Doctor Strange is portrayed by Benedict Cumberbatch in "Doctor Strange in the Multiverse of Madness." (Marvel Entertainment)
What is the multiverse? The idea that the universe we inhabit is just one of many parallel universes gets a superhero shout-out in “Doctor Strange in the Multiverse of Madness,” the latest movie based on Marvel comic-book characters.
And in the opinion of Brian Greene, a theoretical physicist at Columbia University, giving some screen time to the multiverse isn’t such a bad thing — even if the plot has some horror-movie twists.
“I think it’s really good if some of these ideas are brought out in a variety of different ways,” Greene says in the latest episode of the Fiction Science podcast, which focuses on the realm where science and technology intersect with fiction and popular culture.
Space shuttle Endeavour docks at the International Space Station while the Moon hurtles towards the Earth in the epic sci-fi film, MOONFALL. Image courtesy Lionsgate.
The master of disaster has struck again, and this time our Moon is the ominous villain.
In “Moonfall,” film director Roland Emmerich (Independence Day, The Day After Tomorrow, 2012) has created yet another sci-fi disaster film where the world faces obliteration from mysterious forces.
On March 4th, 2021, the Perseverance rover began driving from its landing site on Mars. During this drive, the rover covered 6.5 meters (21.3 feet) and conducted some basic maneuvers and instrument tests. In keeping with a NASA tradition where mission controllers give unofficial nicknames to various geological features, the team also consecrated the landing site by naming it after a famous science fiction author.
Henceforth, the site where Perseverance landed will be known as the “Octavia E. Butler Landing,” in honor of the groundbreaking science fiction author who passed away in 2006 (she was 59 years old). Butler is renowned for being the first African-American woman to win both the Hugo and Nebula Award and was the first science fiction author honored with a MacArthur Fellowship (in 1995).
The Enterprise using warp drive, as seen in Star Trek Beyond. Credit: Paramount Pictures
If you want a galaxy-spanning science fiction epic, you’re going to need faster than light travel. The alternative is taking decades or centuries to reach an alien star system, which isn’t nearly as much fun. So, you start with some wild scientific idea, add a bit of technobabble, and poof! Quam Celerrime ad Astra. Everything from wormholes to hyperspace has been used in sci-fi, but perhaps the best known FTL trope is warp drive.
The Full Moon at 10:30 p.m. last night (Aug. 30). Even at 25 altitude, it glowed a deep, dark orange due to heavy smoke from western forest fires. Credit: Bob King
Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that Earth hasn’t been visited by aliens because interstellar travel is not very practical!
In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?“
This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Since Fermi’s time, there have been several proposed resolutions to his question, which includes the Dark Forest Hypothesis, where extraterrestrial civilizations are deliberately avoiding contact.
The Cold Spot area resides in the constellation Eridanus in the southern galactic hemisphere. The insets show the environment of this anomalous patch of the sky as mapped by Szapudi’s team using PS1 and WISE data and as observed in the cosmic microwave background temperature data taken by the Planck satellite. The angular diameter of the vast supervoid aligned with the Cold Spot, which exceeds 30 degrees, is marked by the white circles. Credit: ESA Planck Collaboration/ Gerg? Kránicz
In the New Testament, the book of John opens with In the beginning was the Word. Whether a poetic musing of philosophy or a declaration of faith, it encapsulates an idea that has been around a long time. If the cosmos was made, either by advanced aliens or a divine creator, might this architect have buried a message within the universe? Some absolute proof of intentional design.
This dramatic infrared image shows the nearby star formation region Monoceros R2, located some 2700 light-years away in the constellation of Monoceros (the Unicorn). The picture was created from exposures in the near infrared bands Y, J and Ks taken by the VISTA survey telescope at ESO’s Paranal Observatory. Monoceros R2 is an association of massive hot young stars illuminating a beautiful collection of reflection nebulae, embedded in a large molecular cloud. This image is available as a mounted image in the ESOshop.
Are we alone in the universe?
It is one of the most profound questions posed in modern astronomy. But although our understanding of the cosmos has grown significantly, the question remains unanswered. We know that Earth-like planets are common, as are the building blocks necessary for terrestrial life, and yet we still haven’t found definitive evidence for life beyond Earth. Perhaps part of our problem is that we are mostly looking for life similar to our own. It is possible that alien life is so radically different from that of Earth it goes unnoticed.
A new study considers what life could be like for civilizations 1 trillion years from now, when every star in the Universe will expand beyond the cosmic horizon. Credit: ESO/S. Brunier
Welcome back to our Fermi Paradox series, where we take a look at possible resolutions to Enrico Fermi’s famous question, “Where Is Everybody?” Today, we examine the possibility that we can’t see them because they have us all inside a massive simulation!
In 1950, Italian-American physicist Enrico Fermi sat down to lunch with some of his colleagues at the Los Alamos National Laboratory, where he had worked five years prior as part of the Manhattan Project. According to various accounts, the conversation turned to aliens and the recent spate of UFOs. Into this, Fermi issued a statement that would go down in the annals of history: “Where is everybody?“
This became the basis of the Fermi Paradox, which refers to the disparity between high probability estimates for the existence of extraterrestrial intelligence (ETI) and the apparent lack of evidence. Seventy years later, we are still trying to answer that question, which has led to some interesting theories about why we haven’t. A particularly mind-bending suggestion comes in the form of the Planetarium Hypothesis!
