Observations of a blown mind

Posts tagged “Astronomy

Science and early Christianity


Over the last thousand years Christianity has adopted many things from other religions, but it also took from science too.

A Spherical Harmony

The earliest ancient civilizations all shared the same fundamental view of the universe; that our earth lay at the centre. The characteristically inventive Sumerians of what we now call Iraq; the Amorite dynasty that founded the Babylonians; and also the North East African civilisation of the ancient Egyptians; all these ancient civilizations had the Sun, Moon, stars, and planets revolving around us. The specific explanations varied from society to society, but the viewpoint that came to dominate the minds of Europeans was established by successive generations of the ancient Greek philosophers. Though I say “ancient greeks”  they were in reality learned philosophers who lived across many centuries with their theories of the cosmos being somewhat refined over a time period scanning more than six hundred years.

Te first known idea of the stars being fixed to a sphere, or hemisphere, rotating around the earth is attributed to Anaximenes of Miletus, who lived in the 6th century BC. Like his predecessors, Anaximenes was preoccupied with cosmology, searching for the world’s origin in which he is most known for his assertion that air is the most basic and originary material and the source of all things. While empirical evidence was essential in Anaximenes’ work, the less evidentiary notions of the divine remained apparent as well. Perhaps in line with early Greek literature that rendered air as the soul, as in the ‘breath of life,’ Anaximenes relates air with god and the divine, according to the accounts of Aetius. The qualities of air, that has similar attributes as the qualities of Anaximander’s aperion, are those of the divine and the eternal. It is posited, by Aetius and later by Cicero, that there is a strong correlation between the notion of air as an originary principle element and the notion of air and breath as the divine and eternal substance of the soul and of god.

In the 6th century, Anaximenes of Miletus, saw the Earth as a kind of flat disc, or a flat-topped cylinder that floated like a cork in the air. Pythagoras of Samos – the same Pythagoras whose theory we use today to calculate the area of a triangle – changed the disc to a globe then placing it at the centre of concentric spheres, one for the Sun, the Moon and each of the planets, with the other stars ‘fixed’ at the furthest distance. For Pythagoras, the physical distances separating the spheres was of great importance, even seeing the seven planetary spheres (Moon and Sun included) and the shpere of the stars being separated in the same seven ratios as those of the musical scale. It was this particular notion that gave us the concept of the “harmony of the spheres” that was to resonate for two milennia.

The model that later became fixed stemmed from a proposition laid down by the philospher and methematician Plato circa.  400 BC. For Plato, the circle was the perfect form and he was totally convinced that the Sun and the Moon revolved around a spherical Earth in circular orbits. Plato’s students were left with the challenge of  creating a model that explained his philosophy. Eudoxus of Cnidus offered an ingenious solution of multiple concentric spheres. The orbit of our Moon illustrates this idea; to explain its apparent movement through the heavens the Moon needed three spheres; one rotating every day in order to explain the rising and setting; a second rotating every month in order to explain the movement through the zodiac (movement against the stars); and a third rotating monthly on a slightly different axis in order to explain its variation in latitude. To see Eudoxus solution click here.

The problem that was obvious to the ancient astronomers was that planets behaved in a strange fashion, sometimes they were closer, sometimes farther away from Earth, sometimes speeding up and sometimes slowing down or even appearing to travel backwards. The word “planet” comes from the Ancient Greek word for “wonder”. Our friend Eudoxus required 27 concentric spheres to explain the movements in the heavens, but that was later refined by his contemporary, the great philosopher Aristotle, in to a model of greater perfection. In an attempt to make sense of what was observed, he placed 55 concentric spheres around the Earth, each responsible for a specific movement of the heavenly bodies, always though in the perfect eternal motion of a circle, as they passed through the substance out there that he called the “aether”. At the furthest extremities he placed the “Unmoved Mover”, or the force that centuries later came to represent the all-powerful Christian God.

All this could have, and should have, been rendered irrelevant had the ideas of Aristarchus, also of Samos, caught on some 200 years later! Essentially he had it all worked out. He placed the Sun at the centre of the cosmos, with the Earth and other planets circling it, in the same order as we know them today.

