Time - What is time? Can we travel in time? When did time begin?
Welcome to Quatr.us Study Guides!

Time

Grandfather clock

Nobody knows what time is, or how it works. Time seems to be closely related to space, and it's possible that space and time are different ways of looking at the same thing. Some people think that time started with the Big Bang at the start of the universe, and that it will end when the universe collapses, though nobody knows when that will happen, or even if it will happen. If time started with the Big Bang, then that was about 13.7 billion years ago.

One way that time is related to space is that both of them depend on how fast you are moving. If you could travel very fast in a spaceship, close to the speed of light (186,000 miles a second), you would find that both space and time behaved very differently than they do in our ordinary lives. Time would pass much more slowly for you in your spaceship than it would for your sister back on Earth. When you got back, you might find that while you had only gotten one year older, she had gotten seven years older.

While you were in your fast spaceship, space would look different to you too. As you flew by a round planet like Neptune, it would look to you like a long oval instead.

These changes in time and space apply even at the slow speeds we can really travel at, but they don't change enough for you to notice. So for practical purposes today, we can treat time and space as if they were the same for everyone. But if we ever learn how to go really fast, close to the speed of light, then we will have to think about space and time very differently.

Bibliography and further reading about time:

Gravity
Space
Physics
Quatr.us home


LIMITED TIME OFFER FOR TEACHERS: Using this article with your class? Show us your class page where you're using this article, and we'll send you a free subscription so all your students can use Quatr.us Study Guides with no distractions! (Not a teacher? Paid subscriptions are also available for just $16/year!)
Please help other teachers and students find us: link to this page from your class page.
Karen Carr is Associate Professor Emerita, Department of History, Portland State University. She holds a doctorate in Classical Art and Archaeology from the University of Michigan. Follow her on Instagram or Twitter, or buy her book, Vandals to Visigoths.
Cite this page
  • Author: K.E. Carr
  • Title:
  • Site Name: Quatr.us Study Guides
  • Publisher: Quatr.us
  • Date Published:
Did you find what you needed? Ask your teacher to link to this page so other people can use it too! Send it in and win a Quatr.us "Great Page!" award!
Sign up for more free articles and special offers in Quatr.us' weekly newsletter:
We will never share your e-mail address unless you allow us to do so. View our privacy policy. Easy unsubscribe links are provided in every email.
Comment on This Article

Does your class page honor diversity, celebrate feminism, and support people of color, LBGTQ people, and people with disabilities? Let us know, and we'll send you a Diversity Banner you can proudly display!
Looking for more?
Quatr.us is loading comments...
(Comments will appear after moderation, if they are kind and helpful. Feel free to ask questions, and we'll try to answer them.)
Cite this page
  • Carr, K.E. . Quatr.us Study Guides, . Web. 28 March, 2017
ADVERTISEMENT