Posted on by Matt Williams

An Artificial Intelligence Just Found 56 New Gravitational Lenses

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

Gravitational lenses are an important tool for astronomers seeking to study the most distant objects in the Universe. This technique involves using a massive cluster of matter (usually a galaxy or cluster) between a distant light source and an observer to better see light coming from that source. In an effect that was predicted by Einstein’s Theory of General Relativity, this allows astronomers to see objects that might otherwise be obscured.

Recently, a group of European astronomers developed a method for finding gravitational lenses in enormous piles of data. Using the same artificial intelligence algorithms that Google, Facebook and Tesla have used for their purposes, they were able to find 56 new gravitational lensing candidates from a massive astronomical survey. This method could eliminate the need for astronomers to conduct visual inspections of astronomical images.

The study which describes their research, titled “Finding strong gravitational lenses in the Kilo Degree Survey with Convolutional Neural Networks“, recently appeared in the Monthly Notices of the Royal Astronomical Society. Led by Carlo Enrico Petrillo of the Kapteyn Astronomical Institute, the team also included members of the National Institute for Astrophysics (INAF), the Argelander-Institute for Astronomy (AIfA) and the University of Naples.

The notable gravitational lens known as the Cosmic Horseshoe is found in Leo. Credit: NASA/ESA/Hubble

While useful to astronomers, gravitational lenses are a pain to find. Ordinarily, this would consist of astronomers sorting through thousands of images snapped by telescopes and observatories. While academic institutions are able to rely on amateur astronomers and citizen astronomers like never before, there is imply no way to keep up with millions of images that are being regularly captured by instruments around the world.

To address this, Dr. Petrillo and his colleagues turned to what are known as “Convulutional Neural Networks” (CNN), a type of machine-learning algorithm that mines data for specific patterns. While Google used these same neural networks to win a match of Go against the world champion, Facebook uses them to recognize things in images posted on its site, and Tesla has been using them to develop self-driving cars.

As Petrillo explained in a recent press article from the Netherlands Research School for Astronomy:

“This is the first time a convolutional neural network has been used to find peculiar objects in an astronomical survey. I think it will become the norm since future astronomical surveys will produce an enormous quantity of data which will be necessary to inspect. We don’t have enough astronomers to cope with this.”

The team then applied these neural networks to data derived from the Kilo-Degree Survey (KiDS). This project relies on the VLT Survey Telescope (VST) at the ESO’s Paranal Observatory in Chile to map 1500 square degrees of the southern night sky. This data set consisted of 21,789 color images collected by the VST’s OmegaCAM, a multiband instrument developed by a consortium of European scientist in conjunction with the ESO.

A sample of the handmade photos of gravitational lenses that the astronomers used to train their neural network. Credit: Enrico Petrillo/Rijksuniversiteit Groningen

These images all contained examples of Luminous Red Galaxies (LRGs), three of which wee known to be gravitational lenses. Initially, the neural network found 761 gravitational lens candidates within this sample. After inspecting these candidates visually, the team was able to narrow the list down to 56 lenses. These still need to be confirmed by space telescopes in the future, but the results were quite positive.

As they indicate in their study, such a neural network, when applied to larger data sets, could reveal hundreds or even thousands of new lenses:

“A conservative estimate based on our results shows that with our proposed method it should be possible to find ?100 massive LRG-galaxy lenses at z ~> 0.4 in KiDS when completed. In the most optimistic scenario this number can grow considerably (to maximally ? 2400 lenses), when widening the colour-magnitude selection and training the CNN to recognize smaller image-separation lens systems.”

In addition, the neural network rediscovered two of the known lenses in the data set, but missed the third one. However, this was due to the fact that this lens was particularly small and the neural network was not trained to detect lenses of this size. In the future, the researchers hope to correct for this by training their neural network to notice smaller lenses and rejects false positives.

But of course, the ultimate goal here is to remove the need for visual inspection entirely. In so doing, astronomers would be freed up from having to do grunt work, and could dedicate more time towards the process of discovery. In much the same way, machine learning algorithms could be used to search through astronomical data for signals of gravitational waves and exoplanets.

Much like how other industries are seeking to make sense out of terabytes of consumer or other types of “big data”, the field astrophysics and cosmology could come to rely on artificial intelligence to find the patterns in a Universe of raw data. And the payoff is likely to be nothing less than an accelerated process of discovery.

Further Reading: Netherlands Research School for Astronomy , MNRAS

 

Posted on by Matt Williams

Astronomers Spot Hellish World with Titanium in its Atmosphere

Artist's impression showing the exoplanet WASP-19b, in which atmosphere astronomers detected titanium oxide for the first time. Credit: ESO

The hunt for exoplanets has turned up many fascinating case studies. For example, surveys have turned up many “Hot Jupiters”, gas giants that are similar in size to Jupiter but orbit very close to their suns. This particular type of exoplanet has been a source of interest to astronomers, mainly because their existence challenges conventional thinking about where gas giants can exist in a star system.

Hence why an international team led by researchers from the European Southern Observatory (ESO) used the Very Large Telescope (VLT) to get a better look at WASP-19b, a Hot Jupiter located 815 light-years from Earth. In the course of these observations, they noticed that the planet’s atmosphere contained traces of titanium oxide, making this the first time that this compound has been detected in the atmosphere of a gas giant.

