Here’s Your First Look at the Most Detailed Simulation of the Cosmos Ever Made


The largest simulation of the cosmos ever run has boldly taken us where we have never gone before: the formation of the universe. Illustris: The Next Generation (IllustrisTNG) utilized new computational methods to achieve a first of its kind universe-scale simulation. The data-packed simulation has already fueled three papers, which were published Thursday, Feb 1, in the Monthly Notices of the Royal Astronomical Society.

The insights gleaned from the simulation have given researchers a new understanding of how black holes affect the distribution of the ever-elusive dark matter throughout galaxies. Not only could these powerful gravity wells be preventing older galaxies from producing new stars, they could also be influencing the emergence of cosmic structures.

A single simulation run required 24,000 processors and a timespan of more than two months. Germany’s fastest mainframe computer, the Hazel Hen machine at the High-Performance Computing Center Stuttgart, ran the simulation twice. “The new simulations produced more than 500 terabytes of simulation data,” Volker Springel, principal investigator from the Heidelberg Institute for Theoretical Studies, said in a press release. “Analyzing this huge mountain of data will keep us busy for years to come, and it promises many exciting new insights into different astrophysical processes.”

IllustrisTNG made these predictions by modeling the evolution of millions of galaxies in a representative region of a universe. The cube-shaped area has sides that are nearly 1 billion light-years long. In the previous version (called Illustris), the model area’s sides were only 350 million light-years long. The updated program also introduced some crucial physical processes that had not been included in previous simulations.

Verifiable Predictions

These updated features allowed IllustrisTNG to model a universe remarkably similar to our own. For the first time, the clustering patterns of the simulated galaxies demonstrated a high degree of realism in comparison to the patterns we see from powerful telescopes, such as those at the Sloan Digital Sky Survey.

If the program’s verifiable predictions about dark matter, galaxy formation, and magnetic fields continue to prove accurate, we’ll be able to put greater stock in the insights it provides about processes we haven’t been able to observe with even the most advanced telescopes.

“When we observe galaxies using a telescope, we can only measure certain quantities,” Shy Genel, a scientist at the Flatiron Institute’s Center for Computational Astrophysics who worked on the development of IllustrisTNG, said in the press release. “With the simulation, we can track all the properties for all these galaxies. And not just how the galaxy looks now, but its entire formation history.”

By mapping out the histories of model galaxies, we may get a glimpse of what the Milky Way looked like as Earth came into being. We could even get an idea of how our galaxy might evolve billions of years from now.

In the years to come, this simulation might prompt some astronomers to simply adjust their telescopes to look for newly predicted stellar processes. For example, the simulation of the cosmos predicted that galaxy collisions that form larger galaxies should produce faint stellar light. Specific details about where to look for this background glow could allow astronomers to confirm their theories about these intergalactic events.

NASA Is Testing the Telescope That Will Revolutionize Our View of the Cosmos


IN BRIEF

The James Webb Space Telescope, the highly anticipated successor of Hubble, recently successfully completed cryogenic vacuum testing. This round of testing is one of the last major milestones before the telescope is finally launched.

TELESCOPE TESTING

In 2017, the James Webb Space Telescope (JWST) successfully completed cryogenic vacuum testing that lasted for over 100 days, solidifying the instrument’s capabilities and potential as a full observatory. In a NASA media briefing on January 10, officials at the Johnson Space Center in Houston discussed these efforts and the magnitude of this successful testing. The “world’s largest space freezer,” as described by Mark Voyton, Webb telescope Optical Telescope Element and Integrated Science Instrument Module (OTIS) manager at Goddard, allowed the team to successfully test the instrument and its pieces at the extreme temperatures it will endure in its missions.

Additionally, this testing showed that all mirrors and instrument models were aligned, with the primary mirror’s 18 segments all operating as one monolithic mirror. The tests also allowed NASA to exercise operations as they would occur in orbit, confirm that the integrated fine guiding system can track a star through the optical system, and ensure that the telescope could maintain correct observatory pointing. This laundry list of successful testing puts the JWST right on schedule to move forward and open our eyes to previously unseen corners of the universe.