Hello all. I hope our readers don’t mind that I’m taking a bit of a diversion here today to engage in a little shameless self-promotion. Basically, I wanted to talk about my recently-published novel – The Jovian Manifesto. This book is the sequel to The Cronian Incident, which was published last year (and was a little shamelessly promoted at the time).
However, I also wanted to take this opportunity to talk about hard science fiction and how writing for a science publication helped me grow as a writer. By definition, hard sci-fi refers to stories where scientific accuracy is emphasized. This essentially means that the technology in the story conforms to established science and/or what is believed to be feasible in the future.
So when I set out to write The Cronian Incident, I wanted it to be as realistic as possible, both in terms of technology and setting. Many of the ideas I came up with, and much of the material I drew from, was inspired from my work here at Universe Today. Since I joined the team in 2010 and became a regular member in 2014, I’ve had the chance to write about space-related news, as well as exciting research and scientific breakthroughs.
Now, don’t get me wrong, Science Fiction is awesome. Like almost everyone working in the field of space and astronomy, I was deeply influenced by science fiction. For me, it was Star Trek and Star Wars. I had a toy phaser that made this awesome really loud phaser sound, and I played with it non-stop until it disappeared one day. And I was sure I’d left it in the middle of my floor, like I did with all my toys, but I found it a few years later, hidden up in a closet that I couldn’t reach. And I always wondered how it got there.
Anyway, back to science fiction. For all of its inspiration, science fiction has put a few ideas into our brains which aren’t entirely helpful. You know, warp drives, artificial gravity, teleportation, and rockets that take off, fly to space, visit other planets orbiting stars, land again.
The Millennium Falcon, Firefly, and Enterprise Shuttles are all examples of single stage to orbit to orbit spacecraft, or SSTOs.
Consider the rockets that exist in reality, you know, the Atlases, Falcons and Deltas. They take off from a launch pad, fly for a bit until the fuel is used up in a stage of the rocket, then they jettison that stage and thrust with the next stage. The mighty Saturn V was so powerful that it had three stages, as it made it’s way to orbit.
Diagram of Saturn V Launch Vehicle. Credit: NASA/MSFC
As we discussed in a previous article, SpaceX is working to make the first stage, and maybe even the second stage reusable, which is a vast improvement over just letting everything burn up, but there are no rockets that actually fly to orbit and back in a single stage. In fact, using the technology we have today, it’s probably not a good idea.
Has anyone ever worked on a single stage to orbit? What technological advances will need to happen to make this work?
As I said earlier, a single stage to orbit rocket would be something like the Millennium Falcon. It carries fuel, and then uses that fuel to fly into orbit, and from world to world. Once it runs out of fuel, it gets filled up again, and then it’s off again, making the Kessel Run and avoiding Imperial Blockades.
This concept of a rocket matches our personal experience with every other vehicle we’ve ever been in. You drive your car around and refuel it, same with boats, airplanes and every other form of Earth-based transportation.
But flying into space requires the expenditure of energy that defies comprehension. Let me give you an example. A Falcon 9 rocket can lift about 22,800 kilograms into low-Earth orbit. That’s about the same as a fully loaded cement truck – which is a lot.
SpaceX Falcon 9 poised for Jan. 14, 2017, Return to Flight launch from Vandenberg Air Force Base in California carrying ten Iridium NEXT comsats to orbit. Credit: SpaceX
The entire fueled Falcon 9 weighs just over 540,000 kg, of which more than 510,000 kgs of it are fuel, with a little extra mass for the engines, fuel tanks, etc. Imagine if you drove a car that was essentially 95% fuel.
The problem is specific impulse; the maximum amount of thrust that a specific kind of engine and fuel type can achieve. I’m not going to go into all the details, but the most efficient chemical rockets we have, fueled by liquid hydrogen and oxygen, can just barely deliver enough thrust to get you to orbit. They have a maximum specific impulse of about 450 seconds.
Because the amount of fuel it takes to launch a rocket is so high, modern rockets use a staging system. Once a stage has emptied out all its fuel, it detaches and returns to Earth so that the second stage can keep going without having to drag along the extra weight of the empty fuel tanks.
After stage separation of the Falcon 9 rocket, flames are barely visible around nozzle as the second stage engine ignites and the first stage falls back to the Earth below. Credit: SpaceX
You might be surprised to know that many modern rockets are actually capable of reaching orbit with a single stage. The problem is that they wouldn’t be able to carry any significant payload.
At the end of the day, considering the chemical rockets we have today, the multi-staged profile is the most efficient and cost-effective strategy for carrying the most payload to space for the lowest cost possible.
Has anyone tried developing SSTOs in the past? Definitely. Probably the most widely publicized was NASA’s X-33/VentureStar program, developed by Lockheed Martin in the 1990s.
