This article by Peter Watson, Carleton University originally appeared on the Conversation and is published here with permission.
Time travel makes regular appearances in popular culture, with innumerable time travel storylines in movies, television and literature. But it is a surprisingly old idea: one can argue that the Greek tragedy Oedipus Rex, written by Sophocles over 2,500 years ago, is the first time travel story.
But is time travel in fact possible? Given the popularity of the concept, this is a legitimate question. As a theoretical physicist, I find that there are several possible answers to this question, not all of which are contradictory.
The simplest answer is that time travel cannot be possible because if it was, we would already be doing it. One can argue that it is forbidden by the laws of physics, like the second law of thermodynamics or relativity. There are also technical challenges: it might be possible but would involve vast amounts of energy.
There is also the matter of time-travel paradoxes; we can — hypothetically — resolve these if free will is an illusion, if many worlds exist or if the past can only be witnessed but not experienced. Perhaps time travel is impossible simply because time must flow in a linear manner and we have no control over it, or perhaps time is an illusion and time travel is irrelevant.
Laws of physics
Since Albert Einstein’s theory of relativity — which describes the nature of time, space and gravity — is our most profound theory of time, we would like to think that time travel is forbidden by relativity. Unfortunately, one of his colleagues from the Institute for Advanced Study, Kurt Gödel, invented a universe in which time travel was not just possible, but the past and future were inextricably tangled.
We can actually design time machines, but most of these (in principle) successful proposals require negative energy, or negative mass, which does not seem to exist in our universe. If you drop a tennis ball of negative mass, it will fall upwards. This argument is rather unsatisfactory, since it explains why we cannot time travel in practice only by involving another idea — that of negative energy or mass — that we do not really understand.
Mathematical physicist Frank Tipler conceptualized a time machine that does not involve negative mass, but requires more energy than exists in the universe.
Time travel also violates the second law of thermodynamics, which states that entropy or randomness must always increase. Time can only move in one direction — in other words, you cannot unscramble an egg. More specifically, by travelling into the past we are going from now (a high entropy state) into the past, which must have lower entropy.
This argument originated with the English cosmologist Arthur Eddington, and is at best incomplete. Perhaps it stops you travelling into the past, but it says nothing about time travel into the future. In practice, it is just as hard for me to travel to next Thursday as it is to travel to last Thursday.
Resolving paradoxes
There is no doubt that if we could time travel freely, we run into the paradoxes. The best known is the “grandfather paradox”: one could hypothetically use a time machine to travel to the past and murder their grandfather before their father’s conception, thereby eliminating the possibility of their own birth. Logically, you cannot both exist and not exist.
Kurt Vonnegut’s anti-war novel Slaughterhouse-Five, published in 1969, describes how to evade the grandfather paradox. If free will simply does not exist, it is not possible to kill one’s grandfather in the past, since he was not killed in the past. The novel’s protagonist, Billy Pilgrim, can only travel to other points on his world line (the timeline he exists in), but not to any other point in space-time, so he could not even contemplate killing his grandfather.
The universe in Slaughterhouse-Five is consistent with everything we know. The second law of thermodynamics works perfectly well within it and there is no conflict with relativity. But it is inconsistent with some things we believe in, like free will — you can observe the past, like watching a movie, but you cannot interfere with the actions of people in it.
Could we allow for actual modifications of the past, so that we could go back and murder our grandfather — or Hitler? There are several multiverse theories that suppose that there are many timelines for different universes. This is also an old idea: in Charles Dickens’ A Christmas Carol, Ebeneezer Scrooge experiences two alternative timelines, one of which leads to a shameful death and the other to happiness.
Time is a river
Roman emperor Marcus Aurelius wrote that:
“Time is like a river made up of the events which happen, and a violent stream; for as soon as a thing has been seen, it is carried away, and another comes in its place, and this will be carried away too.”
We can imagine that time does flow past every point in the universe, like a river around a rock. But it is difficult to make the idea precise. A flow is a rate of change — the flow of a river is the amount of water that passes a specific length in a given time. Hence if time is a flow, it is at the rate of one second per second, which is not a very useful insight.
Theoretical physicist Stephen Hawking suggested that a “chronology protection conjecture” must exist, an as-yet-unknown physical principle that forbids time travel. Hawking’s concept originates from the idea that we cannot know what goes on inside a black hole, because we cannot get information out of it. But this argument is redundant: we cannot time travel because we cannot time travel!
Researchers are investigating a more fundamental theory, where time and space “emerge” from something else. This is referred to as quantum gravity, but unfortunately it does not exist yet.
So is time travel possible? Probably not, but we don’t know for sure!
CHICAGO (AP) — United Airlines has struck a deal with Elon Musk’s SpaceX to offer satellite-based Starlink WiFi service on flights within the next several years.
The airline said Friday the service will be free to passengers.
United said it will begin testing the service early next year and begin offering it on some flights by later in 2025.
Financial details of the deal were not disclosed.
The announcement comes as airlines rush to offer more amenities as a way to stand out when passengers pick a carrier for a trip. United’s goal is to make sitting on a plane pretty much like being on the ground when it comes to browsing the internet, streaming entertainment and playing games.
“Everything you can do on the ground, you’ll soon be able to do on board a United plane at 35,000 feet, just about anywhere in the world,” CEO Scott Kirby said in announcing the deal.
The airline says Starlink will allow passengers to get internet access even over oceans and polar regions where traditional cell or Wi-Fi signals may be weak or missing.
Sony has made it easy for Canadian consumers to preorder the PlayStation 5 Pro in Canada directly from PlayStation’s official website. Here’s how:
Visit the Official Website: Go to direct.playstation.com and navigate to the PS5 Pro section once preorders go live on September 26, 2024.
