Behold NGC 6357, “cathedral To Massive Stars.” Credit: NASA, ESA And Jesús Maíz Apellániz (IAA,

Stellar Outburst Brings Water Snow Line Into View

ESO - European Southern Observatory logo. 13 July 2016

Artist’s impression of the water snowline around the young star V883 Orionis

The Atacama Large Millimeter/submillimeter Array (ALMA) has made the first ever resolved observation of a water snow line within a protoplanetary disc. This line marks where the temperature in the disc surrounding a young star drops sufficiently low for snow to form. A dramatic increase in the brightness of the young star V883 Orionis flash heated the inner portion of the disc, pushing the water snow line out to a far greater distance than is normal for a protostar, and making it possible to observe it for the first time. The results are published in the journal Nature on 14 July 2016.

ALMA image of the protoplanetary disc around V883 Orionis

Young stars are often surrounded by dense, rotating discs of gas and dust, known as protoplanetary discs, from which planets are born. The heat from a typical young solar-type star means that the water within a protoplanetary disc is gaseous up to distances of around 3 au from the star [1] — less than 3 times the average distance between the Earth and the Sun — or around 450 million kilometres [2]. Further out, due to the extremely low pressure, the water molecules transition directly from a gaseous state to form a patina of ice on dust grains and other particles. The region in the protoplanetary disc where water transitions between the gas and solid phases is known as the water snow line [3].

The star V883 Orionis in the constellation of Orion

But the star V883 Orionis is unusual. A dramatic increase in its brightness has pushed the water snow line out to a distance of around 40 au (about 6 billion kilometres or roughly the size of the orbit of the dwarf planet Pluto in our Solar System). This huge increase, combined with the resolution of ALMA at long baselines [4], has allowed a team led by Lucas Cieza (Millennium ALMA Disk Nucleus and Universidad Diego Portales, Santiago, Chile) to make the first ever resolved observations of a water snow line in a protoplanetary disc.

Shifting water snowline in V883 Orionis

The sudden brightening that V883 Orionis experienced is an example of what occurs when large amounts of material from the disc surrounding a young star fall onto its surface. V883 Orionis is only 30% more massive than the Sun, but thanks to the outburst it is experiencing, it is currently a staggering 400 times more luminous — and much hotter [5].

ALMA image of the protoplanetary disc around V883 Orionis (annotated)

Lead author Lucas Cieza explains: “The ALMA observations came as a surprise to us. Our observations were designed to look for disc fragmentation leading to planet formation. We saw none of that; instead, we found what looks like a ring at 40 au. This illustrates well the transformational power of ALMA, which delivers exciting results even if they are not the ones we were looking for.”

ALMA image of the protoplanetary disc around V883 Orionis

The bizarre idea of snow orbiting in space is fundamental to planet formation. The presence of water ice regulates the efficiency of the coagulation of dust grains — the first step in planet formation. Within the snow line, where water is vapourised, smaller, rocky planets like our own are believed to form. Outside the water snow line, the presence of water ice allows the rapid formation of cosmic snowballs, which eventually go on to form massive gaseous planets such as Jupiter.

Zooming on the protoplanetary disc around V883 Orionis

The discovery that these outbursts may blast the water snow line to about 10 times its typical radius is very significant for the development of good planetary formation models. Such outbursts are believed to be a stage in the evolution of most planetary systems, so this may be the first observation of a common occurrence. In that case, this observation from ALMA could contribute significantly to a better understanding of how planets throughout the Universe formed and evolved.

The protoplanetary disc around V883 Orionis (artist’s impression)