Image credit Wikipedia Commons

Image credit Wikipedia Commons

But his theories did not stand up to the withering logic of the time. He was unpicking the established teachings of the great Aristotle and Plato. Yet it didn’t gain kudos because it seemed so self-evidently wrong. If indeed the Earth were moving through space, why would an object thrown upwards come straight back down? Surely it would land at a distance away as the ground the individual were standing on moved through space. So, the common sense of the time indicated that Aristotle had it right.

 

 

 

 


Astronomers discover a planet that, well, shouldn’t be there


The discovery of a giant planet orbiting its star at 650 times the average Earth-Sun distance has astronomers puzzled over how such a strange system came to be

An international team of astronomers, led by a University of Arizona graduate student, has discovered the most distantly orbiting planet found to date around a single, sun-like star. It is the first exoplanet – a planet outside of our solar system – discovered at the UA.

an artist's conception of a young planet in a distant orbit around its host star. The star still harbors a debris disk, remnant material from star and planet formation, interior to the planet's orbit (similar to the HD106906 system). Credit: NASA/JPL-Caltech

an artist’s conception of a young planet in a distant orbit around its host star. The star still harbors a debris disk, remnant material from star and planet formation, interior to the planet’s orbit (similar to the HD106906 system).
Credit: NASA/JPL-Caltech

Weighing in at 11 times Jupiter’s mass and orbiting its star at 650 times the average Earth-Sun distance, planet HD 106906 b is unlike anything in our own Solar System and throws a wrench in planet formation theories.

“This system is especially fascinating because no model of either planet or star formation fully explains what we see,” said Vanessa Bailey, who led the research. Bailey is a fifth-year graduate student in the UA’s Department of Astronomy.

It is thought that planets close to their stars, like Earth, coalesce from small asteroid-like bodies born in the primordial disk of dust and gas that surrounds a forming star. However, this process acts too slowly to grow giant planets far from their star. Another proposed mechanism is that giant planets can form from a fast, direct collapse of disk material. However, primordial disks rarely contain enough mass in their outer reaches to allow a planet like HD 106906 b to form. Several alternative hypotheses have been put forward, including formation like a mini binary star system.

“A binary star system can be formed when two adjacent clumps of gas collapse more or less independently to form stars, and these stars are close enough to each other to exert a mutual gravitation attraction and bind them together in an orbit,” Bailey explained. “It is possible that in the case of the HD 106906 system the star and planet collapsed independently from clumps of gas, but for some reason the planet’s progenitor clump was starved for material and never grew large enough to ignite and become a star.”

According to Bailey, one problem with this scenario is that the mass ratio of the two stars in a binary system is typically no more than 10-to-1.

“In our case, the mass ratio is more than 100-to-1,” she explained. “This extreme mass ratio is not predicted from binary star formation theories – just like planet formation theory predicts that we cannot form planets so far from the host star.”

This system is also of particular interest because researchers can still detect the remnant “debris disk” of material left over from planet and star formation.

“Systems like this one, where we have additional information about the environment in which the planet resides, have the potential to help us disentangle the various formation models,” Bailey added. “Future observations of the planet’s orbital motion and the primary star’s debris disk may help answer that question.”

At only 13 million years old, this young planet still glows from the residual heat of its formation. Because at 2,700 Fahrenheit (about 1,500 degrees Celsius) the planet is much cooler than its host star, it emits most of its energy as infrared rather than visible light. Earth, by comparison, formed 4.5 billion years ago and is thus about 350 times older than HD 106906 b.

