The subject of time travel seems to have divided into three camps: the fictional yet realistic and hopeful version in the movies and television, the surrealistic ‘revelations’ by Tik Tok time travelers allegedly from the future, and the quantum version which only quantum physicists understand. Ronald Mallett would like to add a new one to the list – the use of a ring of rotating lasers to make a loop of time that would enable him to travel backwards in time to when he was ten years old and his father was still alive. This just might be the version that is worthy of a movie, supported by science and will put the Tik Tok ‘time travelers’ to shame.
“Everything for me began with my father, for me, literally, the sun rose and set on him. He died suddenly of a massive heart attack.”
Ronald Mallett is now 77 years old and an emeritus professor of physics at the University of Connecticut. In The Guardian, he gives a loving and detailed biography of his father, Boyd Mallet – a hardworking World War II veteran with an interest in electronics who died suddenly of a heart attack. Mallett confesses that times were hard for a fatherless African American 10-year-old, and he dealt with the stress by reading books. One of his favorites was “The Time Machine” by H.G. Wells – a book that inspired him to build a model time machine out of bicycle and radio parts like the illustration the cover. The book also inspired Mallett to read about Albert Einstein. After serving in the military, he enrolled at Penn State and became one of the first African Americans to receive a PhD in physics. If this were a movie script, Mallett would have taught physics by day and worked on a time machine in his garage at night. That’s almost what happened.
“Scientific people know very well that time is just a kind of space and we can move forward and backwards in time, just as we can in space.”
Mallett was definitely a scientific person, just the kind H.G. Wells described in the opening paragraph of “The Time Machine.” But the astrophysicist was also a realist who knew that time travel was unproven, controversial and contrary to certain laws … and that a serious interest in it could hamper his career advancement. So he did his research after hours and in secret. That changed in the mid-90s when he had his own close encounter with a heart condition and needed angioplasty surgery and a long non-working recovery. This gave him the ‘time’ to ‘travel’ back to his lifelong interest, and especially to the scientific studies he hadn’t had time to read before. That is when Mallett found missing piece he had been searching for.
“It turns out that rotating black holes can create a gravitational field that could lead to loops of time being created that can allow you to go to the past.”
As a fan of Einstein, Mallett was familiar with rotating or spinning black holes – two of the four kinds of black holes which solve the Einstein field equations relating to the geometry of spacetime to the distribution of matter within it are rotating black holes – the Kerr and Kerr–Newman black holes. These spinning black holes have two event horizons instead of one sucking in electromagnetic radiation. In the space between the inner and outer event horizons, the dragging of space-time occurs – a process known as frame dragging. Knowing we all have scrunched up puzzled faces at this point (go ahead, look in the mirror), Mallett is kind enough to give a simple example.
“Let’s say you have a cup of coffee in front of you right now. Start stirring the coffee with the spoon. It started swirling around, right? That’s what a rotating black hole does. (But) in Einstein’s theory, space and time relate to each other. That’s why it’s called space-time. So as the black hole is rotating, it’s actually going to cause a twisting of time.”
That sounds too simple to be true … and rotating black holes are pretty rare in the universe. That’s where the ‘ring of rotating lasers’ comes in. While it may sound like something from a Pink Floyd concert, this is based on a real device called a ring laser – actually, a pair of laser beams of the same polarization rotating in opposite directions in a closed loop. These ring lasers are in use on ships, planes, missiles and even cars as a gyroscope. Extremely large ones are used by astronomers for detecting gravitational waves. So, can ring lasers really help Professor Mallett travel back in time like Doc Brown in “Back to the Future”?
“Light can create gravity … and if gravity can affect time, then light itself can affect time.”
That makes sense … and not just to this writer but to scientists as well. They have just one problem with a ring laser time machine – the amount of energy needed for it to bend time, which would affect the size of the machine. Some researchers have estimated that the ring laser time machine would have to be the size of the known universe. When asked how big he thought it would be, Mallett told The Guardian he didn’t know. When asked how much energy it would need, Mallett said, “You’re talking about galactic types of energy in order to do that.” This is obviously bigger than a Pink Floyd laser light show. However, it is still possible. Mallett says he’s at the stage in ring laser time travel like the Wright brothers were in their lab – they knew their science was sound and their plane would get off the ground, but they had no idea how to use that same science to put a craft on the Moon. Mallett knows the science of ring lasers works – an intense, continuous rotating beam of light can affect time. He just doesn’t know how much light he’ll need to make a working time loop.
Ronald Mallett also knows one more thing that those Tik Tok time travelers don’t – a ring laser time loop will only allow travel back in time to the point when the time loop was created. That is not 1955, which means Mallett can’t go back to visit his father. He’s now hoping instead to lay the groundwork for a machine that will allow people of our future to come back to visit us – possibly returning with cures for diseases, or that Tik Tok time travel staple … warning of disasters.
It could work.Boyd Mallett and Doc Brown would no doubt be proud.