News Article | November 19, 2015
The world will hold onto its leap second, at least until 2023. The International Telecommunication Union, a part of the United Nations, decided on Thursday at the World Radiocommunication Conferences that it would delay its decision on whether to abolish the leap second so that potential effects of its elimination can be studied. The leap second is an extra second of time added periodically to the world’s clocks, but some experts have raised fears it could throw off modern technology, including banking systems, GPS, flight operators, and more. The adjustment is meant to compensate for the differences between traditional solar time, based on the rate that the earth spins, and time kept by the world’s hyper-accurate atomic clocks, which measure time by cesium atomic frequency. Without adding a leap second every few years, the time on our computers and phones would very slowly drift out of sync with the rising and setting cycle of the sun. An extra second has been added every few years since 1972—the last one happened this summer—but the practice has been increasingly under scrutiny. Demetrios Matsakis, Chief Scientist for Time Services at the US Naval Observatory, told Motherboard earlier this year the leap second puts untold numbers of systems at risk for failure. "We should eliminate leap seconds because of the real-world practical impossibility of reliably implementing them, due to either their inherent nature or to general lack of knowledge of their very existence," he said at the time. Other countries, including France, Italy, and Japan also oppose the leap second, while Russia and Britain support it. All countries were supposed to come to a mutual decision on a course of action during this year’s ITU meeting, said Sanjay Acharya, a spokesperson for the ITU. “If not everybody agrees, systems won't function in any case, so we do strive for consensus in decisions like these,” he said. “There are very strong positions on either side of this so therefore the decision at this time was to delay the decision until 2023.” The next ITU World Radiocommunication Conference is in 2019, but the decision will be delayed until the following meeting, pending studies. These studies will be conducted by the ITU with other organizations, including the General Conference on Weights and Measures (CGPM), the International Committee for Weights and Measures (CIPM), the International Bureau of Weights and Measures (BIPM), the International Organization for Standardization (ISO), and the World Meteorological Organization (WMO). Leap seconds always fall at the end of June or December, but the next leap second has not yet been announced. Time will tell how many more of them remain in our future.
News Article | March 10, 2016
The technology includes a new class of radio antenna and electronics that provide broadband capabilities for Very Long Baseline Interferometry, or VLBI. This technique is used to make precise measurements of Earth in space and time. VLBI measurements have been conducted for decades using a worldwide network of stations that carry out coordinated observations of very distant astronomical objects called quasars. To meet the demand for more precise measurements, a new global network of stations, called the VLBI Global Observing System, or VGOS, is being rolled out to replace the legacy network. NASA is participating in this next-generation network and just completed the installation of a joint NASA-U.S. Naval Observatory VGOS station at NASA's K?ke'e Park Geophysical Observatory in Hawaii. NASA has two other developmental VGOS stations operating at the Goddard Geophysical and Astronomical Observatory at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and at the Massachusetts Institute of Technology's Haystack Observatory in Westford, Massachusetts. With this preliminary network, NASA passed a crucial milestone on February 5: conducting the first demonstration anywhere in the world of broadband observations for VLBI over a long baseline. "The successful tests demonstrate the viability of the new broadband antenna technology for making the kinds of observations needed for improved accuracy in measurements of the very fine-scale shape of Earth," said Benjamin R. Phillips, who leads NASA's Earth Surface and Interior Focus Area at NASA Headquarters in Washington, D.C. The coordinated observation was verified by detection of fringes - an interference pattern indicating that all three stations were receiving and could combine the signals from the quasar they observed. "The testing has been a concerted effort involving many team members at all three stations, as well as the MIT correlator facility," said Pedro Elosegui of the Haystack Observatory, which leads the NASA development of the VGOS signal chain. Several technical hurdles had to be cleared to carry out the long-baseline demonstration. One issue is that the effects of the ionosphere - a layer of Earth's upper