 

This is a discovery image of HD 106906 b in the thermal infrared (4µm wavelength) from MagAO/Clio2, processed to remove the bright light from its host star, HD 106906 A. The planet is than 20 times farther away from HD 106906 A than Neptune is from our Sun. AU stands for Astronomical Unit, the average distance of the Earth and the Sun. Credit: Vanessa Bailey

This is a discovery image of HD 106906 b in the thermal infrared (4µm wavelength) from MagAO/Clio2, processed to remove the bright light from its host star, HD 106906 A. The planet is than 20 times farther away from HD 106906 A than Neptune is from our Sun. AU stands for Astronomical Unit, the average distance of the Earth and the Sun.
Credit: Vanessa Bailey

Direct imaging observations require exquisitely sharp images, akin to those delivered by the Hubble Space Telescope. To reach this resolution from the ground requires a technology called Adaptive Optics, or AO. The team used the new Magellan Adaptive Optics (MagAO) system and Clio2 thermal infrared camera – both technologies developed at the UA – mounted on the 6.5 meter-diameter Magellan telescope in the Atacama Desert in Chile to take the discovery image.

UA astronomy professor and MagAO principal investigator Laird Close said: “MagAO was able to utilize its special Adaptive Secondary Mirror, with 585 actuators, each moving 1,000 times a second, to remove the blurring of the atmosphere. The atmospheric correction enabled the detection of the weak heat emitted from this exotic exoplanet without confusion from the hotter parent star.”

“Clio was optimized for thermal infrared wavelengths, where giant planets are brightest compared to their host stars, meaning planets are most easily imaged at these wavelengths,” explained UA astronomy professor and Clio principal investigator Philip Hinz, who directs the UA Center for Astronomical Adaptive Optics.

The team was able to confirm that the planet is moving together with its host star by examining Hubble Space Telescope data taken eight years prior for another research program. Using the FIRE spectrograph, also installed at the Magellan telescope, the team confirmed the planetary nature of the companion. “Images tell us an object is there and some information about its properties but only a spectrum gives us detailed information about its nature and composition,” explained co-investigator Megan Reiter, a graduate student in the UA Department of Astronomy. “Such detailed information is rarely available for directly imaged exoplanets, making HD 106906 b a valuable target for future study.”

“Every new directly detected planet pushes our understanding of how and where planets can form,” said co-investigator Tiffany Meshkat, a graduate student at Leiden Observatory in the Netherlands. “This planet discovery is particularly exciting because it is in orbit so far from its parent star. This leads to many intriguing questions about its formation history and composition. Discoveries like HD 106906 b provide us with a deeper understanding of the diversity of other planetary systems.”

Notes:

The research paper, “HD 106906 b: A Planetary-mass Companion Outside a Massive Debris Disk,” has been accepted for publication in The Astrophysical Journal Letters and will appear in a future issue. An online version is available for download at http://arxiv.org/abs/1312.1265 .

The members of the discovery team are Vanessa Bailey (UA), Tiffany Meshkat (Leiden Observatory [LO]), Megan Reiter (UA), Katie Morzinski (UA), Jared Males (UA), Kate Y. L. Su (UA), Philip M. Hinz (UA), Matthew Kenworthy (LO), Daniel Stark (UA), Eric Mamajek (University of Rochester), Runa Briguglio (Arcetri Observatory [AO]), Laird M. Close (UA), Katherine B. Follette (UA), Alfio Puglisi (AO), Timothy Rodigas (UA, Carnegie Institute of Washington [CIW]), Alycia J. Weinberger (CIW), and Marco Xompero (AO).


Exploring the extreme Universe with a new resource


Scientists led by the University of Leicester have set a new record for cosmic X-ray sources ever sighted – creating an unprecedented cosmic X-ray catalogue that will provide a valuable resource allowing astronomers to explore the extreme Universe.

This is a sky distribution of the density of objects in the 3XMM catalog, shown in Galactic coordinates. The inset shows a zoom of the small region indicated where the individual sources can be seen. Credit: ESA/XMM-Newton/EPIC/M. Watson (University of Leicester)

This is a sky distribution of the density of objects in the 3XMM catalog, shown in Galactic coordinates. The inset shows a zoom of the small region indicated where the individual sources can be seen.
Credit: ESA/XMM-Newton/EPIC/M. Watson (University of Leicester)

 

The XMM-Newton Survey Science Centre, led by a team from the University of Leicester’s Department of Physics and Astronomy, used the University’s ‘ALICE’ supercomputer to help them produce a new X-ray catalogue, dubbed “3XMM”.

