Artificial moons '8 times brighter than the real moon' to light up city streets




China wants to build three artificial moons “eight times brighter than the real moon” to light up city streets.
The moons will have an area anywhere between 10 to 80km wide.
It’s estimated the moons would save the city about 1.2 billion yuan ($240 million) in electricity costs every year.
It hopes to have the project completed in four years.

However some experts say it “potentially creates significant new environmental problems”.
Within four years, Chinese scientists plan to have three artificial moons “eight times brighter than the real moon” shining down on their city streets.
Can it be done? The project has already been developed by the Chengdu Aerospace Science and Technology Microelectronics System Research Institute Corporation.
China’s fake moons, according to state media People’s Daily, will light up the streets of Chengdua at night with “a dusk-like glow” across an area anywhere between 10 to 80km wide — bright enough to replace streetlights.

Wu Chunfeng, chairman of Chengdu Aerospace Science and Technology Microelectronics System Research Institute Corporation, said if the moons could light up 50km of Chengdu at night, it would save the city about 1.2 billion yuan ($240 million) in electricity costs every year.
The three moons would be made from reflective material and operate alternately from their orbits 500km above the Earth, Wu said. By 2022, “the three huge mirrors will divide the 360-degree orbital plane, realizing illuminating an area for 24 hours continuously”.
The real question is should it be done?

Astronomers and the anti-space junk community would no doubt be horrified. They’re still reeling at plans by artist Trevor Paglen to send a 33-metre reflective obelisk into orbit via a
SpaceX rocket later this year, claiming it’s a danger and “the space equivalent of someone putting a neon advertising billboard right outside your bedroom window”.
But while the “Orbital Reflector” will rival the Big Dipper for brightness, it will burn up within a couple of months.

John Barentine, Director of Public Policy at the International Dark-Sky Association, told Forbes the “solution” to Chengdu’s problems “potentially creates significant new environmental problems”.
“The Chengdu ‘artificial moon’ would have the effect of significantly increasing the nighttime brightness of an already light-polluted city, creating problems for both Chengdu’s residents, who are unable to screen out the unwanted light, as well as for the urban wildlife population that can’t simply go inside and close the shutters,” he said.
And if it sounds implausible, reflecting the Sun’s rays back to Earth at night has actually been done before.

In 1993, Russia successfully coaxed a beam 5km wide from a 20-metre solar mirror called Znamya 2 that was roughly as bright as a full moon. However, a piece of the reflective umbrella caught on an antenna as it was unfurling, and the satellite was deorbited after a couple of hours.








Laser in space could help spot submarines

 Will China’s new laser satellite become the ‘Death Star’ for submarines?
The team has come up with an innovative approach that has not been tried before. The device is designed to generate high-power laser beam pulses in different colours, or frequencies, that allow sensitive receivers to pick up more information from various depths. 
The main target for the satellite was the thermocline – a thin layer of water where the temperature changes abruptly. The thermocline is known to be important for submarine captains because it can reflect active sonar and other acoustic signals. That means a vessel could potentially avoid detection in the thermocline, but not by a laser beam.

New spy satellite 'Project Guanlan' could use lasers to spot submarines up to 1,600ft (500m) below the ocean's surface.

These lasers will be so powerful they will make the upper layer of the sea 'more or less transparent', according to scientists involved in the project. 
Researchers claim these artificial laser beams could be one billion times brighter than the sun.
However, some experts say this type of deep-sea surveillance is 'mission impossible' as lasers are fundamentally unable to penetrate that deep.

China's new Project Guanlan satellite uses lasers to spot objects deep under water. In theory when a laser hits an object - such as a submarine - pulses bounce back and are picked up by sensors, which can determine the size, shape and location of the object
China's new Project Guanlan satellite uses lasers to spot objects deep under water. In theory when a laser hits an object - such as a submarine - pulses bounce back and are picked up by sensors, which can determine the size, shape and location of the object
 
Project Guanlan, meaning “watching the big waves”, was officially launched in May at the Pilot National Laboratory for Marine Science and Technology in Qingdao, Shandong.
 Its components are being developed by more than 20 universities across the country.
For more than half a century naval researchers have been attempting to create a laser using Lidar (a portmanteau of 'light and radar.').
In theory when a laser hits an object - such as a submarine - pulses will bounce back and be picked up by sensors, which will be able to determine its shape.


Scientists are working on a device they hope will be able to reveal the location of a target as far as 500 metres below the ocean surface.

Experiments carried out by the United States and former Soviet Union achieved maximum detection depths of less than 100 metres, according to openly available information.
That range has been extended in recent years by the US in research funded by Nasa and the Defence Advanced Research Projects Agency (DARPA). A device developed by DARPA, for example, was mounted on a spy plane and achieved reliable results at a depth of 200 metres, detecting targets as small as sea mines.

According to researchers, this high-powered laser beam is so powerful it would be able to scan an area as wide as 62 miles (100km) on land, or concentrate on one spot just 1km wide.

It will be used in conjunction with a microwave radar, also mounted on the satellite, to better identify targets.
Although the radar cannot penetrate water, it can measure the surface movement with extremely high accuracy – so when a moving submarine creates small disturbances on the surface, for example, the radar will tell the satellite where to throw the laser beam.

Lidar uses ultraviolet, visible, or near infrared light to image objects. 
It can be used with a wide range of targets, including non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds and even single molecules.

China's new spy satellite 'Project Guanlan' could use lasers to spot submarines up to 1,600ft (500m) below the ocean's surface. This high-powered laser beam will be so powerful it would be able to scan an area as wide as 62 miles (100km) on land (stock image) 
China's new spy satellite 'Project Guanlan' could use lasers to spot submarines up to 1,600ft (500m) below the ocean's surface. This high-powered laser beam will be so powerful it would be able to scan an area as wide as 62 miles (100km) on land (stock image) 

However, it is negatively affected by fog, murky water and marine life. 
It also works less well in water as light scatters when it hits the surface.
Researchers say the aim of the project is to strengthen Chinese surveillance.
Song Xiaoquan, who is involved in the project, said it will make the upper layers of the ocean 'more or less transparent'.
He said it 'will change almost everything'.
Dr Xuaiquan said he did not know when the satellite would be ready.

“Five hundred metres is ‘mission impossible’,” said a lidar scientist with the Shanghai Institute of Optics and Fine Mechanics at the Chinese Academy of Sciences, who is not involved in the project.
'They [project researchers] won't be able to break through the darkness guarded by Mother Nature – unless of course they are Tom Cruise, armed with some secret weapons,' one anonymous researcher from the Shanghai Institute of Optics and Fine Mechanics at the Chinese Academy of Sciences told SCMP.  

WHAT IS LIDAR TECHNOLOGY AND HOW DOES IT WORK?

Lidar is a remote sensing technology that measures distance by shooting a laser at a target and analysing the light that is reflected back.
The technology was developed in the early 1960s and uses laser imaging with radar technology that can calculate distances.
It was first used in meteorology to measure clouds by the National Center for Atmospheric Research.
The term lidar is a portmanteau of 'light and 'radar.'
Lidar uses ultraviolet, visible, or near infrared light to image objects and can be used with a wide range of targets, including non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds and even single molecules.
A narrow laser beam can be used to map physical features with very high resolution. 
This new technique allowed researchers to map outlines of what they describe as dozens of newly discovered Maya cities hidden under thick jungle foliage centuries after they were abandoned by their original inhabitants.
Aircraft with a LiDAR scanner produced three-dimensional maps of the surface by using light in the form of pulsed laser linked to a GPS system. 
The technology helped researchers discover sites much faster than using traditional archaeological methods.