atmosphere that impacts the behavior of radio waves - and of the local weather are quite different at the three sites. Another factor, which applies in any VLBI measurement, is that stations have to contend with interference from nearby radio and cell towers and other sources. "These and other technical issues have been dealt with," said Goddard's Stephen Merkowitz, manager of NASA's Space Geodesy Project. "We have a few more challenges down the road, but they are manageable. We now know that the new global system can be used the way it was intended." The broadband antenna and electronics provide improved sensitivity in a scaled-down package. With dish sizes of 12 to 13 meters (about 39 to 42 feet), the next-generation antennas are designed to be smaller than most of the current system's dishes, which are typically 20 to 30 meters (about 65 to 100 feet). The scaled-down size allows an antenna to move quickly, conducting up to 100 observations in an hour compared to about 12 observations in an hour for the current VLBI system. This type of antenna is also much less expensive than the larger antennas, making it more economical to deploy and operate a global network. Broadband capability makes it possible to conduct observations in four bands - that is, at four frequencies - at the same time, whereas current VLBI systems operate in two bands. With four bands, more bits can be recorded at once, so the broadband system can achieve data rates of 8 to 16 gigabits per second, which is about 1000 times the data rate for HDTV. (The current VLBI system has a typical rate of 256 megabits per second.) This leads to better sensitivity, even though the antenna is smaller. Another new feature is that the four bands are selectable within a range of 2 gigahertz to roughly 14 gigahertz. This helps to avoid interference with other sources, such as radio and cellphone towers. With the rollout of the VGOS network, existing VLBI stations are being replaced, or in some cases upgraded. More sites will be added in the future to provide more uniform coverage across the globe. Once fully implemented, the worldwide VGOS network is expected to yield position and Earth orientation measurements that improve precision by a factor of three or more, compared to current measurements. "The next-generation VLBI system will expand our ability to make the kinds of measurements that will be needed for geophysical studies and navigation applications, which demand more precision all the time," said Merkowitz. Explore further: NASA pinning down 'here' better than ever
News Article | December 1, 2016
You may not know the name Dr. Patrick Soon-Shiong, but the White House certainly does. Earlier this year, Vice President Joe Biden tapped the billionaire surgeon and biotech entrepreneur to advise the Obama Administration's Cancer Moonshot program to develop genetically tailored cures for the diseases. On November 19, the man Biden described as a "brilliant, sometimes controversial guy" had dinner with two other controversial guys, President-elect Donald Trump and Vice President-elect Mike Pence. Of the meeting at Trump's New Jersey golf course, the transition team said in a statement that the trio discussed "innovation in the area of medicine and national medical priorities that need to be addressed in our country." Soon-Shiong (who donated $50,000 to Hillary Clinton's campaign effort, according to the FEC) thinks big, puts himself at the center of issues, and doesn't mind taking credit for things he isn't wholly responsible for (like the advancement of immune-based therapies). "I'm sort of this doctor with a complete scientific bent," Soon-Shiong told Fast Company in one of several conversations from the past few months. Though many experts have been working to harness the body's own immune system to fight off cancer, Soon-Shiong's name has been widely associated with the concept. "Maybe in my lifetime, we can maybe find a way to cure cancer," he says. The 64-year-old surgeon and entrepreneur has made a fortune and won praise for his health tech ventures, such as creating Abraxane, the targeted chemotherapy for breast cancer that made him a billionaire. (Forbes estimates his net worth at $9.8 billion.) But he's also drawn warnings from federal regulators, spurred lawsuits, and received a skeptical reaction from some peers in the medical community. While aiding the government's Cancer Moonshot program, Soon-Shiong also launched his own private-sector effort with the confusingly similar name Cancer MoonShot 2020. It's an outgrowth of his company NantWorks, a conglomerate of firms that aims to play a role in every aspect of cancer research and treatment, from genetic testing and analysis to chemotherapy development to hospital information systems to immunotherapies. He says that immune-system treatments might tackle catastrophic viral infections like Zika and Chikungunya, too. Instead of assaulting the patient's body with devastating blows of toxic