This new catalogue contains over half a million X-ray source detections, representing a 50% increase over previous catalogues and is the largest catalogue of X-ray sources ever produced. This vast inventory is also home to some of the rarest and most extreme phenomena in the Universe, such as tidal disruption events – when a black hole swallows another star, producing prodigious outbursts of X-ray emission.

Professor Mike Watson of the University of Leicester, who leads the XMM-Newton Survey Science Centre, said: “The catalogue contains more than half a million sources, all of which are provided to a better quality than ever before.

“Using the University’s £2.2m High Performance Computer meant we could process the data up to a hundred times faster than before. This was key for testing and implementing advanced new processing strategies.”

“The catalogue provides enormous scope for new discoveries as well as in-depth studies of large samples. XMM-Newton is pre-eminent amongst current X-ray missions in its ability to perform `survey’ science, with a chance to find previously undetected objects and then explore their properties.”

The catalogue provides an exceptional dataset for generating large, well-defined samples of objects such as active galactic nuclei, clusters of galaxies, interacting compact binaries, and active stellar coronae.

The XMM-Newton Survey Science Centre is one of the teams behind the European Space Agency’s (ESA) X-ray Multi-Mirror Mission (XMM-Newton). Since Earth’s atmosphere blocks out all X-rays, only a telescope in space can detect and study celestial X-ray sources. The XMM-Newton mission is helping scientists to solve a number of cosmic mysteries, ranging from the enigmatic black holes to the origins of the Universe itself.

The sources in the 3XMM catalogue are identified and isolated from serendipitous data recorded by XMM-Newton’s EPIC X-ray cameras, built by a team also led by the University. In each of the 600-700 observations made each year, around 70 extra sources are captured in addition to the target object which usually only takes up a small fraction of the field of view. Covering observations between February 2000 and December 2012, the catalogue contains some 531 261 X-ray source detections relating to 372 728 unique X-ray sources.

Professor Watson, who is Head of X-ray and Observational Astronomy in the Department of Physics and Astronomy, adds: “The third XMM-Newton Serendipitous Source Catalogue shows how much added value can be gained from the observations. I’d like to pay tribute to the efforts of the whole team which were crucial to completing this major undertaking.

“3XMM is the largest catalogue of X-ray sources ever produced. As such it offers an unparalleled resource for exploring cosmic X-ray populations, in particular in studying Active Galactic Nuclei (AGN) – those galaxies such as quasars which harbour a super-massive black hole at their centres. Such active galaxies dominate the detections in the 3XMM catalogue, meaning that 3XMM is the key to unlocking a storehouse of several hundred thousand AGN.”

Notes:

  • Three years’ research led by University of Leicester Department of Physics and Astronomy
  • Team produces new catalogue with 531,261 detections of X-ray emitting objects – a new record
  • 372,728 unique X-ray sources identified
  • The total area covered on the sky by the combined observation fields is ~1400 square degrees

Jupiter’s atmosphere still contains water supplied by the Shoemaker-Levy 9 impact


In July 1994, the comet Shoemaker-Levy 9 (SL9) hit Jupiter and left visible scars on the Jovian disk for weeks. This spectacular event was the first direct observation of an extraterrestrial collision in the solar system, and it was followed worldwide by professional and amateur astronomers.

Caption: This shows an abundance of water in Jupiter's stratosphere. The north-south asymmetry is clearly observed. The green and red areas correspond to the highest abundances. Credit: Astronomy & Astrophysics, Cavalié et al. 2013, A&A, 553, A21

Caption: This shows an abundance of water in Jupiter’s stratosphere. The north-south asymmetry is clearly observed. The green and red areas correspond to the highest abundances.
Credit: Astronomy & Astrophysics, Cavalié et al. 2013, A&A, 553, A21

 

SL9 was discovered orbiting Jupiter by astronomers David Levy and Carolyn and Eugene M. Shoemaker on March 24, 1993. It was the first comet observed orbiting a planet rather than the Sun. SL9 was found to be composed of 21 fragments. Soon after that, orbital studies showed that the comet had passed within Jupiter’s Roche limit in July 1992. Inside this limit, the planet’s tidal forces are strong enough to disintegrate a body held together by its own gravity, thus explaining SL9’s fragmentation. Even more interestingly, the studies showed that SL9’s orbit would pass within Jupiter in July 1994 and that the comet would then collide with the planet, with impacts in the southern hemisphere near 44°S latitude.

