The Times Australia
The Times World News

.
The Times Real Estate

.

what would happen if someone moved at twice the speed of light?

  • Written by Sam Baron, Associate professor, Australian Catholic University

I’m curious about what will happen if, hypothetically, someone moves with speed (that is) twice the speed of light? – Devanshi, age 13, Mumbai

what would happen if someone moved at twice the speed of light?

Hi Devanshi! Thanks for this great question.

As far as we know, it’s not possible for a person to move at twice the speed of light. In fact, it’s not possible for any object with the kind of mass you or I have to move faster than the speed of light.

However, for certain strange particles, travelling at twice the speed of light might be possible – and it might send those particles back in time.

A universal speed limit

One of our best physical theories at the moment is the theory of relativity[1], developed by Albert Einstein. According to this theory, the speed of light operates as a universal speed limit on anything with mass.

Specifically, relativity tells us that nothing with mass can accelerate past the speed of light.

To accelerate an object with mass, we have to add energy. The faster we want the object to go, the more energy we’ll need.

The equations of relativity tell us that anything with mass – regardless of how much mass it has – would require an infinite amount of energy to be accelerated to the speed of light.

But all of the sources of energy we know of are finite: they are limited in some respect.

Indeed, it’s plausible the Universe only contains a finite amount of energy. That would mean there isn’t enough energy in the Universe to accelerate something with mass up to the speed of light.

Since you and I have mass, don’t expect to be travelling at twice the speed of light anytime soon.

Blue beams of light rushing past signify a fast moving object going through space
According to Einstein, nothing bulky such as an object or human could accelerate faster than the speed of light. Shutterstock

Tachyons

This universal speed limit applies to anything with what we might call “ordinary mass”.

There are, however, hypothetical particles called tachyons[2] with a special kind of mass called “imaginary mass”.

There is no evidence tachyons exist. But according to relativity, their possible existence can’t be ruled out.

If they do exist, tachyons must always be travelling faster than the speed of light. Just as something with ordinary mass can’t be accelerated past the speed of light, tachyons can’t be slowed down to below the speed of light.

Some physicists believe that if tachyons exist, they would constantly be travelling backwards in time. This is why tachyons are associated with time travel in many science fiction books and movies.

There are ideas that we might someday harness tachyons to build a time machine[3]. But for now this remains a distant dream, as we don’t have the ability to detect potential tachyons.

Read more: Curious Kids: is time travel possible for humans?[4]

Shortcuts?

It’s disappointing we can’t travel faster than the speed of light. The nearest star to us, other than the Sun, is 4.35 light years away. So, travelling at the speed of light, it would take more than four years to get there.

The farthest star[5] we’ve ever detected is 28 billion light years away. So you can pretty much give up on charting the entire Universe.

That said, relativity does allow for the existence of “wormholes[6]”.

A wormhole is a shortcut between any two points in space. While a star might be 4.5 light years away in normal terms, it might only be a few hours away via a wormhole.

If there are any actual wormholes, they would let us travel great distances in a very short period of time – allowing us to get to the farthest reaches of the universe within a single lifetime.

Unfortunately, like tachyons, wormholes remain entirely hypothetical.

Illustration showing a hypothetical wormhole open in space, bending spacetime around it. You can think of a wormhole as a tunnel with two ends opening up to different points in spacetime. Shutterstock

Strange possibilities

Despite the fact we can’t genuinely travel faster than light, we can still try to imagine what it would be like to do so.

By thinking in this way, we are engaging in “counterfactual thinking[7]”. We are considering what things would, or might, be like if reality was different in some way.

There are many different possibilities we could consider, each with a different set of physical principles.

So we can’t say with any certainty what would happen if we were able to travel faster than light. At best, we can guess what might happen. Would we start to travel back in time, as some scientists think tachyons might do?

I’ll leave it to you and your imagination to come up with some ideas!

References

  1. ^ theory of relativity (theconversation.com)
  2. ^ tachyons (www.space.com)
  3. ^ build a time machine (theconversation.com)
  4. ^ Curious Kids: is time travel possible for humans? (theconversation.com)
  5. ^ farthest star (theconversation.com)
  6. ^ wormholes (theconversation.com)
  7. ^ counterfactual thinking (www.reddit.com)

Read more https://theconversation.com/curious-kids-what-would-happen-if-someone-moved-at-twice-the-speed-of-light-183043

The Times Features

Discover the Charm of a Girl's White Dress

Key Highlights Timeless elegance: White dresses feel pure and have classic charm. They are perfect for many types of events. Versatile styles: You can pick from lace, embroid...

Top Medical Grade Red Light Therapy Devices in Australia

Key Highlights Lumitter™ has advanced red light therapy devices that combine new ideas with wellness. Red light therapy helps lower pain and swelling and boosts skin health. ...

Why Regional Small Businesses in Bendigo Deserve Better Access to Finance in 2025

In the heart of regional Victoria, Bendigo has long stood as a beacon of innovation, resilience and community spirit. As we step further into 2025, the importance of nurturing sm...

Is It Time for a Deep Cleaning? Signs You Shouldn’t Ignore

Most people know they should visit the dentist for a regular check-up and cleaning every six months. But sometimes, a standard cleaning isn’t enough. When plaque and tartar build...

The Hidden Meaning Behind Popular Engagement Ring Cuts

When it comes to engagement rings, the cut of the diamond is not just about aesthetics. Each shape carries its own symbolism and significance, making it an important decision for...

Annual Health Exams in the Office: How They Can Reduce Sick Days and Healthcare Costs

Regular health check-ups, especially annual health exams in the office, can significantly impact the overall well-being of your workforce. A proactive approach to employee health...

Times Magazine

The Essential Guide to Transforming Office Spaces for Maximum Efficiency

Why Office Fitouts MatterA well-designed office can make all the difference in productivity, employee satisfaction, and client impressions. Businesses of all sizes are investing in updated office spaces to create environments that foster collaborat...

The A/B Testing Revolution: How AI Optimized Landing Pages Without Human Input

A/B testing was always integral to the web-based marketing world. Was there a button that converted better? Marketing could pit one against the other and see which option worked better. This was always through human observation, and over time, as d...

Using Countdown Timers in Email: Do They Really Increase Conversions?

In a world that's always on, where marketers are attempting to entice a subscriber and get them to convert on the same screen with one email, the power of urgency is sometimes the essential element needed. One of the most popular ways to create urg...

Types of Software Consultants

In today's technology-driven world, businesses often seek the expertise of software consultants to navigate complex software needs. There are several types of software consultants, including solution architects, project managers, and user experienc...

CWU Assistive Tech Hub is Changing Lives: Win a Free Rollator Walker This Easter!

🌟 Mobility. Independence. Community. All in One. This Easter, the CWU Assistive Tech Hub is pleased to support the Banyule community by giving away a rollator walker. The giveaway will take place during the Macleod Village Easter Egg Hunt & Ma...

"Eternal Nurture" by Cara Barilla: A Timeless Collection of Wisdom and Healing

Renowned Sydney-born author and educator Cara Barilla has released her latest book, Eternal Nurture, a profound collection of inspirational quotes designed to support mindfulness, emotional healing, and personal growth. With a deep commitment to ...

LayBy Shopping