TORONTO —
It sounds impossibly far-fetched, but could a megastructure built around the sun be powerful enough to steer the entire solar system through the Milky Way?
One astrophysicist is the latest to demonstrate how it might be possible with two stellar engine designs based on the latest understanding of physics. One of the megastructures would be theoretically fast enough to move the solar system by 50 light-years in about a million years, providing enough time and distance to steer clear of a powerful explosion from a dying star, for example.
The solar system can be hypothetically moved this way, because everything in it is pulled by the sun’s gravity, keeping it all in constant orbit.
The proposed designs by Matthew Caplan, a nuclear astrophysicist at Illinois State University, was published in the December 2019 issue of the peer-reviewed journal Acta Astronautica.
One is an extremely thin parabolic solar “sail” or giant mirror much like the “Shkadov thruster“. It would be made from highly reflective material, thinner than a red blood cell, positioned over the sun’s poles, and would not orbit. Caplan noted that metal foils of 0.2 micrometre are commercially available. The position of the mirror is crucial in order to avoid impacting the Earth’s temperature, but it also limits the direction in which the solar system can be steered.
The solar radiation reflected onto the giant mirror creates thrust and would slowly push the sun. With this “passive” method, the solar system could move as much as 100 light-years over 230 million years, according to an animated explanatory video by the Kurzgesagt YouTube channel. This would not be fast or far enough to avoid the “kill radius” of a supernova, however, Caplan wrote in his paper.
The other design was for a faster, “active” thruster, dubbed the “Caplan thruster” by Kurzgesagt, which had originally asked him to make the designs for a video. The Caplan thruster would work much like a rocket, blasting out photon particles to propel itself forward. The thermonuclear-driven thrusters would require millions of tons of fuel per second and are a modified form of the “Bussard ramjet“, a conceptual interstellar spacecraft propelled by fusion energy.
Caplan’s design would collect matter from solar wind through a large electromagnetic field to create fusion. There are two jets, one directed toward the sun (to prevent a collision with the star) and one away from the sun that creates a net momentum, functioning like a tug boat. A Dyson sphere would be used to lift billions of tons of mass off the sun, providing a large amount of fuel to power the jets.
A Dyson sphere is an enormous structure, such as a shell or a ring, built around a star and uses its radiation to capture energy. The concept was the product of a thought experiment on how highly advanced civilizations might satisfy its ever growing energy demand.
The Caplan thruster design would move fast enough to avoid a supernova and could redirect the solar system in its galactic orbit in about 10 million years.
“A stellar engine produces a small net acceleration of the star, not large enough to disruptthe planetary system on short timescales, but sufficiently large to deflect the star and planetary system in its galactic orbit by many light-years given millions of years,” Caplan wrote in his paper. Caplan was a Canadian Institute for Theoretical Astrophysics National Fellow.
“A catastrophe such as a supernova could likely be predicted millions of years in advance, at a minimum, for an advanced civilization with detailed understanding of star formation and the supernova mechanism.”
Megastructures and stellar engines themselves are not exactly new. These hypothetical concepts have been around for many decades, and have also made numerous appearances in popular culture.
Captain Picard and his crew on Star Trek: The Next Generation encountered a Dyson sphere during an investigation into a Federation ship that had been missing for decades. It powers a weapons forge on Nidavellir, a dying neutron star in Avengers: Infinity War. In The Expanse novels and television series, a megastructure turns out to be an artificial wormhole built by an extinct alien civilisation.
“With the Caplan thruster, we could turn the entire solar system into our spaceship,” Kurzgesagt said in its video, adding stellar engines would be built by civilizations thinking in terms of eons, not decades.
Humanity could colonize other parts of the Milky Way, or escape the galaxy altogether, Kurzgesagt added. “A stellar engine could allow the far future descendants of humans to travel to other stars without ever having to venture into the terrifying dark abyss of interstellar space.”
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