The Webb testing was completed in Chamber A, a thermal-vacuum test facility that was first made famous in testing the Apollo spacecraft. While the Apollo tests were completed with both extreme heat and cold in mind, the chamber was heavily modified for the JWST. The Apollo craft were tested at temperatures as low as 100 Kelvin, but with these modifications, testing commenced at temperatures as low as 40 Kelvin with no high-temperature testing.

The success of this testing is not only a significant milestone for the James Webb Space Telescope and its highly-anticipated 2019 launch; it’s also a testament to the human spirit. This cryogenic testing occurred 24/7 throughout Hurricane Harvey, uninterrupted, as its international teams worked together in a collaborative effort.

MOVING FORWARD

After the success of this testing, the JWST will be transported for integration into a complete observatory and to undergo final environmental testing before traveling to its launch site. While there was a delay that pushed the launch from 2018 to 2019, the telescope is currently right on track to successfully make its launch window.

Artist conception of the James Webb Space Telescope observing the cosmos.
Artist conception of the James Webb Space Telescope observing the cosmos. 

The capabilities of the JWST will far surpass anything that has been created before. This mammoth telescope, described by Voyton as “the world’s most magnificent time machine,” proved a piece of this capability in testing: it detected, with all four instruments, the light of a simulated star for the first time. The fine guidance subsystem was successful in not only generating the position of the light, but also in tracking its movement. This was a first in testing, and it shows the remarkable applications that this telescope will have.

Because it is an infrared telescope, as opposed to a visual light telescope like Hubble, the James Webb Space Telescope requires a cold environment such as the one it was tested in. This will allow it to observe light from some of the earliest moments of the universe. Additionally, it will give us clarity in viewing exoplanets that we’ve only before dreamed of, closely observing Earth-like planets that could hold the promise of solidifying the existence of extraterrestrial life.

It hasn’t even left Earth yet, but this phenomenal instrument continues to inspire.

Communicating Across the Cosmos.


The cover of the phonograph record on the Voyager 1 and 2 spacecraft, which contains an interstellar message encoded on a phonographic record.  The encoded instructions attempt to explain to extraterrestrials how to play the record.  Credit: NASA JPL

If extraterrestrial civilizations exist, the nearest is probably at least hundreds or thousands of light years away. Still, the greatest gulf that we will have to bridge to communicate with extraterrestrials is not such distances, but the gulf between human and alien minds.

In mid-November, the SETI Institute in Mountain View, California sponsored an academic conference on interstellar communication, “Communicating across the Cosmos“. The conference drew 17 speakers from a variety of disciplines, including linguistics, anthropology, archeology, mathematics, cognitive science, radio astronomy, and art. In this installment we will explore some of the formidable difficulties that humans and extraterrestrials might face in constructing mutually comprehensible interstellar messages.

Optical PAyload for Lasercomm Science (OPALS) Flight System, the first laser communication from space. Credit: NASA/JPL-Caltech.

If we knew where they were, and we wanted to, the information revolution has given us the capability to send an extraterrestrial civilization a truly vast amount of information. According to SETI Institute radio astronomer Seth Shostak, with broadband microwave radio we could transmit the Library of Congress, or the contents of the World Wide Web in 3 days; with broadband optical (a laser beam for space transmission) we could transmit this same amount of information in 20 minutes. This transmission would, of course, take decades or centuries to cross the light years and reach its destination. These truly remarkable capabilities give us the ability to send almost any message we want to the extraterrestrials. But transmitting capabilities aren’t the hard part of the problem. If the aliens can’t interpret it, the entire content of the World Wide Web is just a mountain of gibberish.

Many conference participants felt that the problems involved in devising a message that could be understood by a non-human mind were extremely formidable, and quite possibly insurmountable.

Having its own separate origin, extraterrestrial life could be different from Earthly life all the way down to its biochemical foundations. The vast diversity of life on Earth gives us little reason to think that aliens will look like us. Given the different conditions of another planet, and the contingencies of a different history, evolution will have produced a different set of results. For interstellar messaging to be possible at all, these results must include an alien creature capable of language, culture, and tool-making. But if these abilities are founded on a different biology and different perceptual systems, they might differ from their human counterparts in ways that we would find hard to even imagine. Looking to our own possible future development, we can’t even be sure that extraterrestrials will be biological creatures. They might be intelligent machines.