chemicals or radiation, Soon-Shiong advocates coaxing its immune system to discretely attack just cancer cells—the way it does so effectively against invaders like viruses and harmful bacteria. This requires priming the immune system, like with a vaccine developed from the defective proteins in a patient's own tumors, what Soon-Shiong calls neoepitopes. "So it's like an infection," he says. "So think of . . . treating yourself for flu or treating yourself for strep throat." Cancer research has been heading in this direction for years, and Soon-Shiong is an eloquent advocate of the approach. In March, at the Future of Genomics conference in San Diego, cardiologist and geneticist Eric Topol interviewed Soon-Shiong in front of some of the world’s top genetics and cancer researchers after the billionaire’s keynote address. "Nobody could ever accuse you of not thinking big," Topol said. "You're basically this portal from challenging dogma to building hope." Like Trump, Soon-Shiong has made bold promises that beget skepticism. "These guys that make wild claims are inherently not to be trusted. We’re told in the scientific community that the data should speak for itself," says Dr. Ethan Weiss, a cardiologist and professor at the UCSF School of Medicine, when asked about Soon-Shiong's bold assertions. "He’s a hype merchant propping up a lucrative empire with almost no real substance," tweeted Daniel MacArthur, a genetics researcher at Massachusetts General Hospital, regarding Soon-Shiong's meeting with Trump. (MacArthur later deleted his Tweet, telling Fast Company over Twitter, "It was an ill-advised joke that was taken out of context—now deleted.") In 2014, a thorough profile of Soon-Shiong by Matthew Herper in Forbes surfaced a common complaint among medical experts: the doctor's penchant for pushing dramatic claims over details. He promised, for example, that in just 47 seconds, NantWorks' total health solution would be able to analyze a cancer patient's genetic makeup from a blood sample and recommend the specific protein to be targeted by medications. That was based on an average calculation for the efficiency of the entire computing system. The actual time Soon-Shiong was targeting for a real patient, Herper noted, would be about 24 hours—still very quick. "Which raises the question: Why the unnecessary, counterproductive hyperbole?" Herper wrote. "How easy it could have been to instead take a bow for the hardware and the high-speed data connections he has built." Legal controversies follow Soon-Shiong. He's been sued by employees and shareholders, with allegations of fraud; companies associated with him have been cited by the FDA for safety violations and making unsubstantiated medical claims. Soon-Shiong's ambitions are huge and his rhetoric sometimes gets him in trouble. But given the success he's already achieved, he’s not likely to change his approach anytime soon. Born in South Africa in 1952 to a healer who specialized in traditional Chinese herbal medicine, Soon-Shiong earned his medical degrees in Johannesburg and Vancouver. Shortly after joining UCLA Medical School in 1983, he directed the university’s pancreas transplant program and became famous for performing the first pancreas transplant on the West Coast. He's married to actress Michelle B. Chan (best known for her role in '80s series MacGyver), owns one of the largest homes in L.A., and purchased Magic Johnson's share of the L.A. Lakers. In May, he invested $70.5 million in Tribune Publishing, the newspaper group that owns the Los Angeles Times and the Chicago Tribune. The deal includes Soon-Shiong giving Tribune access to 100 technology patents that the doctor says will allow more interactive and immersive experiences for readers. Details remain vague. Soon-Shiong built his fortune by developing Abraxane, a reformulation of an existing chemotherapy treatment for breast cancer, paclitaxel (the generic form of Taxol). As explained in the original research paper, Soon-Shiong encapsulated paclitaxel in albumin, a common protein, making it more effective at penetrating the affected tissue. "When I launched Abraxane, they said Abraxane was just another Taxol generic," Soon-Shiong says of critics in the cancer field, adding that "they had no appreciation" for the mechanism it used to access cells. The commercial success of Abraxane helped make Soon-Shiong one of the richest people in his adopted hometown of Los Angeles. (Some estimates have him as the richest person.) Though he speaks about disease as a battle or war, Soon-Shiong criticizes the scorched-earth practice of traditional high-dose chemotherapy. "My job over the next five years is to break that," he says. Despite his claim to be leading the charge, the truth is, over the past decade, the oncology community as a whole has already been moving away from heavy-dose chemo and towards-immune system-based treatments. "Immunotherapy, after a long and difficult struggle over