The SL9 impact and its subsequent scars on Jupiter were observed for weeks, but its chemical impact on Jupiter’s atmosphere lasted even longer. Emission from water vapor was observed during the fireball phase of the SL9 impacts, but from that observation, it was difficult to assess how this would modify Jupiter’s composition on the long term. In 1997, the ESA Infrared Space Observatory (ISO) detected water vapor in the stratosphere of Jupiter. At that time, astronomers suspected that it might be a consequence of the SL9 impact because comets are known to be water-rich bodies. However, there were other possible sources of water: interplanetary dust particles produced by cometary activity and asteroid collisions, icy rings, or one of the 60 Jovian satellites.

Nearly twenty years after this major impact, astronomers are still observing its consequences on Jupiter. T. Cavalié and his colleagues [1] observed Jupiter with the ESA Herschel Space Observatory, which is sensitive enough to map the abundance of water vs. latitude and altitude in the Jovian stratosphere. These observations, which have now been published inAstronomy & Astrophysics, show a clear north-south asymmetry in the distribution of water, with more water in the south. They indicate that 95% of the water currently observed on Jupiter comes from the comet.

Notes –

[1] The team includes T. Cavalié, H. Feuchtgruber, E. Lellouch, M. de Val-Borro, C. Jarchow, R. Moreno, P. Hartogh, G. Orton, T. Greathouse, F. Billebaud, M. Dobrijevic, L. Lara, A. Gonzalez, and H. Sagawa.

Spatial distribution of water in the stratosphere of Jupiter from Herschel HIFI and PACS observations, by T. Cavalié, H. Feuchtgruber, E. Lellouch, M. de Val-Borro, C. Jarchow, R. Moreno, P. Hartogh, G. Orton, T. Greathouse, F. Billebaud, M. Dobrijevic, L. Lara, A. Gonzalez, and H. Sagawa.

Published in Astronomy & Astrophysics, 2013, vol. 553, A21


Paddington?


[Click Image to enlarge]

This artist’s impression shows the free-floating planet CFBDSIR J214947.2-040308.9. This is the closest such object to the Solar System. It does not orbit a star and hence does not shine by reflected light; the faint glow it emits can only be detected in infrared light. Here we see an artist’s impression of an infrared view of the object with an image of the central parts of the Milky Way from the VISTA infrared survey telescope in the background. The object appears blueish in this near-infrared view because much of the light at longer infrared wavelengths is absorbed by methane and other molecules in the planet’s atmosphere. In visible light the object is so cool that it would only shine dimly with a deep red colour when seen close-up.

Credit: L. Calçada, P. Delorme, Nick Risinger, R. Saito, European Southern Observatory/VVV Consortium.

(Phys.org)—A planet that is not orbiting a star, effectively making it homeless, has been discovered by a team of University of Montreal (UdeM) researchers working with European colleagues and data provided by the Canada-France-Hawaii Telescope (CFHT) and the European Southern Observatory’s Very Large Telescope (VLT). “Although theorists had established the existence of this type of very cold and young planet, one had never been observed until today,” said Étienne Artigau, an astrophysicist at UdeM. The absence of a shining star in the vicinity of this planet enabled the team to study its atmosphere in great detail. This information will in turn enable astronomers to better understand exoplanets that do orbit stars.

Free-floating planets are planetary-mass objects that have no gravitational link to a star. “Over the past few years, several objects of this type have been identified, but their existence could not be established without scientific confirmation of their age,” explained Jonathan Gagné, a doctoral student of physics at UdeM. “Astronomers weren’t sure whether to categorize them as planets or as Brown dwarfs. Brown dwarfs are what we could call failed stars, as they never manage to initiate nuclear reactions in their centres.”

