Most physicists operate under the assumption that there is a world out there that is entirely independent of us, an objective reality in which more-or-less well-defined things behave according to immutable physical laws. Yet over the past century, ever since the development of quantum theory, there have been discombobulating questions about the role of observers – not least ourselves – in the makings of reality.

These questions are often brushed under the carpet, but Daniele Oriti, a theorist at the Complutense University of Madrid, prefers to confront them. Arguably, he has been pushed to do so by his work on one of the foremost challenges in modern physics: creating a quantum theory of gravity. The difficulty here is reconciling the inherently smooth picture of space-time in general relativity with quantum theory, which is written in contradictory mathematical language. Getting the two to play nicely together has forced Oriti to think deeply about the subtleties of physical laws – not least the fact that space-time is a shaky foundation on which to build them. His verdict? That physical laws can’t exist independently of us, as something that we can all agree on, but instead reside within us somehow.

Oriti spoke to New Scientist about how he came to such a startling conclusion, why physicists need to be more aware of the complex relations between the world, scientific models and observers, and how appreciating the true nature of physical laws might yield fresh breakthroughs.

Thomas Lewton: What do people get wrong about the nature of reality?

Daniele Oriti: At the risk of…

Dodging stormy weather ahead of Hurricane Milton, SpaceX launched the European Space Agency’s $398 million Hera probe Monday on a follow-up flight to find out precisely how a moonlet orbiting a small asteroid was affected by the high-speed impact of NASA’s DART probe in 2022.

The launching was in doubt until the last moment, with thick clouds and rain across Florida’s Space Coast, fueled by moisture pulled in by the intensifying hurricane to the west.

But as the launch time approached, conditions improved enough to satisfy launch safety rules and NASA managers cleared the rocket for takeoff. Right on time, at 10:52 a.m. EDT, the Falcon 9’s first stage engines ignited with a burst of flame and the booster climbed smoothly away from the Cape Canaveral Space Force Station.

Liftoff came in the nick of time for several hundred European Space Agency managers, scientists, engineers and journalists who flew to Florida to watch the launch.

Hurricane Milton is expected to bring extreme winds and torrential rain to Florida’s Space Coast by Wednesday, a forecast that prompted NASA to stand down on plans to launch the agency’s $5.2 billion Europa mission to Jupiter and its ice-covered moon Europa on Thursday.

Instead, NASA announced late Sunday the rocket and it costly payload will remain in a SpaceX hangar at the base of launch pad 39A at the Kennedy Space Center until Milton passes by and safety personnel have a chance to inspect spaceport facilities for signs of damage.

The weather also has thrown a wrench into NASA’s plans to bring three NASA astronauts and a Russian cosmonaut back to Earth after a 217-day stay aboard the International Space Station.

Crew 8 commander Matthew Dominick, Mike Barratt, Jeanette Epps and cosmonaut Alexander Grebenkin had planned to undock Monday.

But NASA announced Sunday their departure would be delayed to at least Thursday because of the expected bad weather. Crew Dragon ferry ships require calm winds and seas in the Gulf of Mexico or the Atlantic Ocean to permit a safe splashdown.

Mission to an asteroid and its moon

In the meantime, despite an initially grim forecast, SpaceX was able to take advantage of a break in the weather to kick off Hera’s two-year voyage to the asteroid Didymos and its small moon Dimorphos.

The DART impact altered the 11-hour 55-minute orbit of the 495-foot-wide Dimorphos, shaving 31 minutes off the time needed to complete one trip around the parent asteroid Didymos. The test confirmed the feasibility of someday nudging a threatening asteroid off course before a possibly devastating Earth impact.

But a successful deflection would depend on a variety of factors, including when the threat was detected — the farther out, the better — and the asteroid’s composition.

ESA’s Hera probe will orbit the Didymos system and study both asteroids in detail with 11 high-tech cameras and other instruments, deploying two small “cubesat” satellites to study the interior structure of Dimorphos, assess the DART impact crater, the moon’s internal structure and composition.

The goal of the Asteroid Impact and Deflection Assessment, or AIDA, is to better understand the techniques that might be needed to prevent an Earth impact.

