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1. Meet one of the humans who got us to Saturn
From Axios' Erin Ross: On Friday, the 20-year-long Cassini mission to Saturn will end. The spacecraft has flown through the planet's rings and discovered subterranean oceans on its moons. To protect the moons from the risk of being contaminated, Cassini will plunge into Saturn's atmosphere and disintegrate. Axios spoke with scientist and engineer Jo Pitesky, who has been with the project for 13 years, about Cassini's discoveries and what it means to be part of a decades-long space mission.
- The end: The spacecraft's final moments will be scientifically invaluable and the information gained will be "incredibly precious," says Pitesky. "There could be no better requiem for [Cassini]."
- The feeling: "You think you know what this stuff is going to look like, and then it just knocks your socks off. I don't think any of us will ever, ever, ever get tired of that."
- What's next: "I fully expect that there will be any number of science surprises coming from Cassini's dataset for decades."
Go deeper: Read more here.
2. China's superposition on building quantum networks
For decades, physicists have looked to use the behavior of particles of light to securely send information. The basic science underlying quantum cryptography has been determined over the past 40 years, but a slew of papers published this summer by physicist Jian-Wei Pan establishes China as the early leader in deploying the technology on a global scale.
Why it matters: Networks using quantum keys theoretically allow for very private communications and safe transactions — because if attacked, the key would be altered and the parties would know it wasn't secure. That would be valuable for financial transactions or voting that involves transmitting information between two points. But beyond a handful of field tests, there hasn't been a commitment to develop the technology at this scale until now.
Go deeper: Read the rest here.
P.S.: The extent to which quantum communications technologies can be commercialized remains to be seen. In China, the effort is government-funded. But for the rest of the world, a big question is whether there are industry customers for the technology. There currently are commercial applications and Battelle, for example, had been building a land-based network but told me in an email earlier this week: "We are no longer pursuing our QKD technology research at this time."
3. Axios stories to spark your brain
- Coming together: These autonomous robot units can form a larger robot and break apart again to adapt to their changing environment, writes Erica Pandey.
- Human evolution: A new study suggests the advent of farming didn't wipe out genetic diversity in people from Papua New Guinea. That's surprising because in other parts of the world, innovations and migration were prime forces in shaping human evolution.
- Tailored fibers: Chemists have figured out a way to give new properties to cotton without genetically engineering it.
- Farewell to Cassini: Erin Ross on the mission to Saturn's top findings.
4. What we're reading elsewhere
- The birth of zero: One of math's most important concepts first appeared in a text found in modern-day Pakistan that has now been dated to the 3rd or 4th century, writes The Guardian's Hannah Devlin. From mathematician Marcus Du Sautoy: "This is coming out of a culture that is quite happy to conceive of the void...That is exciting to recognise, that culture is important in making big mathematical breakthroughs."
- Cover story: IBM has used its quantum computer to simulate the behavior of every subatomic particle in a three-atom molecule. "In some ways, it's a small advance. But it's an important step on the path of ever-greater complexity in molecular simulation using quantum computers that will ultimately lead to commercially important breakthroughs," per MIT Technology Review. Think: new drug compounds and novel industrial materials.
- Cassini, another angle: A story of vengeance and dinosaurs, from Alex Parker.
4. Tried and true: Catching a quantum signal on the move
While reporting on China's space-based quantum communications efforts, I read about an ingenious experiment carried out by University of Waterloo researchers in 2015.
Quantum networks use quantum keys— basically a string of photons (particles of light) encoding a number key that, if intercepted, physically changes in a way that the parties in the exchange can identify as the message being compromised. Keys have been exchanged over fiber optic lines but only for up to a few hundred kilometers before the fiber absorbs the light signal. To transmit a key longer distances — from one continent to the next for example — physicists want to use satellites as relays.
What they did:
- Thomas Jennewein and his colleagues tested whether it is possible for a moving receiver to catch a quantum signal sent from Earth's surface.
- They sent single photons from a transmitter on the roof of a university building to a receiver mounted on a moving truck (standing in for a satellite) moving at the same angular speed as a satellite in low Earth orbit.
The result: The team was able to successfully exchange a quantum key between the transmitter and receiver and then extract the number encoded in it.
Why it mattered: It was the first reported demonstration of a quantum key being distributed from a stationary transmitter to a moving receiver. The satellite-like scenario was an important precursor to the experiments done with the Chinese satellite Micius that seek to extend the distance for performing quantum cryptography.
In enthusiastically describing his research to me this week, Filipe Natalio, a scientist at the Weizmann Institute of Science, mentioned cotton fiber is a single cell that elongates from as little as 10 micrometers (about a sixth the width of a human hair) to up to 3 cm. That extraordinary growth to become one of the largest single cells in plants happens in just 16 days.
Then, the cells fatten as they produce cellulose fibers. Eventually, pressure in the fruit (yes, cotton is a fruit) cracks it open and it is ready to be picked. Each cotton plant's ovary contains 20 ovules, each of which can grow up to 20,000 fibers.
Why it matters: These biological processes determine the length and strength of the fibers — two of the most important properties when it comes to cotton's value.