NASA captures unprecedented images of supersonic shockwaves

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This handout colorized composite image released by NASA on February 7, 2019 shows two T-38 aircrafts flying in formation at supersonic speeds producing shockwaves that are typically heard on the ground as a sonic boom. (AFP/NASA/HO)
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This handout colorized composite image released by NASA on February 7, 2019 shows two T-38 aircrafts flying in formation at supersonic speeds producing shockwaves that are typically heard on the ground as a sonic boom. (AFP/NASA/HO)
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This handout image released by NASA on February 7, 2019 shows a photo called a “knife-edge” shot of supersonic shock waves created by a single T-38. (AFP/NASA)
Updated 08 March 2019

NASA captures unprecedented images of supersonic shockwaves

  • The rendezvous at an altitude of around 30,000 feet yielded mesmerizing images of the shockwaves emanating from both planes
  • Sonic booms can be a major nuisance, capable of not just startling people on the ground but also causing damage

WASHINGTON: NASA has captured unprecedented photos of the interaction of shockwaves from two supersonic aircraft, part of its research into developing planes that can fly faster than sound without thunderous “sonic booms.”
When an aircraft crosses that threshold — around 1,225 kilometers (760 miles) per hour at sea level — it produces waves from the pressure it puts on the air around it, which merge to cause the ear-splitting sound.
In an intricate maneuver by “rock star” pilots at NASA’s Armstrong Flight Research Center in California, two supersonic T-38 jets flew just 30 feet (nine meters) apart below another plane waiting to photograph them with an advanced, high-speed camera, the agency said.
The rendezvous — at an altitude of around 30,000 feet — yielded mesmerizing images of the shockwaves emanating from both planes.
With one jet flying just behind the other, “the shocks are going to be shaped differently,” said Neal Smith of AerospaceComputing Inc, an engineering firm that works with NASA, in a post on the agency’s website.
“This data is really going to help us advance our understanding of how these shocks interact.”
Sonic booms can be a major nuisance, capable of not just startling people on the ground but also causing damage — like shattered windows — and this has led to strong restrictions on supersonic flight over land in jurisdictions like the United States.
The ability to capture such detailed images of shockwaves will be “crucial” to NASA’s development of the X-59, the agency said, an experimental supersonic plane it hopes will be able to break the sound barrier with just a rumble instead of a sonic boom.
A breakthrough like that could lead to the loosening of flight restrictions and the return of commercial supersonic planes for the first time since Concorde was retired in 2003.
Some countries and cities banned the Franco-British airliner from their airspace because of its sonic booms.


Tulips from Amsterdam? A blooming scam, says new probe

This file photo taken on March 6, 2003 shows bulbs at the flower market in Amsterdam. (AFP)
Updated 16 October 2019

Tulips from Amsterdam? A blooming scam, says new probe

  • Tulip bulbs should only be sold between August to December and planted before the start of the (northern hemisphere) winter, in order for the flowers to bloom in spring

THE HAGUE: Tourists are being ripped off at Amsterdam’s famous flower market, with just one percent of all bulbs sold at the floating bazaar ever producing a blossom, investigators said Tuesday.
A probe commissioned by the Dutch capital’s municipality and tulip growers also found that often only one flower resembled the pictures on the packaging like color, and that there were fewer bulbs than advertised.
“The probe showed that there is chronic deception of consumers,” at the sale of tulip bulbs at the flower market, the Royal General Bulb Growers’ Association (KAVB) said.
“Millions of tourists and day-trippers are being duped,” KAVB chairman Rene le Clercq said in a statement.
Amsterdam and the KAVB have now referred the matter to the Dutch consumer watchdog.
The Amsterdam flower market is one of the city’s most famous landmarks and dates from around 1862, when flower sellers sailed their barges up the Amstel River and moored them in the “Singel” to sell their goods.
Its fame inspired the popular song “Tulips from Amsterdam,” best known for a 1958 version by British entertainer Max Bygraves.
Today the market comprises of a number of fixed barges with little greenhouses on top. Vendors not only sell tulip bulbs but also narcissus, snowdrops, carnations, violets, peonies and orchids.
But of 1,363 bulbs bought from the Singel and then planted, just 14 actually bloomed, the investigation said.
Investigators found a similar problem along the so-called “flower bulb boulevard” in Lisse, a bulb-field town south of Amsterdam where the famous Keukenhof gardens are also situated.
Since first imported from the Ottoman Empire 400 years ago, tulips “have become our national symbol and the bulb industry a main player in the Dutch economy,” said Le Clercq.
But the “deception about the tulip bulbs is a problem that has been existing for the past 20 years,” he added.

The victims are often tourists, KAVB director Andre Hoogendijk said.
“A tourist who buys a bad bulb is not likely to come back,” he told Amsterdam’s local AT5 news channel.
Vendors at the market told AT5 that complaints were known.
“There are indeed stalls here that sell rubbish. That is to everyone’s disadvantage, because it portrays the whole flower market in a bad light,” one unidentified vendor said.
But a spokesperson for the City of Amsterdam said that all vendors were being investigated “and that the results are shocking.”
“So to say that it is only a few stalls is not true,” the spokesperson told AFP in an email.
The probe took place earlier in the year during springtime, the spokesperson said.
“The issue is that you shouldn’t even sell tulip bulbs during the spring. No decent florist shop in Holland does that.”
Tulip bulbs should only be sold between August to December and planted before the start of the (northern hemisphere) winter, in order for the flowers to bloom in spring.