Where’s my time machine?

Episode Summary

Executive Summary: This CrowdScience episode examines which sci-fi technologies are scientifically plausible versus still impossible. Physicist Andrew Ponson and transport expert Jack Stewart explain that time travel to the future is physically real via relativity, wormholes are speculative but could in theory link space and time, and flying cars are emerging as practical electric air taxis. The show also covers lightsabers, exoplanet sensors, artificial gravity, tricorders, needle-free injections, and planetary deflector shields.

Main Topics: Time travel and relativity (Priority: 5/5): Andrew explains that forward time travel is already happening at one second per second, and that moving near light speed would let travelers age more slowly than people on Earth. Backward time travel remains far more speculative. Teleportation and wormholes (Priority: 5/5): The discussion contrasts Star Trek-style transporters with quantum teleportation and wormholes. Quantum teleportation can transfer a particle’s state, but not a human body; wormholes are the best theoretical candidate for moving matter through space and possibly time. Flying cars / air taxis (Priority: 4/5): Jack Stewart argues that electric flying taxis are becoming realistic thanks to batteries, autonomy, advanced materials, and ride-hailing platforms. They may operate as short-hop urban air services rather than private garage-stored cars. Lightsabers and plasma weapons (Priority: 4/5): Dr. Kerry Brenner explains that lasers do not behave like Star Wars lightsabers because their beams are invisible sideways and do not form a blade. A plasma blade is more plausible in principle, but would need extreme heat, magnetic confinement, gas supply, and a very large power source. Detecting life on exoplanets (Priority: 4/5): Andrew describes how astronomers detect planets by dimming of stars and infer habitability from atmospheric spectra. Oxygen and methane are especially important possible biosignatures, and this capability is already in use today. Artificial gravity and space habitats (Priority: 3/5): Artificial gravity is presented as feasible through rotating habitats, like the wheel in 2001: A Space Odyssey, which creates gravity-like force via centrifugal effects. This is practical engineering rather than magical gravity generation. Medical and protective sci-fi tech (Priority: 3/5): Tricorders are approximated by smartphones plus sensors, needle-less injections are being developed with high-pressure liquid jets, and planetary deflector shields are closest to Earth’s magnetic field or a proposed artificial field for Mars.

Key Arguments: Forward time travel is scientifically real because relativity allows time to pass at different rates depending on speed and gravity. Backward time travel is much harder than forward time travel and has no practical technology behind it yet. Wormholes are the most plausible route to space-time shortcuts, but they require exotic energy and may not exist. Quantum teleportation transfers quantum state, not a whole person, so it is not a Star Trek transporter. Flying cars are becoming more realistic as electric vertical takeoff and landing vehicles integrated into urban transport networks. A true laser-based lightsaber is not plausible because laser beams do not form visible, solid blades; plasma confinement is a better but still difficult approach. Astronomers already infer atmospheres and potential life on exoplanets by spectroscopy, especially looking for oxygen and methane. Rotating space stations can simulate gravity well enough for human living, even if they are not true gravitational fields. Modern smartphones and add-on sensors are functionally close to a tricorder in many practical uses. Earth’s magnetic field already functions as a natural deflector shield, and similar protection for Mars has at least theoretical NASA concepts.

Data Points: Time travel rate: 1 second per second - Andrew states that everyone is already traveling forward in time at this rate. Speed threshold: Near the speed of light - Andrew says significant time dilation would require traveling extremely fast, near light speed. Flying car target year: 2023 - Jack cites Uber’s plan for operational networks in Los Angeles and Dallas by 2023. Passenger capacity: 5–6 people - Jack compares proposed flying taxis to scaled-up quadcopter drones carrying several passengers. Laser/plasma temperature: A couple of thousand degrees at least - Kerry says a lightsaber-like plasma blade would need to be extremely hot to cut through objects. Plasma jet speed: 200 meters per second - MIT’s needle-free injector uses a high-pressure liquid stream exiting the nozzle at this speed. Injector speed comparison: Mach 0.7 - The needle-free injection stream is compared to the cruising speed of a commercial airliner. Prize money: $10 million - Jack mentions the Tricorder X Prize offered this amount for a handheld medical scanner. Year: 2011 - The Tricorder X Prize was held in this year.

Pivotal Quotes: "We are all time travellers already." — Andrew Ponson: Used to explain that moving forward in time is a constant physical process, with relativity making different rates possible. "I think wormholes are probably more likely to be realisable than teleporters in that sense." — Andrew Ponson: His conclusion comparing theoretical wormholes with human-scale transporter technology. "I would replace all cars with them in a heartbeat." — Jack Stewart: Jack’s endorsement of flying taxis as a way to reduce urban traffic, noise, and pollution on roads.

Implications: Many sci-fi ideas are closer to reality than they seem, but usually in modified, less dramatic forms: air taxis instead of cars, sensors instead of tricorders, and plasma or magnetic engineering instead of magic beams. The biggest gap remains human teleportation and backward time travel.