According to cognitive scientist Dominique Lestel, who presented at the conference, understanding extraterrestrials poses an unprecedented set of problems. We face all of the problems that ethologists (scientists who study animal behavior) face when they study perception and signaling in other animal species. These are compounded with all of the problems that ethnologists face when they study other human cultures. Lestel worries that humans might not be smart enough to do it. He wasn’t alone in that opinion.

Explanation of the symbols on the cover of the Voyager record Credit: NASA JPL

Linguist and conference presenter Sheri-Wells Jensen said that humans have created more than 7,000 different spoken and signed languages. No one knows whether all human languages sprung from a single instance of the invention of language or whether several human groups invented language independently. Given the ease with which children learn a language, many linguists think that our brain has a specialized language “module” underlying the “universal” grammar of human languages. These special features of the human brain might pose a formidable barrier to learning the language of a creature with a different brain produced by a different evolutionary history. An alien language might make demands on our short term memory or other cognitive abilities that humans would find impossible to meet.

When human beings talk to one another, they rely on a system of mutually understood conventions. Often gestures and body language are essential to conveying meaning. Conference presenter Klara Anna Capova, a cultural anthropologist, noted that interstellar messaging poses unique problems because the conventions to be followed in the message can’t be mutually arranged. We must formulate them ourselves, without knowing anything about the recipients. The intended recipients are distant in both time and space. The finite speed of light ensures that query and response will be separated by decades or centuries. With so little to go on, the message will inevitably reflect our cultural biases and motives. In 1962, the Soviet Union transmitted a message towards the planet Venus. It was in Morse code, and consisted of the Cyrillic characters “Lenin”, “CCCP” (USSR), and “MIR” (the Russian word for “peace”). But the posited Venusians couldn’t possibly have known the conventions of Morse code, the Cyrillic alphabet, human names, countries, or possible relationships between them, no matter how intimately familiar these things would have seemed to the Soviets. Whether they are meant to build national prestige, sell a product, or cause humans to think deeply about their place in the universe, interstellar messages play to a human audience.

Given the long timescales involved in interstellar messaging, many conference participants noted the parallels with archeology. Archeologists have learned quite a lot about past human cultures by studying the artifacts and symbols they have left for us. Still, archeological methodologies have their limits. According to conference presenter and archeologist Paul Wason, these limits have much to teach us about interstellar messaging. Certain meanings are accessible to archeological analysis and others aren’t, because we lack the contextual knowledge needed to interpret them. Neolithic cave paintings speak to modern investigators about the skill and abilities of the painters. But, because we don’t have the needed contextual knowledge, they don’t tell us what the paintings meant to their creators.

To interpret symbols used in the past, we need to know the conventions that related the symbols to the things they symbolized. Linguistic symbols pose special problems. To understand them, we need to know two different sets of conventions. First, we need to know the conventions that relate the script to the words of the spoken language. Second, we need to know how the words of the spoken language relate to the things and situations it refers to. It is a sobering thought for would-be exolinguists that no one has ever succeeded in deciphering an ancient script without knowing the language it was written in.

What does all this tell us about our fledgling attempts to devise messages for aliens? The phonograph record carried on the Voyager 1 and 2 spacecraft includes a moving message from then President Carter, encoded as English text. It reads in part: “We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe.”

Human archeologists have never deciphered linear A, the writing system of the ancient Minoan civilization, due to its apparent lack of association with any known language. Unfortunately, since extraterrestrials likewise lack contextual knowledge of any human language, it is almost certain that they could never discern the meaning of President Carter’s text. The team that developed the Voyager message, which included astronomers and SETI pioneers Carl Sagan and Frank Drake, were well aware of the problem. Carter was, most likely, made aware. Interstellar messages play to a human audience.

An inscription written around the inner surface of a cup in Linear A, a script used by the Minoan civilization that has never been deciphered.  Credit: Sir Arthur Evans, Scripta Minoa: The Written Documents of Minoan Crete

Is it possible for us to do better? Some off-beat ideas were proposed. Both astronomer Seth Shostak and designer Marek Kultys thought we might consider sending the sequence of the human genome. This idea was quickly shot down by a comment from the audience. Why send them a key, they said, if the aliens don’t have a lock. The metaphor is apt. DNA can only do its job as a constituent part of a living cell. Reading and implementing the genetic code involves numerous highly specialized enzymes and other cellular parts. Even if alien biochemistry and cell structure are generally similar to their Earthly counterparts, there are many features of Earthly biochemistry that appear to be quirky products of the history of life on Earth. The probability that they would repeat themselves precisely on another world are, for all practical purposes, nil. Without the context of an Earthly cell, the sequence of the human genome would be meaningless gibberish.