The study which describes their findings, titled “Detection of titanium oxide in the atmosphere of a hot Jupiter“, recently appeared in the science journal Nature. Led by Elyar Sedaghati – a recent graduate from the Technical University of Berlin and a fellow at the European Southern Observatory – the team used data collected by the VLT array over the course of a year to study WASP-19b.

Like all Hot Jupiters, WASP-19b has about the same mass as Jupiter and orbits very close to its sun. In fact, its orbital period is so short  – just 19 hours – that temperatures in its atmosphere are estimated to reach as high as 2273 K (2000 °C; 3632 °F). That’s over four times as hot as Venus, where temperatures are hot enough to melt lead! In fact, temperatures on WASP-19b are hot enough to melt silicate minerals and platinum!

The study relied on the FOcal Reducer/low dispersion Spectrograph 2 (FORS2) instrument on the VLT, a multi-mode optical instrument capable of conducting imaging, spectroscopy and the study of polarized light (polarimetry). Using FORS2, the team observing the planet as it passed in front of its star (aka. made a transit), which revealed valuable spectra from its atmosphere.

After carefully analyzing the light that passed through its hazy clouds, the team was surprised to find trace amounts of titanium oxide (as well as sodium and water). As Elyar Sedaghati, who spent 2 years as a student with the ESO to work on this project, said of the discovery in an ES press release:

“Detecting such molecules is, however, no simple feat. Not only do we need data of exceptional quality, but we also need to perform a sophisticated analysis. We used an algorithm that explores many millions of spectra spanning a wide range of chemical compositions, temperatures, and cloud or haze properties in order to draw our conclusions.”

Titanium oxide is a very rare compound which is known to exist in the atmospheres of cool stars. In small quantities, it acts as a heat absorber, and is therefore likely to be partly responsible for WASP-19b experiencing such high temperatures. In large enough quantities, it can prevent heat from entering or escaping an atmosphere, causing what is known as thermal inversion.

This is a phenomena where temperatures are higher in the upper atmosphere and lower further down. On Earth, ozone plays a similar role, causing an inversion of temperatures in the stratosphere. But on gas giants, this is the opposite of what usually happens. Whereas Jupiter, Saturn, Uranus and Neptune experience colder temperatures in their upper atmospheres, temperatures are much hotter closer to the core due to increases in pressure.

The team believes that the presence of this compound could have a substantial effect on the atmosphere’s temperature, structure and circulation. What’s more, the fact that the team was able to detect this compound (a first for exoplanet researchers) is an indication of how exoplanet studies are achieving new levels of detail. All of this is likely to have a profound impact on future studies of exoplanet atmospheres.

The study would also have not been possible were it not for the FORS2 instrument, which was added to the VLT array in recent years. As Henri Boffin, the instrument scientist who led the refurbishment project, commented:

“This important discovery is the outcome of a refurbishment of the FORS2 instrument that was done exactly for this purpose. Since then, FORS2 has become the best instrument to perform this kind of study from the ground.”

Looking ahead, it is clear that the detection of metal oxides and other similar substances in exoplanet atmospheres will also allow for the creation of better atmospheric models. With these in hand, astronomers will be able to conduct far more detailed and accurate studies on exoplanet atmospheres, which will allow them to gauge with greater certainty whether or not any of them are habitable.

So while this latest planet has no chance of supporting life – you’d have better luck finding ice cubes in the Gobi desert! – its discovery could help point the way towards habitable exoplanets in the future. On step closer to finding a world that could support life, or possibly that elusive Earth 2.0!

Further Reading: ESO, Nature

Posted on by Matt Williams

New Study of Antares Creates the Best Map Ever of a Distant Star

Using ESO’s Very Large Telescope Interferometer astronomers have constructed this remarkable image of the red supergiant star Antares. This is the most detailed image ever of this object, or any other star apart from the Sun.

When stars exhaust their supply of hydrogen fuel, they exit the main sequence phase of their evolution and enter into what is known as the Red Giant Branch (RGB) phase. This is characterized by the stars expanding significantly and becoming tens of thousands of times larger than our Sun. They also become dimmer and cooler, which lends them a reddish-orange appearance (hence the name).

Recently, a team of astronomers used the ESO’s Very Large Telescope Interferometer (VLTI) to map one such star, the red supergiant Antares. In so doing, they were able to create the most detailed map of a star other than our Sun. The images they took also revealed some unexpected things about this supergiant star, all of which could help astronomers to better understand the dynamics and evolution of red giant stars.

The study which details their work, titled “Vigorous Atmospheric Motions in the Red Supergiant Supernova Progenitor Antares“, recently appeared in the journal Nature. As indicated in the study, the team – which was led by Keiichi Ohnaka, an associate professor at the UCN Institute of Astronomy in Chile = relied on the VLTI at the ESO’s Paranal Observatory in Chile to map Antares’s surface and measure the motions of its surface material.

Artist’s impression of the red supergiant star Antares, located 550 ly away in the constellation of Scorpius. Credit: ESO/M. Kornmesser

The purpose of their study was to chart how stars that have entered their RGB phase begin to change. The VLTI is uniquely suited to this task, since it is capable of combining light from four different telescopes – the 8.2-metre Unit Telescopes, or the smaller Auxiliary Telescopes – to create one virtual telescope that has the resolution of a telescope lens measuring 200 meters across.