Create or Log in to Your PlayStation Account: If you don’t have a PlayStation account, you will need to create one. Existing users can simply log in to proceed.
Place Your Preorder: Once logged in, follow the instructions to preorder your PS5 Pro. Ensure you have a valid payment method ready and double-check your shipping information for accuracy.
Preorder Through Major Canadian Retailers
While preordering directly from PlayStation is a popular option, you can also secure your PS5 Pro through trusted Canadian retailers. These retailers are expected to offer preorders on or after September 26:
Best Buy Canada
Walmart Canada
EB Games (GameStop)
Amazon Canada
The Source
Steps to Preorder via Canadian Retailers:
Visit Retailer Websites: Search for “PlayStation 5 Pro” on the website of your preferred retailer starting on September 26.
Create or Log in to Your Account: If you’re shopping online, having an account with the retailer can speed up the preorder process.
Preorder in Store: For those who prefer in-person shopping, check with local stores regarding availability and preorder policies.
3. Sign Up for Notifications
Many retailers and websites offer the option to sign up for notifications when the preorder goes live. If you’re worried about missing out due to high demand, this can be a useful option.
Visit Retailer Sites: Look for a “Notify Me” or “Email Alerts” option and enter your email to stay informed.
Use PlayStation Alerts: Sign up for notifications directly through Sony to be one of the first to know when preorders are available.
4. Prepare for High Demand
Preordering the PS5 Pro is expected to be competitive, with high demand likely to result in quick sellouts, just as with the initial release of the original PS5. To maximize your chances of securing a preorder:
Act Quickly: Be prepared to place your order as soon as preorders open. Timing is key, as stock can run out within minutes.
Double-Check Payment Information: Ensure your credit card or payment method is ready to go. Any delays during the checkout process could result in losing your spot.
Stay Informed: Monitor PlayStation and retailer websites for updates on restocks or additional preorder windows.
Final Thoughts
The PlayStation 5 Pro is set to take gaming to the next level with its enhanced performance, graphics, and new features. Canadian gamers should be ready to act fast when preorders open on September 26, 2024, to secure their console ahead of the holiday season. Whether you choose to preorder through PlayStation’s official website or your preferred retailer, following the steps outlined above will help ensure a smooth and successful preorder experience.
For more details on the PS5 Pro and to preorder, visit direct.playstation.com or stay tuned to updates from major Canadian retailers.
Since the PlayStation 5 (PS5) launched four years ago, PlayStation has continuously evolved to meet the demands of its players. Today, we are excited to announce the next step in this journey: the PlayStation 5 Pro. Designed for the most dedicated players and game creators, the PS5 Pro brings groundbreaking advancements in gaming hardware, raising the bar for what’s possible.
Key Features of the PS5 Pro
The PS5 Pro comes equipped with several key performance enhancements, addressing the requests of gamers for smoother, higher-quality graphics at a consistent 60 frames per second (FPS). The console’s standout features include:
Upgraded GPU: The PS5 Pro’s GPU boasts 67% more Compute Units than the current PS5, combined with 28% faster memory. This allows for up to 45% faster rendering speeds, ensuring a smoother gaming experience.
Advanced Ray Tracing: Ray tracing capabilities have been significantly enhanced, with reflections and refractions of light being processed at double or triple the speed of the current PS5, creating more dynamic visuals.
AI-Driven Upscaling: Introducing PlayStation Spectral Super Resolution, an AI-based upscaling technology that adds extraordinary detail to images, resulting in sharper image clarity.
Backward Compatibility & Game Boost: More than 8,500 PS4 games playable on PS5 Pro will benefit from PS5 Pro Game Boost, stabilizing or enhancing performance. PS4 games will also see improved resolution on select titles.
VRR & 8K Support: The PS5 Pro supports Variable Refresh Rate (VRR) and 8K gaming for the ultimate visual experience, while also launching with the latest wireless technology, Wi-Fi 7, in supported regions.
Optimized Games & Patches
Game creators have quickly embraced the new technology that comes with the PS5 Pro. Many games will receive free updates to take full advantage of the console’s new features, labeled as PS5 Pro Enhanced. Some of the highly anticipated titles include:
Alan Wake 2
Assassin’s Creed: Shadows
Demon’s Souls
Dragon’s Dogma 2
Final Fantasy 7 Rebirth
Gran Turismo 7
Marvel’s Spider-Man 2
Ratchet & Clank: Rift Apart
Horizon Forbidden West
These updates will allow players to experience their favorite games at a higher fidelity, taking full advantage of the console’s improved graphics and performance.
Design & Compatibility
Maintaining consistency within the PS5 family, the PS5 Pro retains the same height and width as the original PS5 model. Players will also have the option to add an Ultra HD Blu-ray Disc Drive or swap console covers when available.
Additionally, the PS5 Pro is fully compatible with all existing PS5 accessories, including the PlayStation VR2, DualSense Edge, Pulse Elite, and Access controller. This ensures seamless integration into your current gaming setup.
Pricing & Availability
The PS5 Pro will be available starting November 7, 2024, at a manufacturer’s suggested retail price (MSRP) of:
$699.99 USD
$949.99 CAD
£699.99 GBP
€799.99 EUR
¥119,980 JPY
Each PS5 Pro comes with a 2TB SSD, a DualSense wireless controller, and a copy of Astro’s Playroom pre-installed. Pre-orders begin on September 26, 2024, and the console will be available at participating retailers and directly from PlayStation via direct.playstation.com.
The launch of the PS5 Pro marks a new chapter in PlayStation’s commitment to delivering cutting-edge gaming experiences. Whether players choose the standard PS5 or the PS5 Pro, PlayStation aims to provide the best possible gaming experience for everyone.
Preorder your PS5 Pro and step into the next generation of gaming this holiday season.