decades, has emerged as one of the most exciting developments in cancer in a long time," said Dr. Francis Collins, director of the National Institutes of Health in a briefing with reporters on the government's Cancer Moonshot back in January. The latest criticism of Soon-Shiong is that he has fed on the publicity associated with federal government anticancer work. On January 11, the morning before Barack Obama's final State of the Union Address in which the president announced the government's National Cancer Moonshot, Soon-Shiong held a webcast with a group of powerful allies in the medical world to announce the private sector-led Cancer MoonShot 2020. (A press release had gone out the day before.) "This is very much what we call a 'do tank,'" Soon-Shiong said. "It’s not a think tank." The initiative’s ambitious goal is to enroll 20,000 patients, covering 20 types of tumors, in clinical trials that lead to FDA-approved treatments by 2020—a blink of an eye in the slow, methodical world of medical research. Following the live webcast, Soon-Shiong released a multicam video of the event overlaid with inspirational background music. "The essence of the goal is to move something that would normally take five years, 10 years, 20 years, into a highly ambitious goal, having it done by 2020," Soon-Shiong says. But the timing of Soon-Shiong's announcement rankled some, leading to claims that he intentionally scooped the president of the United States. At the very least, didn't he create confusion between the two similarly named efforts? "I had no idea what they were going to announce at the State of the Union," he says. In reference to MoonShot 2020, he adds, "All of that was planned one year in advance. We initiated this in 2014." Soon-Shiong claims to have a close relationship with and to bear some influence on Vice President Biden, whom he first met while Biden was seeking advice for his son Beau during Beau's struggle with brain cancer. (He died in May 2015.) Soon-Shiong takes credit for introducing the "moonshot" concept to Biden months before the State of the Union address. And when he talks about this transaction, he is very specific about the details. "By October, I gave [Biden] a white paper that talked about the moonshot," he told the audience in San Diego. "By November, he visited us, and by December, he invited me to present this entire program." The presentation took place on December 1, 2015, at Biden's residence at the U.S. Naval Observatory; Soon-Shiong invited many people who would become members of his private MoonShot 2020, including Independence Health Group CEO Dan Hilferty and Columbia University researcher Dr. Azra Raza. Some supporters of MoonShot 2020 come from universities and research centers. Staff from government institutes such as Walter Reed Medical Center and the National Cancer Institute (NCI) have also attended meetings or released statements of support—but they did so strictly as individuals, not as official representatives of their respective institutions. "We're looking for people doing the work. This is not about a name thing," Soon-Shiong says. Still, according to the industry newsletter The Cancer Letter, government officials asked Soon-Shiong to take all mentions of federal agencies off the press release announcing his initiative. The creation of Abraxane is the central element of Soon-Shiong's origin story: It provided the personal vindication and wherewithal for the doctor to build his anticancer empire and shoot for the moon. The FDA's approval of Abraxane in 2005 allowed Soon-Shiong to fund a complex multibillion-dollar web of companies under the umbrella group NantWorks that target the entire cancer-care life cycle—including computing and artificial intelligence used to collect and analyze medical data. NantWorks also branches into other areas, like managing patient electronic health records. NantWorks even owns a sound studio near its headquarters in Culver City, where neighbors include Sony Pictures. According to the company website: Even the company name is multifaceted and hard to pin down. "'Nant' is nantan, which is the Native American that speaks for the people," Soon-Shiong explains. "'Nant' could be nanotechnology, 'Nant' could be neural network. 