This allows the VLTI to resolve fine details far beyond what can be seen with a single telescope. As Prof. Ohnaka explained in a recent ESO press statement:

“How stars like Antares lose mass so quickly in the final phase of their evolution has been a problem for over half a century. The VLTI is the only facility that can directly measure the gas motions in the extended atmosphere of Antares — a crucial step towards clarifying this problem. The next challenge is to identify what’s driving the turbulent motions.”

For their study, the team relied on three of the VLTI Auxiliary Telescopes and an instrument called the Astronomical Multi-BEam combineR (AMBER). This near-infrared spectro-interferometric instrument combines three telescopic beams coherently, allowing astronomers to measure the visibilities and closure phases of stars. Using these instruments, the team obtained images of Antares’ surface over a small range of infrared wavelengths.

From these, the team was able to calculate the difference between the speed of atmospheric gas at different locations on Antares’ surface, as well as its average speed over the entire surface. This resulted in a two-dimensional velocity map of Antares, which is the first such map created of another star other than the Sun. As noted, it is also the most-detailed map of any star beyond our Solar System to date.

The study also made some interesting discoveries of what takes place on Antares’ surface and in its atmosphere. For example, they found evidence for high-speed upwellings of gas that reached distances of up to 1.7 Solar radii into space – much farther than previously thought. This, they claimed, could not be explained by convection alone, the process whereby cold material moves downwards and hot material upwards in a circular pattern.

This process occurs on Earth in the atmosphere and with ocean currents, but it is also responsible for moving pockets of hotter and colder gas around within stars. The fact that convection cannot explain the behavior of Antares extended atmosphere would therefore suggests that some new and unidentified process common to red giant stars must be responsible.

These results therefor offer new opportunities for research into stellar evolution, which is made possible thanks to next-generation instruments like the VTLI. As Ohnaka concluded:

“In the future, this observing technique can be applied to different types of stars to study their surfaces and atmospheres in unprecedented detail. This has been limited to just the Sun up to now. Our work brings stellar astrophysics to a new dimension and opens an entirely new window to observe stars.”

Not only is this kind of research improving our understanding of stars beyond our Solar System, it lets us know what to expect when our Sun exits it main sequence phase and begins expanding to become a red giant. Though that day is billions of years away and we can’t be certain humanity will even be around by that time, knowing the mechanics of stellar evolution is important to our understanding of the Universe.
It pays to know that even after we are gone, we can predict what will still be here and for how long. Be sure to check out this 3D animation of Antares, courtesy of the ESO:

Further Reading: ESO, Nature

Posted on by Matt Williams

Stars Orbiting Supermassive Black Hole Show Einstein was Right Again!

Artist's impression of the orbits of three of the stars very close to the supermassive black hole at the center of the Milky Way. Credit: ESO/M. Parsa/L. Calçada

At the center of our galaxy, roughly 26,000 light years from Earth, lies the Supermassive Black Hole (SMBH) known as Sagittarius A*. Measuring 44 million km across, this object is roughly 4 million times as massive as our Sun and exerts a tremendous gravitational pull. Since astronomers cannot detect black holes directly, its existence has been determined largely from the effect it has on the small group of stars orbiting it.

In this respect, scientists have found that observing Sagittarius A* is an effective way of testing the physics of gravity. For instance, in the course of observing these stars, a team of German and Czech astronomers noted subtle effects caused by the black hole’s gravity. In so doing, they were able to yet again confirm some of the predictions made by Einstein’s famous Theory of General Relativity.

Their study, titled “Investigating the Relativistic Motion of the Stars Near the Supermassive Black Hole in the Galactic Center“, was recently published in the Astrophysical Journal. As is indicated in the course of it, the team applied new analysis techniques to existing observations that were made by European Southern Observatory’s (ESO) Very Large Telescope (VLT) and other telescopes over the course of the past 20 years.

Artist’s impression of part of S2s orbit around the supermassive black hole at the center of the Milky Way. Credit: ESO/M. Parsa/L. Calçada

From this, they measured the orbits of the stars that orbit Sagittarius A* to test predictions made by classical Newtonian physics (i.e. Universal Gravitation), as well as predictions based on general relativity. What they found was that one of the stars (S2) showed deviations in its orbit which were defied the former, but were consistent with the latter.

This star, which has 15 times the mass of our Sun, follows an elliptical orbit around the SMBH, completing a single orbit in about 15.6 years. At its closest, it gets to within 17 light hours of the black hole, which is the equivalent of 120 times the distance between the Sun and the Earth (120 AU). Essentially, the research team noted that S2 had the most elliptical orbit of any star orbiting the Supermassive Black Hole.

They also noted a slight change in its orbit – a few percent in the shape and about one-sixth of a degree in orientation. This could only be explained as being due to the relativistic effects caused by Sagittarius A* intense gravity, which cause a precession in its orbit.  What this means is, the elliptical loop of S2’s orbit rotates around the SMBH over time, with its perihelion point aimed in different directions.

Interestingly enough, this is similar to the effect that was observed in Mercury’s orbit – aka. the “perihelion precession of Mercury” – during the late 19th century. This observation challenged classical Newtonian mechanics and led scientists to conclude that Newton’s theory of gravity was incomplete. It is also what prompted Einstein to develop his theory of General Relativity, which offered a satisfactory explanation for the issue.