Notes: [1] 1 au, or one astronomical unit, is the mean distance between the Earth and the Sun, around 149.6 million kilometres.This unit is typically used to describe distances measured within the Solar System and planetary systems around other stars. [2] This line was between the orbits of Mars and Jupiter during the formation of the Solar System, hence the rocky planets Mercury, Venus, Earth and Mars formed within the line, and the gaseous planets Jupiter, Saturn, Uranus and Neptune formed outside. [3] The snow lines for other molecules, such as carbon monoxide and methane, have been observed previously with ALMA, at distances of greater than 30 au from the protostar within other protoplanetary discs. Water freezes at a relatively high temperature and this means that the water snow line is usually much too close to the protostar to observe directly. [4] Resolution is the ability to discern that objects are separate. To the human eye, several bright torches at a distance would seem like a single glowing spot, and only at closer quarters would each torch be distinguishable. The same principle applies to telescopes, and these new observations have exploited the exquisite resolution of ALMA in its long baseline modes. The resolution of ALMA at the distance of V883 Orionis is about 12 au — enough to resolve the water snow line at 40 au in this outbursting system, but not for a typical young star. [5] Stars like V883 Orionis are classed as FU Orionis stars, after the original star that was found to have this behaviour. The outbursts may last for hundreds of years. More information: This research was presented in a paper entitled “Imaging the water snow-line during a protostellar outburst”, by L. Cieza et al., to appear in Nature on 14 July 2016. The team is composed of Lucas A. Cieza (Millennium ALMA Disk Nucleus; Universidad Diego Portales, Santiago, Chile), Simon Casassus (Universidad de Chile, Santiago, Chile), John Tobin (Leiden Observatory, Leiden University, The Netherlands), Steven Bos (Leiden Observatory, Leiden University, The Netherlands), Jonathan P. Williams (University of Hawaii at Manoa, Honolulu, Hawai`i, USA), Sebastian Perez (Universidad de Chile, Santiago, Chile), Zhaohuan Zhu (Princeton University, Princeton, New Jersey, USA), Claudio Cáceres (Universidad Valparaiso, Valparaiso, Chile), Hector Canovas (Universidad Valparaiso, Valparaiso, Chile), Michael M. Dunham (Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA), Antonio Hales (Joint ALMA Observatory, Santiago, Chile), Jose L. Prieto (Universidad Diego Portales, Santiago, Chile), David A. Principe (Universidad Diego Portales, Santiago, Chile), Matthias R. Schreiber (Universidad Valparaiso, Valparaiso, Chile), Dary Ruiz-Rodriguez (Australian National University, Mount Stromlo Observatory, Canberra, Australia) and Alice Zurlo (Universidad Diego Portales & Universidad de Chile, Santiago, Chile). The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”. Links: Research paper: http://www.eso.org/public/archives/releases/sciencepapers/eso1626/eso1626a.pdf Photos of ALMA: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Atacama%20Large%20Millimeter/submillimeter%20Array For more information about ALMA, visit: https://www.eso.org/sci/facilities/alma.html Images, Text, Credits: ESO/Richard Hook/A. Angelich (NRAO/AUI/NSF)/ALMA (ESO/NAOJ/NRAO)/ALMA//L. Cieza/IAU and Sky & Telescope/Videos: ALMA (ESO/NAOJ/NRAO)/L. Cieza./ESO/Digitized Sky Survey 2/N. Risinger (skysurvey.org)/M. Kornmesser. Music: Johan B. Monell. Best regards, Orbiter.ch Full article

The maximum life span is a theoretical number whose exact value cannot be determined from existing knowledge about an organism; it is often given as a rough estimate based on the longest lived organism of its species known to date. A more meaningful measure is the average life span; this is a statistical concept that is derived by the analysis of mortality data for populations of each species. A related term is the expectation of life. Life expectancy represents the average number of years that a group of persons, all born at the same time, might be expected to live, and it is based on the changing death rate over many past years.

The concept of life span implies that there is an individual whose existence has a definite beginning and end. What constitutes the individual in most cases presents no problem: among organisms that reproduce sexually the individual is a certain amount of living substance capable of maintaining itself alive and endowed with hereditary features that are in some measure unique. In some organisms, however, extensive and apparently indefinite growth takes place and reproduction may occur by division of a single parent organism, as in many protists, including bacteria, algae, and protozoans. In order to consider life span in such organisms, the individual must be defined arbitrarily since the organisms are continually dividing. In a strict sense, the life spans in such instances are not comparable to those forms that are sexually produced.

There is a brief period during which it is impossible to say whether an organism is still alive, but this time is so short relative to the total length of life that it creates no great problem in determining life span.

Some organisms seem to be potentially immortal. Unless an accident puts an end to life, they appear to be fully capable of surviving indefinitely. This faculty has been attributed to certain fishes and reptiles, which appear to be capable of unlimited growth. Without examining the various causes of death in detail, a distinction can be made between death as a result of internal changes (i.e., aging) and death as a result of some purely external factor, such as an accident. It is notable that the absence of aging processes is correlated with the absence of individuality. In other words, organisms in which the individual is difficult to define, as in colonial forms, appear not to age.

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Convergence II

Jaxson Pohlman Photography

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at what point in history do you think americans stopped having british accents

Hello there

As you can already tell, I haven't been really active (at all) on this account. The reason for this, to be honest, was the fact that Tumblr became stale to me, and besides that, I was very busy with my study for the university entrance exam for a year.