'Nant' is new approaches to neoepitope therapy." The goal is to make Nant the "Bell Labs of health care," he says, referencing the great research institution founded by AT&T in 1925 and now part of Alcatel-Lucent. The NantWorks accounting is complex, with money moving back and forth between entities. For instance, In 2010, Soon-Shiong sold Abraxis BioScience (the maker of Abraxane) for $2.9 billion to Celgene. (Soon-Shiong was the largest individual shareholder in both companies, according to Forbes.) Then in 2014, Celgene put money back into NantWorks by investing $25 million in NantHealth and $75 million in NantBioScience, a Soon-Shiong company developing more chemotherapies. Health care IT company Allscripts purchased a 10% equity stake in NantHealth for $200 million in cash, while Soon-Shiong invested $100 million in Allscripts. (Meanwhile, a Celgene lobbyist is reportedly on Trump's transition team.) One of NantHealth's projects is GPS Cancer, a reading of a patient's genome (DNA), transcriptome (RNA), and proteome (proteins) to develop targeted treatments for specific tumors. "So it's like a target, right?" he says. "GPS-ing your cancer." That's expensive, up to $50,000 per patient, but according to Soon-Shiong, in the long run, it's a cheaper treatment if the technique can someday cure the patient's cancer, when more advanced chemo- and immunotherapies become available. Independence Blue Cross was the first health insurance provider to cover GPS Cancer, which Soon-Shiong says was the trigger for formally launching MoonShot 2020. (Other insurance carriers have since come aboard, such as South Dakota-based Sanford Health Plan.) There are links between these entities: An affiliate of Independence was a minority owner of NaviNet, which provides a portal linking physicians and insurance providers. NantHealth purchased NaviNet in January. As if dominating cancer care weren't ambitious enough, NantHealth also aims to transform electronic health record keeping with software that collects and consolidates data from hospital devices like vital signs monitors and dialysis machines. Another offering gathers data from blood pressure cuffs and other home-care machines. The company promises that another product, NantOS, "will bring together the clinical, financial, operational, and environmental data to identify and solve complex health care problems such as quality, cost, and outcomes at a health system level, hospital level, service line level, physician level, and the patient level." NantHealth went public in June of this year for a valuation of about $1.5 billion. In July, Soon-Shiong's NantKwest, which is dedicated to activating the immune system's "natural killer" cells to fight cancer, had a public offering valued at $2.6 billion. In an interview with Bloomberg, Soon-Shiong said that he had two more IPOs in the pipeline for other companies in the Nant umbrella: NantBioscience and diagnostic company NantOmics. Soon-Shiong's recent IPOs provide a glimpse into the discord that follows him and his businesses. The Securities and Exchange Commission filing for NantHealth made quick mention of a whistleblower lawsuit. Two fired executives, Stephanie Davidson and William Lynch, filed a wrongful termination suit alleging that they were let go for calling attention to shortcomings and fraudulent activities, including the violation of health privacy requirements. Fast Company's calls to their attorney, Mitchel L. Feldman, have not been returned. Meanwhile, NantKwest was hit in June with a class-action lawsuit from investors. Plaintiffs say the company made false and misleading financial statements, in part due to high stock-based awards given to Soon-Shiong. In July 2015, NantHealth parted ways with its first customer, Providence Health and Services, where Soon-Shiong also served as global director of cancer services and bioinformatics. In an announcement, he said the 27-hospital system’s leadership "is not ready to blur science and clinical practice." Controversies are nothing new for Soon-Shiong, and they haven't slowed him down. In 2006, he received a warning letter from the FDA that called out "significant" deficiencies at the Abraxis Bioscience manufacturing facility in Illinois that led to microbiological contamination. The letter also chastised Soon-Shiong's slow response to remedy the problem. None of this seems to have hurt his lucrative 2010 sale of Abraxis to Celgene, after which controversy continued. In 2011, the FDA cautioned Celgene against making several unsubstantiated claims about Abraxane at an oncology conference. These included the assertion that Abraxane could treat other forms of cancer, such as non-small-cell lung cancer, for which it had not yet been approved. In 2012, the FDA did approve Abraxane for lung cancer treatment, vindicating the company's optimistic claims. (It also won approval for pancreatic cancer in 2013.) Abraxane could be a metaphor to describe Soon-Shiong's unconventional, sometimes confrontational, approach to both medicine and business. The doctor gives off a whiff of impatience with the world around him. Critics didn't understand the Abraxane breakthrough, he says, but they were proved wrong. Celgene started to brag about new uses of Abraxane before it had all the evidence in place, but ultimately, the FDA came around. Likewise, employees and shareholders have faulted Soon-Shiong's recent startups, but he's propelled the companies to multibillion-dollar valuations. There are parallels with the president-elect, who was continually underestimated over the past 18 months, right up to election night. Now it's time to see if each man can deliver the results he has promised.