Should the results of their study be confirmed, this will be the first time that the effects of general relativity have been precisely calculated using the stars that orbit a Supermassive Black Hole. Marzieh Parsa – a PhD student at the University of Cologne, Germany and lead author of the paper – was understandably excited with these results. As she stated in an ESO press statement:

“The Galactic Center really is the best laboratory to study the motion of stars in a relativistic environment. I was amazed how well we could apply the methods we developed with simulated stars to the high-precision data for the innermost high-velocity stars close to the supermassive black hole.“

This study was made possible thanks to the high-accuracy of the VLT’s instruments; in particular, the adaptive optics on the NACO camera and the SINFONI near-infrared spectrometer. These instruments were vital in tracking the star’s close approach and retreat from the black hole, which allowed for the team to precisely determine the shape of its orbit and thusly determine the relativistic effects on the star.

In addition to the more precise information about S2’s orbit, the team’s analysis also provided new and more accurate estimates of Sagittarius A* mass, as well as its distance from Earth. This could open up new avenues of research for this and other Supermassive Black Holes, as well as additional experiments that could help scientists to learn more about the physics of gravity.

The central parts of our Galaxy, the Milky Way, as observed in the near-infrared with the NACO instrument on ESO’s Very Large Telescope. Credit: ESO/MPE/S. Gillessen et al.

The results also provided a preview of the measurements and tests that will be taking place next year. In 2018, the star S2 will be making a very close approach to Sagittarius A*. Scientists from around the world will be using this opportunity to test the GRAVITY instrument, a second-generation instrument that was recently installed on the Very Large Telescope Interferometer (VLTI).

Developed by an international consortium led by the Max Planck Institute for Extraterrestrial Physics, this instrument has been conducting observations of the Galactic Center since 2016. In 2018, it will be used to measure the orbit of S2 with even greater precision, which is expected to be most revealing.  At this time, astrophysicists will be seeking to make additional measurements of the SMBH’s general relativistic effects.

Beyond that, they also hope to detect additional deviations in the star’s orbit that could hint at the existence of new physics! With the right tools trained on the right place, and at the right time, scientists just might find that even Einstein’s theories of gravity were not entirely complete. But in the meantime, it looks like the late and great theoretical physicist was right again!

And be sure to check out this video of the recent study, courtesy of the ESO:

Further Reading: ESO, Astrophysical Journal

Posted on by Matt Williams

Strange Radio Signals Detected from a Nearby Star

Artist's impression of rocky exoplanets orbiting Gliese 832, a red dwarf star just 16 light-years from Earth. Credit: ESO/M. Kornmesser/N. Risinger (skysurvey.org).

Astronomers have been listening to radio waves from space for decades. In addition to being a proven means of studying stars, galaxies, quasars and other celestial objects, radio astronomy is one of the main ways in which scientists have searched for signs of extra-terrestrial intelligence (ETI). And while nothing definitive has been found to date, there have been a number of incidents that have raised hopes of finding an “alien signal”.

In the most recent case, scientists from the Arecido Observatory recently announced the detection of a strange radio signal coming from Ross 128 – a red dwarf star system located just 11 light-years from Earth. As always, this has fueled speculation that the signal could be evidence of an extra-terrestrial civilization, while the scientific community has urged the public not to get their hopes up.

The discovery was part of a campaign being conducted by Abel Méndez – the director of the Planetary Habitability Laboratory (PHL) in Peurto Rico – and Jorge Zuluaga of the Faculty of Exact and Natural Sciences at the University of Antioquia, Colombia. Inspired by the recent discoveries around Proxima Centauri and TRAPPIST-1, the GJ 436 campaign relied on data from Arecibo Observatory to look for signs of exoplanets around nearby red dwarf stars.

Arecibo Observatory, the world’s biggest single dish radio telescope, was and is still being used to image comet 45P/H-M-P. Courtesy of the NAIC – Arecibo Observatory, a facility of the NSF

In the course of looking at data from stars systems like Gliese 436, Ross 128, Wolf 359, HD 95735, BD +202465, V* RY Sex, and K2-18 – which was gathered between April and May of 2017 – they noticed something rather interesting. Basically, the data indicated that an unexplained radio signal was coming from Ross 128. As Dr. Abel Mendez described in a blog post on the PHL website: 

“Two weeks after these observations, we realized that there were some very peculiar signals in the 10-minute dynamic spectrum that we obtained from Ross 128 (GJ 447), observed May 12 at 8:53 PM AST (2017/05/13 00:53:55 UTC). The signals consisted of broadband quasi-periodic non-polarized pulses with very strong dispersion-like features. We believe that the signals are not local radio frequency interferences (RFI) since they are unique to Ross 128 and observations of other stars immediately before and after did not show anything similar.”

After first noticing this signal on Saturday, May 13th at 8:53 p.m., scientists from the Arecibo Observatory and astronomers from the Search for Extra-Terrestrial Intelligence (SETI) Institute teamed up to conduct a follow-up study of the star. This was performed on Sunday, July 16th, using SETI’s Allen Telescope Array and the National Radio Astronomy Observatory‘s (NRAO) Green Bank Telescope.

They also conducted observations of Barnard’s star on that same day to see if they could note similar behavior coming from this star system. This was done in collaboration with the Red Dots project, a European Southern Observatory (ESO) campaign that is also committed to finding exoplanets around red dwarf stars. This program is the successor to the ESO’s Pale Red Dot campaign, which was responsible for discovering Proxima b last summer.

