enter the National Science Foundation in the United States.  Over the last five years, they have funded the development and construction of two “Advanced LIGO” detectors, themselves massive feats of technology and engineering, located 3,000 km apart in the United States. One resides Livingston, Louisiana, and the other in Hanford, Washington State.

These detectors started running in February2015, in what was called an “engineering mode”. However, in September 2015 work started on running them up to full operational status when, and completely unexpectedly and within milliseconds of one another, both appeared to detect gravitational passing through them.

The odds of such an event occurring almost precisely at the time when the detectors were starting to do the work for which they have been designed would seem to be – and no pun intended – astronomical. As a result the LIGO investigators wanted to be sure of what had just happened and verify what they had apparently detected; hence why the news was only released on February 11th, 2016, several months after the actual detection had been made.

Since the initial detection, the LIGO teams have deduced the gravitational waves were created by two black holes, each barely 150km across,  but each travelling at around half the speed of light and massing around 30 times as much as our on Sun, spinning around one another and merging together some 1.3 billion light years away. As such, the detection marked two things: the first direct proof of gravitational waves and the conformation of a another theory: that black holes can meet and coalesce to create much larger black holes.

But what are “gravitational waves”, and why are they important?

Predicted over a century ago by Einstein in his theory of general relativity, gravitational waves are at their most basic, ripples in spacetime, generated by the acceleration or deceleration of massive objects in the cosmos. So, for example, if a star goes supernova or two black holes collide or if two super-massive neutron stars orbit closely about one another, they will distort spacetime, creating ripples which propagate outwards from their source, like ripples across the surface of a pond. The problem has been that these ripples are incredibly hard to detect, although the proof that they may well exist has been available since 1974.

It was in that year, two decades after Einstein’s passing, that astronomers at the Arecibo Radio Observatory in Puerto Rico discovered a binary pulsar (two rapidly rotating neutron stars orbiting one another). Over the ensuing years, astronomers measured how the period of the stars’ orbits changed over time. By 1982 it had been determined the stars were getting closer to each other at exactly the rate Einstein’s  of general theory relativity predicted would be required for the generation of gravitational waves. In the 40 years since its discovery, the system has continued to fit so precisely with the theory, and astronomers have had little doubt it is emitting gravitational waves.

The moment of detection: September 14th, 2015
The moment of detection: September 14th, 2015 (source: BBC News)

The LIGO detection however, provides the first direct  evidence of gravitational waves, and with it comes the ability to see the universe in a totally new way.

“It’s like Galileo pointing the telescope for the first time at the sky,” LIGO team member Vassiliki  Kalogera, a professor of physics and astronomy at Northwestern University in Illinois, said. “You’re opening your eyes — in this case, our ears — to a new set of signals from the universe that our previous technologies did not allow us to receive, study and learn from.”

Just as we’re able to study the universe in various wavelengths of light, using them to reveal things we otherwise would not be able to see, so gravitational waves will allow us to see the more of the dynamics in cosmic events which have so far remained hidden from us. We would in theory be able to see precisely what is happening in the heart of a supernova for example, and be able to detect the collisions and mergers of black holes, and more. So gravitational waves offer us a further means to increase our understanding of the cosmos.

(*In case you were wondering, gravity waves are physical perturbations driven by the restoring force of gravity in a planetary environment; that is, they are specific to planetary atmospheres and bodies of water, not cosmological events.)

Continue reading “Space Sunday: of Einstein, waves, landers and honours” →