“The good news is no dinosaur killer is on its way to Earth during the next 100 years,” said 
Richard Moissl, director of ESA’s Planetary Defense Office. “We are safe from that scenario, but there are smaller ones, especially in this dangerous size, 50 meters and upwards, where it really threatens human life on the ground.”

The first step in planetary defense is detection, he said, followed by detailed observations to pin down the asteroid’s orbit and determine whether a collision with Earth is a possibility.

“For small objects, civil protection is the way to go,” he said. “But 50 meters (160 feet across) and larger, you really want this thing not to hit Earth, not to threaten population centers. And then step three comes into play, deflection.

“But again, it’s always good to know what you’re up against. And this is where Hera and DART come into play.”

Unlike most Falcon 9 flights, there were no plans to recover the rocket’s first stage. To give Hera the velocity need to break free of Earth gravity, the Falcon 9’s two stages were programmed to use up all of their propellants, leaving none in reserve for a powered first stage landing.

The flight plan called for two firings of the upper stage engine before Hera’s release to fly on its own one hour and 16 minutes after liftoff.

To reach Didymos and Dimorphos, Hera will have to execute a deep space thruster firing in November to set up a gravity-assist flyby of Mars in March, sailing within about 3,700 miles of the red planet. Along the way, the spacecraft will pass within 620 miles of the small martian moon Deimos.

“By swinging through the gravitational field of Mars in its direction of movement, the spacecraft gains added velocity for its onward journey,” Michael Kueppers, ESA’s project scientist, said on the agency’s website.

“This close encounter is not part of Hera’s core mission, but we will have several of our science instruments activated anyway. It gives us another chance to calibrate our instruments and potentially to make some scientific discoveries.”

After another deep space maneuver in February 2026, Hera will finally be on course to slip into orbit around Didymos the following October. The mission is expected to last about six months.

A spacecraft is due to launch from Florida destined for an asteroid that US space agency Nasa knocked off course in 2022.

It is part of an international mission to see if we can stop dangerous asteroids hitting Earth.

The Hera craft will look at what happened to a space rock called Dimorphos when Nasa intentionally collided with it.

If all goes to plan, the spacecraft will reach Dimorphos in December 2026.

The Hera mission, which is run by the European Space Agency, is a follow-on from Nasa’s Double Asteroid Redirection Test (DART) project.

Dimorphos is a small moon 160m-wide that orbits an asteroid close to Earth called Didymos in something called a binary asteroid system.

In 2022 Nasa said it successfully changed Dimorphos’s course by crashing a probe into it. It altered the rock’s path by a few metres, according to Nasa’s scientists.

The asteroid was not on course to hit Earth, but it was a test to see whether space agencies could do it when there is genuine risk.

Now the Hera craft will look at the size and depth of the impact crater created on Dimorphos.

Two cube-shaped probes will also study the make-up of the asteroid and its mass.

“We need to understand what are the physical properties of these asteroids? What are they made of? Are they blocks of rock? Are they made of sand inside?” says Naomi Murdoch, a scientist involved with the European Space Agency mission.

That should help scientists understand the best way to attempt to intercept other asteroids, which can be many different sizes and shapes, in the future.

Scientists do not believe that we are currently at risk of a dinosaur-style extinction caused by an asteroid hitting Earth. An asteroid of that size could be easily spotted in space.

The size of asteroid that DART and Hera are targeting are about 100-200m wide and are very difficult to see from our planet.

From time to time they hit Earth. On 2013 a house-sized asteroid exploded in the sky above the town of Chelyabinsk in Russia. The shock wave blew out windows for over 200 square miles and damaged buildings. Over 1,600 people were injured in the blast.

Scientists hope to one day be able to identify asteroids like this and knock them off course.

“It’s not to avoid an extinction of the human race. It’s to create a system to minimize the damage as much as we can. The dinosaurs didn’t have a space program, but we do,” says Prof Murdoch.

But scientists warn that even though Nasa has proved it is possible to alter one asteroid’s course, it does not mean it can easily be done on all space rocks.

Intercepting an asteroid before it hits Earth also relies on being able to spot the incoming hazard in the first place.

Reuters

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