Images of the star systems examined by the GJ 436 Campaign. Credit: PHL/Abel Méndez 

As of Monday night (July 17th), Méndez updated his PHL blog post to announced that with the help of SETI Berkeley with the Green Bank Telescope, that they had successfully observed Ross 128 for the second time. The data from these observatories is currently being collected and processed, and the results are expected to be announced by the end of the week.

In the meantime, scientists have come up with several possible explanations for what might be causing the signal. As Méndez indicated, there are three major possibilities that he and his colleagues are considering:

“[T]hey could be (1) emissions from Ross 128 similar to Type II solar flares, (2) emissions from another object in the field of view of Ross 128, or just (3) burst from a high orbit satellite since low orbit satellites are quick to move out of the field of view. The signals are probably too dim for other radio telescopes in the world and FAST is currently under calibration.”

Unfortunately, each of these possibilities have their own drawbacks. In the case of a Type II solar flare, these are known to occur at much lower frequencies, and the dispersion of this signal appears to be inconsistent with this kind of activity. In the case of it possibly coming from another object, no objects (planets or satellites) have been detected within Ross 128’s field of view to date, thus making this unlikely as well.

The stars currently being examined as part of the GJ 436 campaign. Credit: PHL/Abel Méndez

Hence, the team has something of a mystery on their hands, and hopes that further observations will allow them to place further constrains on what the cause of the signal could be. “[W]e might clarify soon the nature of its radio emissions, but there are no guarantees,” wrote Méndez. “Results from our observations will be presented later that week. I have a Piña Colada ready to celebrate if the signals result to be astronomical in nature.”

And just to be fair, Méndez also addressed the possibility that the signal could be artificial in nature – i.e. evidence of an alien civilization. “In case you are wondering,” he wrote, “the recurrent aliens hypothesis is at the bottom of many other better explanations.” Sorry, alien-hunters. Like the rest of us, you’ll just have to wait and see what can be made of this signal.

Further Reading: AFP, PHL

Posted on by Evan Gough

Construction Begins on the Next Super Telescope

This artist’s rendering shows the Extremely Large Telescope in operation on Cerro Armazones in northern Chile. The telescope is shown using lasers to create artificial stars high in the atmosphere. Image: ESO/E-ELT
This artist’s rendering shows the Extremely Large Telescope in operation on Cerro Armazones in northern Chile. The telescope is shown using lasers to create artificial stars high in the atmosphere. Image: ESO/E-ELT

The construction of the world’s largest telescope has begun. At a ceremony at the European Southern Observatory’s (ESO) Paranal Observatory in Chile, officials gathered to celebrate the first stone of the European Extremely Large Telescope’s (E-ELT) long-awaited construction. Sophisticated telescope projects like the E-ELT take many years, so we can expect another similar ceremony sometime in 2021, when the E-ELT will see first light.

The E-ELT is the ESO’s flagship observatory. It’s primary mirror will be a 39.3 meter (129 ft.) monstrosity that will observe in the visible, near-infrared, and mid-infrared spectra. The construction of the site began in 2014, but this ceremony marks the beginning of the construction of the main telescope and its dome. The ceremony also marks the connection of the telescope to the electricity grid.

The Chilean President, Michelle Bachelet Jeria, attended the ceremony. She was welcomed by the Director General of ESO Tim de Zeeuw, by ELT Programme Manager Roberto Tamai, and by other officials from the ESO. Staff from the La Silla Paranal Observatory, and numerous engineers and technicians—as well as numerous representatives from Chilean government and industry—also attended the ceremony.

“With the symbolic start of this construction work, we are building more than a telescope here.” – President of the Republic of Chile, Michelle Bachelet Jeria

In her speech, the President spoke in favor of the E-ELT, and in support of science and cooperation. “With the symbolic start of this construction work, we are building more than a telescope here: it is one of the greatest expressions of scientific and technological capabilities and of the extraordinary potential of international cooperation.”

At the ceremony, a time capsule from ESO was sealed into place. The capsule is a hexagon shaped, one-fifth scale model of the E-ELT containing a poster made of photographs of current ESO staff, and a copy of the book detailing the E-ELT’s science goals.

The first stone ceremony is definitely an important milestone for this Super Telescope, but it’s just one of the milestones reached by the E-ELT in the past two weeks.

The secondary mirror for the E-ELT has already been cast. At 4.2 meters in diameter, it is the largest secondary mirror ever used on an an optical telescope. Image: ESO/Schott.
The secondary mirror for the E-ELT has already been cast. At 4.2 meters in diameter, it is the largest secondary mirror ever used on an an optical telescope. Image: ESO/Schott.

The secondary mirror for the E-ELT has already been cast, and the ESO has announced that the contracts for the primary mirror have now been signed. The primary mirror segment blanks, all 798 of them, will be made by the Germany company SCHOTT. Once produced, they will be polished by the French company Safran Reosc. Safran Reosc will also mount and test the mirror segments.

“This has been an extraordinary two weeks!” – Tim de Zeeuw, European Southern Observatory’s Director General

Tim de Zeeuw, ESO’s Director General, is clearly excited about the progress being made on the E-ELT. At the contract signing, de Zeeuw said, “This has been an extraordinary two weeks! We saw the casting of the ELT’s secondary mirror and then, last Friday, we were privileged to have the President of Chile, Michelle Bachelet, attend the first stone ceremony of the ELT. And now two world-leading European companies are starting work on the telescope’s enormous main mirror, perhaps the biggest challenge of all.”