This closeup of an image captured by the SOFI instrument on ESO’s New Technology Telescope at the La Silla Observatory shows the free-floating planet CFBDSIR J214947.2-040308.9 in infrared light. This object, which appears as a faint blue dot at the centre of the picture, is the closest such object to the Solar System. Credit: P. Delorme, European Southern Observatory

Gagné and Artigau, along with Lison Malo and Loïc Albert, all of whom are astrophysicists with UdeM and the Centre for Research in Astrophysics of Quebec (CRAQ), were able to find this planet with the assistance of French astronomers. Philippe Delorme, of the Laboratoire d’Astrophysique de l’Observatoire de Grenoble, was lead researcher. The planet is in fact called CFBDSIR2149 and appears to be part of a group of very young stars known as the AB Doradus Moving Group. “This group is unique in that it is made up of around thirty starts that all have the same age, have the same composition and that move together through space. It’s the link between the planet and AB Doradus that enabled us to deduce its age and classify it as a planet,” Malo explained.

ESO.org have a video (for some unknown reason I could not link to it) that shows an artist’s impression of the free-floating planet CFBDSIR J214947.2-040308.9. In the first part of the sequence the planet appears as a dark disc in visible light, silhouetted against the star clouds of the Milky Way. This is the closest such object to the Solar System and the most exciting candidate free-floating planet found so far. It does not orbit a star and hence does not shine by reflected light; the faint glow it emits can only be detected in infrared light. In the final sequence we see an infrared view of the object with the central parts of the Milky Way as seen by the VISTA infrared survey telescope as background. The object appears blueish in this near-infrared view because much of the light at longer infrared wavelengths is absorbed by methane and other molecules in the planet’s atmosphere. In visible light the object is so cool that it would only shine dimly with a deep red colour when seen close-up. Credit: ESO/P. Delorme/Nick Risinger Click here to see the video.

First of all, the researchers obtained a series of infrared images of CFBDSIR2149 using the 3.6 metres in diameter CFHT. They then used the full strength of the 8 metres in diameter VLT to deduce its mass, its temperature, and of particular note, its age. The planet was found to be between 50 and 120 millions years old, with a temperature of approximately 400 degrees celsius, and a mass four to seven times that of Jupiter. Objects more than 13 times the mass of Jupiter are not considered to be planets but rather Brown dwarfs, as it is this is the minimum amount of mass required for the deuterium at the heart of a star to achieve fusion.

As an aside, it is interesting to note the significance of the finding in terms of the roots of the word “planet.” “Planet as a word originates from the Latin word planetus, which originally comes from the Greek words planeta or planêtês, meaning moving or wandering celestial bodies, as opposed to stars which appeared to be in a fixed position in the sky,” said Oliver Hernandez, an astrophysicist at UdeM. In short, this is the first isolated planet – perhaps flung away during its formation – that is not tied by gravity to a star and whose mass, temperature and age meet the relevant criteria. This discovery, which has been sought after for more than a decade, supports theories relating to the formation of stars and planets. Moreover, it supports theories that suggest that these kinds of isolated objects are much more numerous than currently believed. “This object was discovered during a scan that covered the equivalent of 1000 times the surface of the full moon,” Artigau explained. “We observed hundreds of millions of stars and planets, but we only found one homeless planet in our neighbourhood. Now we will be looking for them amongst an astronomical number of sources further afield. It’s like looking for a single needle in amongst thousands of haystacks.” More information: This research is presented in a paper, “CFBDSIR2149-0403: a 4-7 Jupiter-mass free-floating planet in the young moving group AB Doradus?” to appear in Astronomy & Astrophysics on 14 November 2012. (PDF)

Original article at http://phys.org/news/2012-11-astronomers-homeless-planet-space.html

So did this article remind you of anyone?

No, you’re right. I guess I have spent a bit too long with children’s television on in the background!