Hawking, who died in 2018, supported this ambitious research project to develop interstellar exploration technologies.
Theoretical physicist, astrophysicist and cosmologist Stephen Hawking he was quite a visionary, so much so that he even considered that the future of humanity was not on Earth. In this way, the also scientific popularizer urged humanity to begin the process of build permanent establishments on other planets.
“We are running out of space and the only spaces we can go to are other worlds,” Hawking said in 2017, during a lecture at the International Starmus Festival in Norway. “It’s time to explore other solar systems. Expanding may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth,” he added.
According to Hawking _ who died in March 2018 from amyotrophic lateral sclerosis he suffered from _, sooner rather than later humanity would be the victim of a catastrophe that would push the species to extinction.
What the astrophysicist was most concerned about were the so-called low-probability, high-impact events; for example, the collision of a large asteroid with the planet. But he also perceived other potential threats, such as the artificial intelligence, climate change, genetically modified viruses and possible nuclear war, to cite a few examples.
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In 2016 Hawking told the British network BBC: “Although the probability that the Earth will suffer a disaster soon is quite low, it accumulates over time and becomes almost a certainty for the next thousand or 10 thousand years.”
While he was convinced that humans would be inhabiting other parts of the cosmos by then, he also said, “We’re not going to establish self-sustaining colonies in space for at least the next 100 years, so we have to be very careful until then”.
Breakthrough Starshot
In line with his ideas, in 2016 Hawking supported an ambitious research project to develop interstellar exploration technologies called Breakthrough Starshot, which consists of a spacecraft propulsion system with one hundred million laser beams emitted from Earth to explore Alpha Centauri, our second closest star.
The Breakthrough Starshot project requires the design of an ultralight spacecraft, acting like a light sail, to travel at unprecedented speed over tens of trillions of kilometers to the star some four light-years away, reaching the destination. in 20 years.
The large scale and size of the interstellar distances between solar systems is difficult for most people to understand. Traveling from Earth to Alpha Centauri using today’s conventional spacecraft would take over 100 lifetimes.
In an article published in the Journal of the Optical Society of America B, the Australian National University (ANU) team, with financial support from Breakthrough Initiatives, describes their design concept for the laser propulsion system that will be used to launch the probes from Earth.
Lead author Dr Chathura Bandutunga said in a statement that the light to power the candle will come from the Earth’s surface: a giant laser array with millions of lasers that act in concert to illuminate the sail and propel it forward on its interstellar journey.
“To bridge the vast distances between Alpha Centauri and our own solar system, we need to think outside the box and forge a new way of interstellar space travel,” explained Bandutunga, from the Applied Metrology Laboratories at the ANU Center for Gravitational Astrophysics.
“Once en route, the sail will fly through the vacuum of space for 20 years before reaching their destination. During its flyby of Alpha Centauri, it will record images and scientific measurements that it will transmit back to Earth.”
The ANU team has experience in different areas of optics including astronomy, instrumentation of gravitational waves, fiber optic sensors and optical phased arrays.
The founding scientist who pioneered the ANU node of this project, Dr. Robert Ward, said that an important part of this great vision is the development of the laser array, in particular, the design of a system for all lasers to act as one.
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One hundred million laser beams guided by a satellite
“The Breakthrough Starshot program estimates that the total optical power required is about 100 GW, about 100 times the capacity of the largest battery in the world today,” said Ward, from the ANU Research School of Physics. “To achieve this, we estimate the number of lasers needed to be about 100 million.”
Researcher and colleague Dr Paul Sibley said that one of the main challenges we tackle is how to make measurements of the drift of each laser.
“We use a random digital signal to encode the measurements of each laser and encode each one separately in digital signal processing,” he said.
“This allows us to select just the measurements we need from a vast jumble of information. We can then break the problem into small arrays and join them into sections.”
To orchestrate the show, ANU’s design calls for a Beacon satellite, a guide laser placed in Earth orbit that acts as a conductor, linking the entire array of lasers together.
Professor Michael Ireland of the ANU Research School of Astronomy and Astrophysics said the design of the laser “engine” requires compensation for the atmosphere.
“Unless corrected, the atmosphere distorts the outgoing laser beam, causing it to stray from its intended destination,” he said.
“Our proposal uses a laser guide star. It’s about a small satellite with a laser that illuminates the array from Earth orbit. As the laser guide star passes through the atmosphere on the way back to Earth, it measures changes due to the atmosphere.
“We have developed the algorithm that allows us to use this information to pre-correct the light coming out of the array.”
Bandutunga said that, like eventual dinghy sailing, this research is at the beginning of a long journey. “While we are confident in our design, the proof is in the pudding,” he said.
“The next step is to start testing some of the basic building blocks in a controlled laboratory environment. This includes the concepts for combining small arrays to make larger arrays and the atmospheric correction algorithms.” (I)
Sources: Europa Press || BBC
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