This artist's rendering shows the huge segmented primary mirror of the ESO Extremely Large Telescope (ELT). Contracts for the manufacture of the mirror segments were signed on 30 May 2017. Image: ESO/L. Calcada
This artist’s rendering shows the huge segmented primary mirror of the ESO Extremely Large Telescope (ELT). Contracts for the manufacture of the mirror segments were signed on 30 May 2017. Image: ESO/L. Calcada

It’s taken an enormous amount of work to get to the construction stage of the world’s largest telescope. Scientist’s, engineers, and technicians have been working for years to get this far. But without the contribution of Chile, none of it would happen. Chile is the world’s astronomy capital, and they continue working with the ESO and other nations to drive scientific discovery forward.

The E-ELT has three broad-based science objectives. It will:

  • Probe Earth-like exoplanets for signs of life
  • Study the nature of dark energy and dark matter
  • Observe the Universe’s early stages to understand our origins and the origin of galaxies and solar systems

Along the way, it will no doubt raise new questions that we can’t even imagine yet.

Further Reading:

Posted on by Evan Gough

Enjoy The Biggest Infrared Image Ever Taken Of The Small Magellanic Cloud Without All That Pesky Dust In The Way

The Small Magellanic Cloud is one of the highlights of the southern sky. It can be seen with the naked eye. But it is obscured by clouds of interstellar gas and dust, which makes it hard for optical telescopes to get a good look at it. This image, taken with the ESO's VISTA. is the biggest-ever image of the SMC, and shows millions of stars. Credit: ESO/VISTA VMC
The Small Magellanic Cloud is one of the highlights of the southern sky. It can be seen with the naked eye. But it is obscured by clouds of interstellar gas and dust, which makes it hard for optical telescopes to get a good look at it. This image, taken with the ESO's VISTA. is the biggest-ever image of the SMC, and shows millions of stars. Credit: ESO/VISTA VMC

The Small Magellanic Cloud (SMC) galaxy. Credit: ESA/VISTA
The Small Magellanic Cloud (SMC) galaxy. Credit: ESA/VISTA

The Small Magellanic Cloud (SMC) is one of the Milky Way’s nearest companions (along with the Large Magellanic Cloud.) It’s visible with the naked eye in the southern hemisphere. A new image from the European Southern Observatory’s (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) has peered through the clouds that obscure it and given us our biggest image ever of the dwarf galaxy.

The SMC contains several hundred million stars, is about 7,000 light years in diameter, and is about 200,000 light years away. It’s one of the most distant objects that we can see with the naked eye, and can only be seen from the southern hemisphere (and the lowest latitudes of the northern hemisphere.)

The Small Magellanic Cloud is located in the Tucana constellation (The Toucan) in the southern hemisphere. The SMC is shown in green outline around the word 'Tucana'. Also shown are NGC 104 and NGC 362, unrelated objects that are much closer to Earth. Image: ESO, IAU and Sky & Telescope
The Small Magellanic Cloud is located in the Tucana constellation (The Toucan) in the southern hemisphere. The SMC is shown in green outline around the word ‘Tucana’. Also shown are NGC 104 and NGC 362, unrelated objects that are much closer to Earth. Image: ESO, IAU and Sky & Telescope

The SMC is a great target for studying how stars form because it’s so close to Earth, relatively speaking. But the problem is, its detail is obscured by clouds of interstellar gas and dust. So an optical survey of the Cloud is difficult.

But the ESO’s VISTA instrument is ideal for the task. VISTA is a near-infrared telescope, and infrared light is not blocked by the dust. VISTA was built at the ESO’s Paranal Observatory, in the Atacama Desert in Chile where it enjoys fantastic observing conditions. VISTA was designed to perform several surveys, including the Vista Magellanic Survey.

Explore the Zoomable image of the Small Magellanic Cloud. (You won’t be disappointed.)

The VISTA Magellanic Survey is focused on 3 main objectives:

  • The study of stellar populations in the Magellanic Clouds
  • The history of star formation in the Magellanic Clouds
  • The three-dimensional structure of the Magellanic Clouds

An international team led by Stefano Rubele of the University of Padova has studied this image, and their work has produced some surprising results. VISTA has shown us that most of the stars in this image are much younger than stars in other neighbouring galaxies. It’s also shown us that the SMC’s morphology is that of a warped disc. These are only early results, and there’s much more work to be done analyzing the VISTA image.

VISTA inside its enclosure at Paranal. VISTA has a 4.1 meter mirror, and its job is to survey large sections of the sky at once. In the background is the ESO's Very Large Telescope. Image: G. Hüdepohl
VISTA inside its enclosure at Paranal. VISTA has a 4.1 meter mirror, and its job is to survey large sections of the sky at once. In the background is the ESO’s Very Large Telescope. Image: G. Hüdepohl (atacamaphoto.com)/ESO

The team presented their research in a paper titled “The VMC survey – XIV. First results on the look-back time star formation rate tomography of the Small Magellanic Cloud“, published in the journal Monthly Notices of the Royal Astronomical Society.

As the authors say in their paper, the SMC is a great target for study because of its “rich population of star clusters, associations, stellar pulsators, primary distance indicators, and stars in shortlived evolutionary stages.” In a way, we’re fortunate to have the SMC so close. But studying the SMC was difficult, until the VISTA came online with its infrared capabilities.