The proposed X-33 spacecraft. Credit: NASA
The purpose of the X-33 was to test out a range of new technologies for NASA, including composite fuel tanks, autonomous flight, and a new lifting body design.
In order to make this work, they developed a new kind of rocket engine called the “aerospike”. Unlike a regular rocket engine which provide a fixed amount of thrust, an aerospike could be throttled back like a jet engine, using less fuel at lower altitudes, where the atmosphere is thickest.
The test of twin Linear Aerospike XRS-2200 engines, originally built for the X-33 program, was performed on August 6, 2001 at NASA’s Sternis Space Center, Mississippi. The engines were fired for the planned 90 seconds and reached a planned maximum power of 85 percent. Credit: NASA’s Marshall Space Flight Center
Lockheed Martin was working on a 1/3rd scale prototype, but they struggled with many of the new technologies. In the end, their failure to be able to build a composite fuel tank that could contain the liquid oxygen and hydrogen forced them to abandon the project.
Even if they could get the technology working, so the X-33 was fully reusable, its ability to carry a payload would have been dramatically lower than a traditional multi-staged rocket.
In order to really achieve the dream of single stage to orbit, we need to step away from chemical rockets and move to a type of engine that can deliver thrust more efficiently.
We know that jets work more efficiently than rockets, because they only need to carry fuel. They pull oxygen in from the atmosphere, to burn the fuel. So one intriguing idea is to make a rocket that acts like a jet engine while in the atmosphere, and then acts like a rocket once it’s out in space.
And that’s the plan with the British Skylon rocket. It would take off from a regular runway, accelerate to about 6,600 km/h reaching an altitude of 26 kilometers. All this time, its SABRE engine would be pulling in oxygen from the atmosphere, combining it with hydrogen fuel.
An artist’s conception of Reaction Engines’ Skylon spacecraft. Credit: Reaction Engines
From this point, it would switch over to an internal liquid oxygen tank to provide oxidizer, and complete the flight to orbit. All the while using the same flexible SABRE engine. Once in orbit, it would release its 15-tonne payload and then return to Earth, landing on a runway like the space shuttle orbiter did. It’s a really creative idea.
Unfortunately, the development of the Skylon has taken a long time, with shrinking budgets limiting the amount of tests they’ve been able to do. If everything goes well, the first prototype might fly within a few years, so stay tuned to this story.
Another idea which has had some testing is the idea of a nuclear rocket. Unlike a chemical rocket, which burns fuel, and blasts it out the back for thrust, a nuclear rocket would carry a reactor on board. It would heat up some kind of working fuel, like liquid hydrogen, and then blast it out the back for propulsion.
The key elements of a NERVA solid-core nuclear-thermal engine. Credit: NASA
NASA did some tests a few decades ago with a nuclear thermal rocket called NERVA, and found that they could sustain high levels of thrust for very long periods of time. Their final prototype, provided continuous thrust for over 2 hours, including 28 minutes at full power.
NASA calculated that a nuclear-powered rocket would be roughly twice as efficient as a traditional chemical rocket. It would have a specific impulse of more than 950 seconds. But flying a nuclear rocket into space comes with a significant downside. Rockets explode. It’s bad when a chemical rocket explodes, but if a nuclear reactor detonated while making its way up through the atmosphere, it would rain down radioactive debris. For now, that’s considered too much of a risk; however, future interplanetary missions may very well use nuclear rockets.
There’s one more exotic fuel system that’s really exciting – metallic hydrogen. This solid form appears naturally at the heart of Jupiter, under the incredible pressure of the planet’s gravity. But earlier this year, researchers at Harvard finally created some in the lab. They used a tiny vice to squeeze hydrogen atoms with more force than the pressures at the center of the Earth.
Microscopic images of the stages in the creation of atomic molecular hydrogen: Transparent molecular hydrogen (left) at about 200 GPa, which is converted into black molecular hydrogen, and finally reflective atomic metallic hydrogen at 495 GPa. Credit: Isaac Silvera
It took an enormous amount of energy to squeeze hydrogen together that tightly, but in theory, once crafted, it should be relatively stable. And here’s the best part. When you ignite it, you get that energy back.
If used as a rocket fuel, it would provide a specific impulse of 1700 seconds. Compare that to the mere 450 from chemical rockets. A rocket powered by metallic hydrogen would easily get to orbit with a single stage, and travel efficiently to other planets.
Single Stage to Orbit rockets would be awesome. Science fiction has foretold it. That said, at the end of the day, whatever gets the most amount of payload into orbit for the lowest price is the most interesting rocket system. And right now, that’s staged rockets.
However, a bigger issue might be reliability and reusability. If you can get a single vehicle that takes off, travels to orbit and then returns to its launch pad, you can’t get anything simpler than that. No rockets to restack, no barges to navigate. You just use and reuse the same system again and again, and that’s a really exciting idea.
Right this moment, reusable staged rockets like SpaceX has the edge, but if and when the Skylon gets flying, I think we’ll have some serious competition.
Once we master metallic hydrogen, spaceflight will look very very different. Science reality will nearly match science fiction, and I’ll finally be able to fly my own personal Millennium Falcon.