All of this caused this account to be abandoned for 2-3 years, which really not what I wanted at all because I created this account to help people with study and have reliable sources of information.

But I'm back (yay), and I’m trying to get back and resurrect this account again. There will be a few changes (since I changed a lot in the last few years).

1. My love for science is still there and even stronger now because... *drum rolls*... I’m studying science at university now! More specifically, biotechnology major, planning on an immunology minor. So yes, besides primary astronomy contents, I'm planning on posting more biology stuff! 

-> The name of this blog changed: study-astronomy-ref to study-astronomy-biology-ref

2. If you don’t know, this account is member-based. Even though I will be more active in the next few months, I can't be 100% be sure about keeping the account active for too long because of personal jobs and study. I had recruit more members for this account a while ago, but it didn't end well.

-> So if anyone wants to contribute to this blog as a pure studyblr, message, please. There, of course, will be standards and I will select the best people to run this blog smoothly, educationally and actively. For the best to everyone!

3. To me, this account is for people (very communism). So besides the science news, findings and study references, slide in the DM if you want something more interesting on this blog (science art? some Q&A? other cool science stuff?). I would be very happy if this blog could reach more people with similar interest and it could be a fun, wholesome and interesting place for anyone that has a passion for science and study! Wooray!

Maybe that's all I have to say. Stay tuned for more contents!

Head up to the sky, aliens. Keep on curious.

MARTIAN STORMS - Seen in 1977 by the Viking 2 Orbiter

“Like its predecessor, the Viking 2 mission consisted of a lander and an orbiter designed to take high-resolution images, and study the Martian surface and atmosphere. Both the Viking 1 and 2 landers benefited greatly from their orbiting counterparts, which snapped images that helped mission controllers navigate the landers to safe landing sites.”

This particular image was taken by the Viking 2 Orbiter and shows a massive dust storm on the red planet. This spectacular storm can be seen on a global scale. The Viking 2 mission would end 3 years later on April 11, 1980.

Credit: NASA/JPL

Some galaxies have extremely bright cores, suggesting that they contain a supermassive black hole that is pulling in matter at a prodigious rate. Astronomers call these “active galaxies,” and Hercules A is one of them. In visible light, Hercules A looks like a typical elliptical galaxy. In X-ray light, however, Chandra detects a giant cloud of multimillion-degree gas (purple). This gas has been heated by energy generated by the infall of matter into a black hole at the center of Hercules A that is over 1,000 times as massive as the one in the middle of the Milky Way. Radio data (blue) show jets of particles streaming away from the black hole. The jets span a length of almost one million light years.  

Credit: X-ray: NASA/CXC/SAO, Optical: NASA/STScI, Radio: NSF/NRAO/VLA

Colourised footage of Benjamin, the last know Tasmanian Tiger (Thylacine).

Benjamin died on September 7th, 1936 in Hobart zoo. It is believed that he died out of neglect, as he was locked out of his shelter and was exposed to the searing hot sun and freezing cold night of Tasmania.

The Thylacine was one of the last large marsupials left on Australia (the other being the Kangaroo) after a great extinction event occurred around 40 thousand years ago. This extinction event, caused mainly by the arrival of humans, wiped out 90% of Australia’s terrestrial vertebrates, including the famous Megafauna.

The Thylacine was around 15-30kg (33-66lbs), were carnivorous, and had numerous similarities to other species like dogs, despite not being related and purely by chance, in a phenomenon known as convergent evolution (just like the ability to fly of bats and birds, despite following different evolutionary paths). Not only that, they could open their jaws up to 120 degrees, could hop around on two legs like a kangaroo, and both males and females had pouches.

Lastly in a cruel twist, the Tasmanian government decided to protect the Thylacine - just 59 days before the last one died, in a very notable case case of “Too little too late”. To date, many biologists believe that there are still Thylacine roaming the wild plains of Australia. 

I MADE AN ART MASTERPOST

Bodies:

how to draw arms

*Hands*

How To Draw Hands

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another hand tutorial

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draw knees

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Lots of Stuff

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Other (non-specific):

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I made this most for my own benefit to organize this stuff, and have no idea how to make a masterpost!

▪︎Copernican armillary sphere.

Date: 1807-1846 

Place of origin: Paris

From the source: Copernican armillary sphere from set of two armillary spheres and a celestial globe constructed in paper on pasteboard with metal fitments supported on a decorative mahogany baluster base. Shows planets out to Uranus, plus four asteroids, Ceres, Pallas, Juno & Vesta, first quarter 19th century.