VISTA saw first light on December 11th, 2009. It’s time is devoted to systematic surveys of the sky. In its first five years, it has undertaken large surveys of the entire southern sky, and also studied small patches of the sky to discern extremely faint objects. The leading image in this article is from the Vista Magellanic Survey, a survey covering 184 square degrees of the sky, taking in both the Small Magellanic Cloud and the Large Magellanic Cloud, and their environment.

Source: VISTA Peeks Through the Small Magellanic Cloud’s Dusty Veil

Posted on by Evan Gough

Rise of the Super Telescopes: The European Extremely Large Telescope

This artist’s rendering of the E-ELT is based on the detailed construction design for the telescope. Image: ESO/L. Calçada/ACe Consortium

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at 6 of the world’s Super Telescopes:

The European Extremely Large Telescope

The European Extremely Large Telescope (E-ELT) is an enormous ‘scope being built by the European Southern Observatory. It’s under construction right now in the high-altitude Atacama Desert of northern Chile. The ESO, with its partners, has built some of the largest and most technically advanced telescopes in the world, like the Atacama Large Millimeter Array (ALMA) and the Very Large Telescope (VLT.) But with a 39 meter primary mirror, the E-ELT will dwarf the other telescopes in the ESO’s fleet.

As Dr Michele Cirasuolo, Programme Scientist for the ELT told Universe Today, “The Extremely Large Telescope (ELT) is the flagship project of the European Southern Observatory (ESO), and when completed in 2024 will be the largest optical/infrared telescope in the world. It represents the next step forward and it will complement the research done with the GMT (Giant Magellan Telescope) and other large telescopes being built.”

This artist’s rendering of the E-ELT shows the 39 meter segmented mirror at the heart of the scope. ESO/L. Calçada/ACe Consortium

The E-ELT is the successor to the Overwhelmingly Large Telescope (OWL), which was the ESO backed away from due to its €1.5 billion price tag. Instead, the ESO focussed on the E-ELT. The site for the E-ELT was selected in 2010, and over the next couple years the design was finalized.

Like other telescopes—including the Keck Telescope—the E-ELT’s primary mirror will be made up of individually manufactured hexagonal segments; 798 of them. The primary mirror will be fitted with edge sensors to ensure that each segment of the mirror is corrected in relation to its neighbours as the scope is aimed or moved, or as it is disturbed by temperature changes, wind, or vibrations.

The E-ELT is actually a 5 mirror system. Along with the enormous primary mirror, and the secondary mirror, there are three other mirrors. An unusual aspect of the E-ELT’s design is its tertiary mirror. This tertiary mirror will give the E-ELT better image quality over a larger field of view than a primary and secondary mirror can.

The ‘scope also has two other mirrors which provide adaptive optics and image stabilization, as well as allowing more large science instruments to be mounted to the ‘scope simultaneously.

This diagram shows the novel 5-mirror optical system of ESO’s Extremely Large Telescope (ELT). Before reaching the science instruments the light is first reflected from the telescope’s giant concave 39-metre segmented primary mirror (M1), it then bounces off two further 4-metre-class mirrors, one convex (M2) and one concave (M3). The final two mirrors (M4 and M5) form a built-in adaptive optics system to allow extremely sharp images to be formed at the final focal plane. Image By ESO – https://www.eso.org/public/images/eso1704a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=55268266

The Science: What Will the E-ELT Study?

The E-ELT is designed for an ambitious science agenda. One of the most exciting aspects of the E-ELT is its potential to capture images of extra-solar planets. The 39 meter mirror will not only collect more light from distant, faint objects, but will provide an increase in angular resolution. This means that the telescope will be capable of distinguishing objects that are close together.

As Dr. Cirasuolo explains, “This will allow the ELT to image exoplanets nearer to the star they are orbiting. We aim to probe planets in the so called habitable zone (where liquid water could exist on their surfaces) and take spectra to analyse the composition of their atmospheres.”

The E-ELT has other goals as well. It aims to probe the formation and evolution of planetary systems, and to detect water and organic molecules in protoplanetary disks around stars as they form. It will look at some of the most distant objects possible—the first stars, galaxies, and black holes—to try to understand the relationships between them.

The telescope is also designed to study the first galaxies, and to chart their evolution over time. As if this list of science goals isn’t impressive enough, the E-ELT holds out the hope of directly measuring the acceleration in the expansion of the Universe.

This video explains the design of the E-ELT and some of its science goals.

These are all fascinating goals, but for many of us the most compelling question we face is “Are We Alone?” Dr. Cirasuolo feels the same. As he told Universe Today, “The ultimate goal is finding signs of life. Certainly the next generation of telescopes will provide a huge leap forward in our understanding of extra solar planets and for the search for life in the Universe.”

The E-ELT won’t be working alone. Other Super Telescopes, like the Giant Magellan Telescope, the Thirty Meter Telescope, and even the Large Synoptic Survey Telescope, will all be working in conjunction to expand the frontier of knowledge.

It may be a very long time, if ever, before we find life somewhere else in the Universe. But by expanding our knowledge of exo-planets, the E-ELT is going to be a huge part of the ongoing effort. A few years ago, we weren’t even certain that we would find many planets around other stars. Now the discovery of exoplanets is almost commonplace. If the E-ELT lives up to its promise, then capturing actual images of exoplanets may become commonplace as well.

