Tag Archives: NSF

Adieu to Radio Astronomy at Arecibo

Peter Lobner, Updated 15 January 2021

The Arecibo Observatory (AO) on Puerto Rico has been out of service since 10 August 2020, when a three-inch auxiliary support cable slipped out of its socket and fell onto the fragile radio telescope dish below. Three months later, on 6 November 2020, a second cable associated with the same support tower broke, damaging nearby cables, causing more damage to the reflector dish, and leaving the radio telescope’s support structure in a weakened and uncertain state.

On 19 November 2020, the National Science Foundation (NSF) announced it has begun planning for decommissioning the 57-year old Arecibo Observatory’s (AO) 1,000-foot (305-meter) radio telescope due to safety concerns after the two support wires broke and seriously damaged the antenna.  You can read NSF News Release 20-010 at the following link: https://www.nsf.gov/news/news_summ.jsp?cntn_id=301674

The 1,000-foot (305-m) dish at Arecibo Observatory in better days, in Spring 2019. Source: AO/University of Central Florida (UCF)
The damaged Arecibo Observatory radio telescope in November 2020.  
Source: NSF
A view from under the damaged dish. 
Source: AO/University of Central Florida (UCF)

The NSF website for AO is at the following link:  https://www.naic.edu/ao/telescope-description

This website includes a timeline summarizing the most important discoveries made by AO since 1967: https://www.naic.edu/ao/legacy-discoveries

Not included in the NSF timeline is the 1974 first-ever broadcast into deep space of a powerful signal that could alert other intelligent life to our technical civilization on Earth. The 1,679 bit “Arecibo Message” was directed toward the globular star cluster M13, which is 22,180 light years away. The message will be in transit for another 22,134 years.

The Arecibo Message. Source:  SETI

You’ll find a description of the Arecibo Message on the SETI website here: https://www.seti.org/seti-institute/project/details/arecibo-message

A key capability lost is AO’s planetary radar capability that enabled the large dish to function as a high-resolution, active imaging radar.  You’ll find examples of AO’s radar images of the Moon, planets, Jupiter’s satellites, Saturn’s rings, asteroids and comets on the NSF website here:  https://www.naic.edu/~pradar/radarpage.html

More impressive than the still images were animations created from a sequence of AO radar images, particularly of passing asteroids.  The animations defined the motion of the object as it flew near Earth. As an example, you can watch the following short (1:07 minutes) video, “Big asteroid 1998 OR2 seen in radar imagery ahead of fly-by”:

The US still has a reduced capability for planetary radar imaging with NASA’s Deep-Space Network’s Uplink Array.

AO’s radio telescope dish was the largest in the world until 2016 when China completed its 500-meter (1,640-foot) FAST radio telescope. It looks like the torch was passed just in time.  You’ll find information on FAST here: https://lynceans.org/all-posts/chinas-five-hundred-meter-aperture-spherical-telescope-fast-will-be-the-worlds-largest-radio-telescope/

Arecibo was not part of the Event Horizon Telescope (EHT) Collaboration of worldwide radio telescopes that succeeded in imaging the shadow of a black hole in 2019.  You’ll find this story here: https://lynceans.org/all-posts/the-event-horizon-telescope-team-has-produced-the-first-image-showing-the-shadow-of-a-black-hole/

The 19 November 2020 NSF news release stated, “After the telescope decommissioning, NSF would intend to restore operations at assets such as the Arecibo Observatory LIDAR facility — a valuable geospace research tool — as well as at the visitor center and offsite Culebra facility, which analyzes cloud cover and precipitation data.”

Adieu to radio astronomy at Arecibo.

Update 1 December 2020: Arecibo radio telescope collapsed.

NPR reported, “The Arecibo Observatory in Puerto Rico has collapsed, after weeks of concern from scientists over the fate of what was once the world’s largest single-dish radio telescope. Arecibo’s 900-ton equipment platform, suspended 500 feet above the dish, fell overnight after the last of its healthy support cables failed to keep it in place. No injuries were reported, according to the National Science Foundation, which oversees the renowned research facility.”

Arecibo after the collapse. Source: Ricardo Arduengo / AFP via Getty Images

Update 8 December 2020: National Science Foundation video shows the moment of collapse.