News Article | September 8, 2016
What if GPS goes down? The National Institute of Standards and Technology (NIST) and the U.S. Naval Observatory (USNO), which operate U.S. civilian and military time standards, respectively, have worked with two companies—Monroe, Louisiana-based CenturyLink, and Aliso Viejo, California-based Microsemi—to identify a practical backup possibility: Commercial fiber-optic telecommunications networks. In GPS systems, transmissions can be disrupted unintentionally by radio interference or the weather in space, for instance. Various types of intentional interference are possible also. Federal agencies have long recognized the need to back up GPS, a collection of several dozen satellites that has provided users with time and position information since the 1970s. To explore the possibility of using commercial telecom networks as a backup for time services, an ongoing experiment connects the NIST time scales in Boulder, Colorado, with the USNO alternate time scale at Schriever Air Force Base in Colorado Springs by means of CenturyLink's fiber-optic cables. The two federal time scales, 150 kilometers apart, are ensembles of clocks that generate versions of the international standard for time, Coordinated Universal Time (known as UTC), in real time. In this experiment, time signals were sent at regular intervals in both directions between the two locations. Researchers measured the differences between the remote (transmitted) and local time. The results, just presented at a conference, showed UTC could be transferred with a stability of under 100 nanoseconds (ns, or billionths of a second)—thus meeting the project's original goal for this metric—as long as the connection remained unbroken. Stability refers to how well the remote and local clocks remain synchronized. Because the signals were forwarded by various pieces of equipment along each path, they experienced significant unequal delays in the two different directions. This reduced overall performance, resulting in an accuracy that did not meet the stated goal of 1 microsecond (millionths of a second). With the GPS available to calibrate (and thus correct for) the unequal delays, time transfer could be accomplished maintaining that calibration within 100 ns if GPS were to "disappear," the study suggests. "The 100 ns stability level is good enough to meet a new telecommunications standard," said lead author Marc Weiss, a mathematical physicist at NIST. "We'll continue trying to meet the 1 microsecond accuracy level, which is needed by critical infrastructure such as the power industry." The conference paper notes that if the fiber-optic network or its power source went down and had to be re-established, then GPS or some other alternative time reference would be needed to recalibrate the fiber-optic circuit. The authors suggest the fiber network could serve as a partial backup to the GPS, and the GPS could be used for calibration to correct timing delays. Or, to provide a more reliable backup for the GPS, two independent telecom network paths could be used. In the experiment, fiber-optic cables run from NIST and USNO to their respective nearby CenturyLink offices, where the signals are multiplexed into the network on a dedicated wavelength not shared with any other customers. The experiment began in April 2014 and will run through the end of 2016. "It appears that there is at least one commercial transport mechanism that could serve to back up GPS for time transfer at the 100 ns level," the paper concludes. "We have some certainty that similar results will apply if this technique were used as a service across the country." The need for precision timing backup has grown along with the importance of GPS. According to a 2013 study by the Government Accountability Office, "GPS is essential to U.S. national security and is a key component in economic growth, safety, and national critical infrastructure sectors." An inability to mitigate GPS disruptions could result in billions of dollars in economic losses, the study found. Explore further: Atomic clock signals may be best shared by fiber-optics
News Article | December 29, 2016