Posted on by Matt Williams

Huge News, Seven Earth-Sized Worlds Orbiting a Red Dwarf, Three in the Habitable Zone

Illustration showing the possible surface of TRAPPIST-1f, one of the newly discovered planets in the TRAPPIST-1 system. Credits: NASA/JPL-Caltech
Illustration showing the possible surface of TRAPPIST-1f, one of the newly discovered planets in the TRAPPIST-1 system. It's a very active flare star. Credits: NASA/JPL-Caltech

In what is surely the biggest news since the hunt for exoplanets began, NASA announced today the discovery of a system of seven exoplanets orbiting the nearby star of TRAPPIST-1. Discovered by a team of astronomers using data from the TRAPPIST telescope in Chile and the Spitzer Space Telescope, this find is especially exciting since all of these planets are believed to be Earth-sized and terrestrial (i.e. rocky).

But most exciting of all is the fact that three of these rocky exoplanets orbit within the star’s habitable zone (aka. “Goldilocks Zone”). This means, in effect, that these planets are capable of having liquid water on their surfaces and could therefore support life. As far as extra-solar planet discoveries go, this is without precedent, and the discovery heralds a new age in the search for life beyond our Solar System.

Continue reading “Huge News, Seven Earth-Sized Worlds Orbiting a Red Dwarf, Three in the Habitable Zone”

Posted on by Matt Williams

A “Breakthrough” to Search for Planets in Closest Star System to Earth

Artist’s impression of Proxima b, which was discovered using the Radial Velocity method. Credit: ESO/M. Kornmesser

Ever since the European Southern Observatory (ESO) announced that they had discovered an exoplanet in the nearby system of Proxima Centauri, there have been a lot of questions about this exoplanet. In addition to whether or not this planet could actually support life, astronomers have also been eager to see if its companion stars – Alpha Centauri A and B – have exoplanets too.

Prior to the discovery of Proxima b, Alpha Centauri was thought to host the closest exoplanets to Earth (Alpha Bb and Bc). However, time has cast doubt on the existence of the first, while the second’s existence remains unconfirmed. But thanks to a recent agreement between the ESO and Breakthrough Initiatives, we may yet find out if there are exoplanets in Alpha Centauri – which will come in handy when it comes time to explore there!

In accordance with this agreement, Breakthrough Initiatives will provide additional funds so that the ESO’s Very Large Telescope (VLT), located at the La Silla Paranal Observatory in Chile, can be modified to conduct a special search program of Alpha Centauri. This will involve upgrading the VLT Imager and Spectrometer for mid-Infrared (VISIR) instrument with new equipment that will enhance its planet-hunting abilities.

Image of the Alpha Centauri AB system and its distant and faint companion, Proxima Centauri. Credit: ESO

This includes a new instrument module that will allow the VLT to use a technique known as coronagraphy – a form of adaptive optics that corrects for a star’s brightness, thus making it easier for a telescope to spot the thermal glow of orbiting planets around them. While the Breakthrough Prize Foundation will pay a large fraction of the upgrade costs, the ESO will be making the VLT and its staff available to conduct the survey – which is scheduled for 2019.

Such an agreement is truly a win-win scenario. For the ESO, this will not only improve the VLT’s imaging abilities, but will also assist with the development of the European Extremely Large Telescope (E-ELT). This proposed array, which is scheduled for completion by 2024, will rely on the Mid-infrared E-ELT Imager and Spectrograph (METIS) instrument to hunt for potentially habitable exoplanets.

Any lessons learned from the upgrade of VISIR will allow them to develop the necessary expertise to run METIS, and will also allow them to test the effectiveness of the technology beforehand. For Breakthrough Initiatives, determining if there are any planets in the Alpha Centauri system will go a long way towards helping them mount their historic mission to this star.

In the coming years, Breakthrough Initiatives hopes to mount the first interstellar voyage in history using a lightsail and nanocraft that would rely on lasers to push it up to relativistic speeds (20% the speed of light). Known as Breakthrough Starshot, this craft could be ready to launch in a few years time, and would reach Alpha Centauri in just 20 years time.

The ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile and a stellar backdrop showing the location of Alpha Centauri. Credit: ESO

Once there, the nanocraft (using a series of microsensors) would relay information back to Earth about the Alpha Centauri system – which would include any information on its system of planets, and whether or not they are habitable. Hence, determining if there’s anything there to study in the first place will help lay the groundwork for the mission.

As Professor Avi Loeb – the Frank B. Baird, Jr. Professor of Science at Harvard and a member of the Breakthrough Starshot Advisory Committee – told Universe Today via email:

“We hope that the partnership between the Breakthrough Prize Foundation and ESO will lead to the discovery of new habitable planets around the nearest stars. Once discovered, we could search for the molecular signatures of life in the atmosphere of these planets, and potentially even send a spacecraft that will reach them within our lifetime. The latter is the driver for the Starshot Initiative. The discovery of habitable nearby planets will provide us with targets for photography by gram-scale spacecrafts, launched at a fraction of the speed of light and  equipped with cameras. For example, we would like to find out whether such planets are covered by blue oceans, green vegetation or yellow deserts.”

It’s one of the hallmarks of the new space age: a private and public organization coming together for the sake of mutual benefit. But when those benefits include advancing scientific research, space exploration, and the hunt for habitable planets other than our own, it truly is a win-win situation!

In the meantime, enjoy this video provided by ESO about their new partnership with Breakthrough Initiatives:

Further Reading: ESO, Breakthrough Initiatives