For more information:

A Newcomer at the Top of the June 2016 TOP500 Ranking of the World’s Supercomputers

Peter Lobner

The latest TOP500 ranking of the world’s 500 most powerful supercomputers was released on 20 June 2016. Since June 2013, China’s Tianhe-2 supercomputer topped this ranking at 33 petaflops [PFLOPS; 1015  floating-point operations per second (FLOPS)]. Now there is a new leader, and once again it is a Chinese supercomputer the Sunway TaihuLight.

sunway-taihulightSource: Jack Dongarra, Report on the Sunway TaihuLight System, June 2016

Details are available at the TOP500 website:

https://www.top500.org

On this website, Michael Feldman commented on the new leader in the TOP500 ranking:

“A new Chinese supercomputer, the Sunway TaihuLight, captured the number one spot on the latest TOP500 list of supercomputers released on Monday morning at the ISC High Performance conference (ISC) being held in Frankfurt, Germany.  With a Linpack mark of 93 petaflops, the system outperforms the former TOP500 champ, Tianhe-2, by a factor of three. The machine is powered by a new ShenWei processor and custom interconnect, both of which were developed locally, ending any remaining speculation that China would have to rely on Western technology to compete effectively in the upper echelons of supercomputing.”

Remarkably, the Sunway TaihuLight’s significant performance increase is delivered with lower power consumption than Tihane-2: 15,371 kW for TihauLight vs. 17,808 kW for Tihane-2.

You can read Michael Feldman’s complete article at the following link:

https://www.top500.org/news/china-tops-supercomputer-rankings-with-new-93-petaflop-machine/

You also can read the press release for the new TOP500 listing at the following link:

https://www.top500.org/news/new-chinese-supercomputer-named-worlds-fastest-system-on-latest-top500-list/

You’ll find the list of the top 10 supercomputers at the following link:

https://www.top500.org/lists/2016/06/

From here, you can navigate to the complete listing of all 500 supercomputers by going to the grey box titled RELEASE and selecting The List.

U.S supercomputers Titan and Sequoia are ranked 3rd and 4th, respectively, each with about 17% of the RMAX rating of the Sunway TaihuLight and half the power consumption. In comparison, the Sunway TaihuLight is significantly more power efficient than Titan and Sequoia.

15 July 2016 Update: National Science Foundation (NSF) examines the future directions for NSF advanced computing infrastructure

The NSF recently published the new report entitled, “Future Directions for NSF Advanced Computing Infrastructure to Support U.S. Science and Engineering in 2017-2020.”

NSF adv computing infrastructure report cover   Source: NAP

As described by the authors, this report “offers recommendations aimed at achieving four broad goals: (1) position the U.S. for continued leadership in science and engineering, (2) ensure that resources meet community needs, (3) aid the scientific community in keeping up with the revolution in computing, and (4) sustain the infrastructure for advanced computing.”

The report addresses the TOP500 listing, pointing to several known limitations, and concludes that:

“Nevertheless, the list is an excellent source of historical data, and taken in the aggregate gives insights into investments in advanced computing internationally.”

The NSF report further notes the decline in U.S. ranking in the TOP500 list (see pp. 59 – 60):

“The United States continues to dominate the list, with 45 percent of the aggregate performance across all machines on the July 2015 list, but it has dropped substantially from a peak of over 65 percent in 2008. NSF has had systems either high on the list (e.g., Kraken, Stampede) or comparable to the top systems (i.e., Blue Waters), reflecting the importance of computing at this level to NSF-supported science. Although there are fluctuations across other countries, the loss in performance share across this period is mostly explained by the growth in Asia, with China’s share growing from 1 percent to nearly 14 percent today and Japan growing from 3 to 9 percent.”

The report puts TOP500 rankings in perspective as it addresses future national scale advanced computing needs and operational models for delivering advanced computing services.

If you have a MyNAP account, you can download this report for free from National Academies Press (NAP) at the following link:

http://www.nap.edu/catalog/21886/future-directions-for-nsf-advanced-computing-infrastructure-to-support-us-science-and-engineering-in-2017-2020

NSF and LIGO Team Announce First Detection of Gravitational Waves

Peter Lobner

Today, 11 February 2016, the National Science Foundation (NSF) and the Laser Interferometer Gravitational-Wave Observatory (LIGO) project team announced that the first detection of gravitational waves occurred on 14 September 2015. You can view a video of this announcement at the following link:

https://www.youtube.com/watch?v=_582rU6neLc

The first paper on this milestone event, “Observation of Gravitational Waves From a Binary Black Hole Merger,” is reported in Physical Review Letters, at the following link:

http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102

The recorded signals from the two LIGO sites, Livingston, LA and Hanford, WA, are shown below, with the Hanford data time shifted to account for the slightly later arrival time of the gravitational wave signal at that detector location. The magnitude of the gravitational wave signal was characterized as being just below the detection threshold of LIGO before installation of the new advanced detectors, which improve LIGO sensitivity by a factor of 3 to 10.

LIGO signals

Source: NSF/LIGO

This milestone occurred during the engineering testing phase of the advanced LIGO detectors, before the start of their first official “observing run” on 18 September 2015.

Analysis and simulations conducted on the data indicate that the observed gravitational wave signals were generated when two orbiting black holes coalesced into a single black hole of smaller total mass and ejected about three solar masses of energy as gravitational waves.

