# How fast is the universe expanding? + astrophysics question **URL:** \ **Category:** Factual Questions\ **Created:** [August 11, 2003, 3:53am UTC](https://boards.straightdope.com/t/how-fast-is-the-universe-expanding-astrophysics-question/194317 "2003-08-11T03:53:53Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![culov](https://avatars.discourse-cdn.com/v4/letter/c/e79b87/32.png) [@culov](https://boards.straightdope.com/u/culov)\ **Post date:** [August 11, 2003, 3:53am UTC](https://boards.straightdope.com/t/how-fast-is-the-universe-expanding-astrophysics-question/194317/1 "2003-08-11T03:53:53Z")
So… How fast is the universe expanding? Would it be incorrect to assume that new planets/stars or whole galaxies (basically anything but empty space) are being created every so often? If yes, how often (ie 500 planets a day… im sure that would be really really wrong)? Im just trying to visualize how big the universe actually is so could i just say that the big bang occured about 20 billion years ago and multiply that by the speed that its currently expanding, or does the speed constantly change? Finally, how (theoretically) is a wormhole created? ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [August 11, 2003, 4:19am UTC](https://boards.straightdope.com/t/how-fast-is-the-universe-expanding-astrophysics-question/194317/2 "2003-08-11T04:19:31Z")
> [@](#): > > \*Originally posted by culov \* > \*\*So… How fast is the universe expanding? Would it be incorrect to assume that new planets/stars or whole galaxies (basically anything but empty space) are being created every so often? If yes, how often (ie 500 planets a day… im sure that would be really really wrong)? > > Im just trying to visualize how big the universe actually is so could i just say that the big bang occured about 20 billion years ago and multiply that by the speed that its currently expanding, or does the speed constantly change? > > Finally, how (theoretically) is a wormhole created? \*\* Try [this site](http://slashdot.org/articles/99/05/26/1236211.shtml). And there are many others if you search for “Hubble’s Constant” or the age of the universe. The rate at which the universe is expanding is a function of how far away you are talking about. The further away, the faster. If the currently accepted value of Hubble’s Constant is about right, then we won’t be able to measure anything older than about 15 billion years because at that age/distance the expansion rate is near the speed of light. This thing is in a little bit of a state of flux right now because of some recent discoveries about the speed at which some galaxies, or something, have been measured as moving away. Maybe some physicist familiar with the current state of the physics will be along to help with that. ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [August 11, 2003, 4:37am UTC](https://boards.straightdope.com/t/how-fast-is-the-universe-expanding-astrophysics-question/194317/3 "2003-08-11T04:37:05Z")
> [@](#): > > If the currently accepted value of Hubble’s Constant is about right, then we won’t be able to measure anything older than about 15 billion years because at that age/distance the expansion rate is near the speed of light. I think new, much more exact studies have pegged the age of the universe at around 13.7 billion years. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [August 11, 2003, 5:16am UTC](https://boards.straightdope.com/t/how-fast-is-the-universe-expanding-astrophysics-question/194317/4 "2003-08-11T05:16:40Z")
Courtesy of [Wilkinson Microwave Anisotropy Probe (WMAP)](http://map.gsfc.nasa.gov/m_mm/mr_limits.html): > [@](#): > > Universe is 13.7 billion years old with a margin of error of close to 1%. > Expansion rate (Hubble constant) value: Ho= 71 km/sec/Mpc (with a margin of error of about 5%)