Excited for the New Year? Unfortunately, you will have to wait a second longer for 2016 to end. A "leap second" will be added to the world's clocks on the last day of the year. The extra second is necessary because the rotation of the Earth is not regular. It sometimes speeds up and sometimes slows down because our planet "brakes" for ocean waves. U.S. Naval Observatory public affairs officer Geoff Chester explained that time was historically based on the mean rotation of our planet relative to celestial bodies and the second was defined based on this reference frame. The advent of atomic clocks paved way for a more precise atomic timescale. Unfortunately, discrepancy would eventually occur between the astronomical time, which is based on the length of one Earth day, and the atomic time, which is measured by about 400 atomic clocks around the world. The Earth decelerates because of the braking action of ocean tides caused by the gravitational forces of the moon. As a result, the Earth's rotation gradually slows compared with atomic clocks. The astronomical time gradually falls out of sync with atomic time. Leap seconds have been added when needed since 1972 to reconcile the difference between the two systems. "Leap seconds are added in order to keep the difference between UTC and astronomical time (UT1) to less than 0.9 seconds," the National Institute of Standards and Technology of the U.S. Department of Commerce said. "Usually leap seconds are added when UTC is ahead of UT1 by 0.4 seconds or more." If leap seconds were not added, there would be a difference of up to three minutes by 2100 and a 30-minute difference by 2700. Although the additional second does not seem to have much effect on an average person, it can be critically important for some digital systems that are used today such as telecommunication. In July 2012, a leap second caused problem on popular websites and social media sites such as Reddit, Instagram, Pinterest and Netflix. Time discrepancies could also affect systems beyond Earth. "Think about Juno in orbit around Jupiter," Jean Dickey, from Jet Propulsion Laboratory, has explained. "With all our antennas on Earth, an error in time means an error in Earth rotation, which would end up being a navigation error. It could really wreak havoc with the mission." © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | October 26, 2016
Step aside, alien megastructure. It seems that the behaviour of an oddity known as Tabby’s star – which some have speculated may be caused by a massive extraterrestrial construction project – might in reality be explained by interstellar junk. KIC 8462852, as it is more officially called, was spotted by NASA’s Kepler space telescope, which recently spent four years carefully watching the same patch of sky and looking for any stars that dipped in brightness at regular intervals. These dips, which can be as large as 1 per cent, happen when an exoplanet crosses in front of a star. But Tabby’s star dimmed randomly, and by as much as 20 per cent, leaving astronomers dumbfounded – and leading to the speculation that an alien megastructure was responsible for the signal. Now Valeri Makarov at the US Naval Observatory in Washington DC and Alexey Goldin at Teza Technologies in Chicago, Illinois, have taken a closer look at the smallest of the star’s dips in light – only to find that Tabby’s star isn’t responsible for them. Whenever the small dips occur, there is also a slight jump in the position of the light, leading them to conclude that it is actually a different star along the line of sight that is dimming. Tabby’s star is still responsible for the largest dips in light, however. If more than one star is dimming, say Makarov and Goldin, then the culprit for the erratic behaviour can’t be an asteroid belt, debris from a smash-up between two larger bodies, or an alien megastructure around Tabby’s star. In fact, it can’t be anything around Tabby’s star alone. Instead, it has to be something lying between us and them. The pair speculate that this something may be a swarm of “interstellar comets”. These objects are created in star-forming regions, says Makarov, and when those objects move apart over time, all the stars and comets become scattered. “So maybe interstellar space is full of free-floating comets,” he says. “But try to find them! They are dark and cold, and travelling from nowhere to nowhere, basically, forever.” “If this is right, then that conclusion is dead on,” says Jason Wright at Pennsylvania State University, who postulated the alien megastructure in the first place – although he notes that comets are usually defined by their proximity to a star, so calling them “interstellar comets” doesn’t make sense. A second dimming star automatically leads to an interstellar explanation, he says. Wright himself had lately come to a similar conclusion. The latest evidence shows that not only does Tabby’s star dim sporadically, but it also appears to have been gradually fading for a century. Wright thinks that only an interstellar cloud passing in front of the star could explain such long-term dimming. But, he concedes, “we don’t know of any such cloud along the line of sight”, and observing one directly will be tricky. Instead, Makarov thinks our best chance is to wait a decade or so until the blended, second star has moved away from Tabby’s star and we can catch the intruder red-handed.