In the Physical Review Letters paper, the authors provide the following diagram, which gives a physical interpretation of the observed gravitational wave signals.

Binary black holes merge

Note the very short timescale of this extraordinarily dynamic process. The recorded gravitational wave signals yielded an audible “chirp” when the two black holes merged.

With only two LIGO detectors, the source of the observed gravitational waves could not be localized, but the LIGO team reported that the source was in the southern sky, most likely in the vicinity of the Magellanic Clouds.

Localization of black hole merger Source: NSF/LIGO

The ability to localize gravitational wave signals will improve when additional gravitational wave detectors become operational later in this decade.

For more information on the current status of LIGO and other new-generation gravitational wave detectors, see my 16 December 2015 post: “100th Anniversary of Einstein’s Theory of General Relativity and the Advent of a New Generation of Gravity Wave Detectors.”

Update: 3 October 2017

 Congratulations to Rainer Weiss, Barry C. Barish, and Kip S. Thorne, all members of the LIGO / VIRGO Collaboration, for their award of the 2017 Nobel Prize in Physics for the first direct observation of gravitational waves. You can read the press release from the Royal Swedish Academy of Sciences here:

https://www.nobelprize.org/nobel_prizes/physics/laureates/2017/press.html

You also can read the scientific background on this award on the Royal Swedish Academy of Sciences website at the following link:

https://www.nobelprize.org/nobel_prizes/physics/laureates/2017/advanced-physicsprize2017.pdf

Just What are Those U.S. Scientists Doing in the Antarctic and the Southern Ocean?

Peter Lobner

The National Academies Press (NAP) recently published the report, “A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research”, which you can download for free at the following link if you have established a MyNAP account:

http://www.nap.edu/catalog/21741/a-strategic-vision-for-nsf-investments-in-antarctic-and-southern-ocean-research

Print Source: NAP

NSF states that research on the Southern Ocean and the Antarctic ice sheets is becoming increasingly urgent not only for understanding the future of the region but also its interconnections with and impacts on many other parts of the globe. The research priorities for the next decade, as recommended by the Committee on the Development of a Strategic Vision for the U.S. Antarctic Program; Polar Research Board; Division on Earth and Life Studies; National Academies of Sciences, Engineering, and Medicine, are summarized below:

  • Core Program: Investigator-driven basic research across a broad range of disciplines
    • NSF gives the following rationale: “…it is impossible to predict where the next major breakthroughs or advances will happen. Thus to ensure that the nation is well positioned to take advantage of such breakthroughs, it is important to be engaged in all core areas of scientific research.”
      • NSF notes, “…discoveries are often made by single or small groups of PIs thinking outside the box, or with a crazy new idea, or even just making the first observations from a new place.”
    • Examples of basic research that have led to important findings include:
      • Ross Sea food chain is affected by a high abundance of predator species (whales, penguins and toothfish) all competing for the same limited resource: krill. Decline or recovery of one predator population can be seen in an inverse effect on the other predator populations.  This food chain response is not seen in other areas of the Antarctic ice shelf where predator populations are lower, allowing a larger krill population that adequately supports all predators.
      • Basic research into “curious” very-low frequency (VLF) radio emissions produced by lightning discharges led to a larger program (with a 21.2-km-long VLF antenna) and ultimately to a better understanding of the behavior of plasma in the magnetosphere.
  • Strategic, Large Research Initiatives –  selection criteria:
    • Primary filter: compelling science – research that has the potential for important, transformative steps forward in understanding and discovery
    • Subsequent filters: potential for societal impact; time-sensitive in nature; readiness / feasibility; and key area for U.S. and NSF leadership.
    • Additional factors: partnership potential; impact on program balance; potential to help bridge existing disciplinary divides
  • Strategic, Large Research Initiative – recommendations::
    • Priority I: The Changing Antarctic Ice Sheets Initiative to determine how fast and by how much will sea level rise?
      • A multidisciplinary initiative to understand why the Antarctic ice sheets is changing now and how they will change in the future.
      • Will use multiple records of past ice sheet change to understand rates and processes.
    • Priority II: How do Antarctic biota evolve and adapt to the changing environment?
      • Decoding the genomic (DNA) and transcriptomic (messenger RNA molecules) bases of biological adaptation and response across Antarctic organisms and ecosystems.
    • Priority III: How did the universe begin and what are the underlying physical laws that govern its evolution and ultimate fate?
      • A next-generation cosmic microwave background (CBM) program that builds on the current successful CMB program using telescopes at the South Pole and the high Atacama Plateau in Chile and possibly will add a new site in the Northern Hemisphere to allow observations of the full sky

You will find detailed descriptions of the Priority I to III strategic programs in the Strategic Vision report.