In the twenty first century, our ability to transmit and process information has become astounding, but we still don’t know how information conveys meaning. Is there even a glimmering of a hope that we can reach beyond the limitations of our humanity to convey meaning to an alien mind? In the final installment of this report, we’ll consider some possibilities

Carl Sagan on Science and Spirituality.


 “The notion that science and spirituality are somehow mutually exclusive does a disservice to both.”

The friction between science and religion stretches from Galileo’s famous letter to today’s leading thinkers. And yet we’re seeing that, for all its capacity for ignorance, religion might havesome valuable lessons for secular thought and the two need not be regarded as opposites.

sagan_life

In 1996, mere months before his death, the greatCarl Sagan — cosmic sagevoracious reader,hopeless romantic — explored the relationship between the scientific and the spiritual in The Demon-Haunted World: Science as a Candle in the Dark (public library). He writes:

Plainly there is no way back. Like it or not, we are stuck with science. We had better make the best of it. When we finally come to terms with it and fully recognize its beauty and its power, we will find, in spiritual as well as in practical matters, that we have made a bargain strongly in our favor.

But superstition and pseudoscience keep getting in the way, distracting us, providing easy answers, dodging skeptical scrutiny, casually pressing our awe buttons and cheapening the experience, making us routine and comfortable practitioners as well as victims of credulity.

And yet science, Sagan argues, isn’t diametrically opposed to spirituality. He echoes Ptolemy’s timeless awe at the cosmos and reflects on what Richard Dawkins has called the magic of reality, noting the intense spiritual elevation that science is capable of producing:

In its encounter with Nature, science invariably elicits a sense of reverence and awe. The very act of understanding is a celebration of joining, merging, even if on a very modest scale, with the magnificence of the Cosmos. And the cumulative worldwide build-up of knowledge over time converts science into something only a little short of a trans-national, trans-generational meta-mind.

“Spirit” comes from the Latin word “to breathe.” What we breathe is air, which is certainly matter, however thin. Despite usage to the contrary, there is no necessary implication in the word “spiritual” that we are talking of anything other than matter (including the matter of which the brain is made), or anything outside the realm of science. On occasion, I will feel free to use the word. Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light years and in the passage of ages, when we grasp the intricacy, beauty and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual. So are our emotions in the presence of great art or music or literature, or of acts of exemplary selfless courage such as those of Mohandas Gandhi or Martin Luther King Jr. The notion that science and spirituality are somehow mutually exclusive does a disservice to both.

Reminding us once again of his timeless wisdom on the vital balance between skepticism and openness and the importance of evidence, Sagan goes on to juxtapose the accuracy of science with the unfounded prophecies of religion:

Not every branch of science can foretell the future — paleontology can’t — but many can and with stunning accuracy. If you want to know when the next eclipse of the Sun will be, you might try magicians or mystics, but you’ll do much better with scientists. They will tell you where on Earth to stand, when you have to be there, and whether it will be a partial eclipse, a total eclipse, or an annular eclipse. They can routinely predict a solar eclipse, to the minute, a millennium in advance. You can go to the witch doctor to lift the spell that causes your pernicious anaemia, or you can take vitamin Bl2. If you want to save your child from polio, you can pray or you can inoculate. If you’re interested in the sex of your unborn child, you can consult plumb-bob danglers all you want (left-right, a boy; forward-back, a girl – or maybe it’s the other way around), but they’ll be right, on average, only one time in two. If you want real accuracy (here, 99 per cent accuracy), try amniocentesis and sonograms. Try science.

Think of how many religions attempt to validate themselves with prophecy. Think of how many people rely on these prophecies, however vague, however unfulfilled, to support or prop up their beliefs. Yet has there ever been a religion with the prophetic accuracy and reliability of science? There isn’t a religion on the planet that doesn’t long for a comparable ability — precise, and repeatedly demonstrated before committed skeptics — to foretell future events. No other human institution comes close.

Source: http://www.brainpickings.org