Jorgensen A.M.,New Mexico Institute of Mining and Technology |
Schmitt H.R.,Computational Physics, Inc. |
Van Belle G.T.,Lowell Observatory |
Mozurkewich D.,Seabrook Engineering |
And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
Optical Interferometry has long been limited by low SNR making it nearly impossible to measure the small visibilities required to make resolved images. Although the SNR exists in the raw data, much SNR is lost in the conventional squared-visibility processing. In modern interferometers fringes are recorded simultaneously at many wavelengths and baselines. This makes phase-referencing possible, which is the key to coherent integration, which in turns can greatly improve the SNR of measurements, making small-amplitude resolving measurements possible. In this paper we will detail the theory of coherent integration. We will also explain why coherent integration should, in most cases, be carried out during post-processing in software rather than in real-time in hardware. We will then compare it to conventional processing approaches for some data from the Navy Optical Interferometer. We will demonstrate how coherent integration can improve the accuracy of observations. © 2012 SPIE.
Ryan K.K.,New Mexico Institute of Mining and Technology |
Jorgensen A.M.,New Mexico Institute of Mining and Technology |
Hall T.,New Mexico Institute of Mining and Technology |
Armstrong J.T.,U.S. Navy |
And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012
The Navy Precision Optical Interferometer (NPOI) has now been recording astronomical observations for the better part of two decades. During that time period hundreds of thousands of observations have been obtained, with a total data volume of multiple terabytes. Additionally, in the next few years the data rate from the NPOI is expected to increase significantly. To make it easier for NPOI users to search the NPOI observations and to make it easier for them to obtain data, we have constructed a easily accessible and searchable database of observations. The database is based on a MySQL server and uses standard query language (SQL). In this paper we will describe the database table layout and show examples of possible database queries. © 2012 SPIE.
Jorgensen A.M.,New Mexico Institute of Mining and Technology |
Schmitt H.,U.S. Navy |
Schmitt H.,Computational Physics, Inc. |
Armstrong J.T.,U.S. Navy |
And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010
In this paper we will discuss the current status of coherent integration with the Navy Prototype Optical Interferometer (NPOI).1 Coherent integration relies on being able to phase reference interferometric measurements, which in turn relies on making measurements at multiple wavelengths.We first discuss the generalized group-delay approach, then the meaning of the resulting complex visibilities and then demonstrate how coherent integration can be used to perform very precision measurement of stellar diameters. The phase of the complex visibility is particularly attractive as a data product because it is not biased in the same way as visibility amplitudes. We discuss the relative SNR of triple-product phases and single-baseline phases. We then demonstrate how singlebaseline phases can be used to make accurate measurements of magnitude differences and separations of binary stars. © 2010 SPIE.
News Article | November 2, 2015
The clocks turned back an hour on Sunday, Nov. 1, while many of us were still out celebrating Halloween. While we should be happy that we gained an hour of sleep, it's hard to ignore the fact that this comes at a price. With the end of Daylight Savings Time — when we push our clocks an hour ahead in the spring — it will be darker earlier now, a sign that winter is just around the the corner. This means many of you will be leaving for work pre-dawn and coming back home sans the sun. However, while it might feel like we are continuously living in darkness, how much daylight is really left after the day that time falls back? Keith Collins from Quartz put together this handy interactive visual, using data from the Astronomical Applications Department of the U.S. Naval Observatory to show just that. The data assumes you are located in New York, but Collins says that there are slight differences across the U.S. The visual shows how much light is present in blue and darkness in a dark gray, revealing that that today, there are only 10.40 hours of daylight. Users can scroll throughout the graph to see how much light there is year round. You can also enter in what time you wake up and what time you go to bed to see how much of the sun you will get to see. If you wake up at 6:30 a.m. and fall asleep by 11:30 p.m., you still only get a little more than 10 hours of light, although if you work in an office, it may seem like you never see the sun. June appears to provide the most sunlight, so we can keep dreaming of the months ahead. Check out how much Daylight Savings Time has an impact on you by clicking the link here.