# How Far Are We From the Edge of the Universe? [duplicate]

Following the Big Bang the Universe continues to expand, presumably and roughly equally in all directions. It is understood that the Big Bang occurred 13.798 ± 0.037 billion years ago.

Is there any way for us to know how far we are away from the nearest edge of the expansion front of the Big Bang?

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## marked as duplicate by astromax, TildalWave, Eduardo Serra, RhysW♦Feb 6 '14 at 8:45

If it helps, this is really just a corollary to this question: Where is the center of the universe? –  Robert Cartaino Jan 16 '14 at 15:06

According to the seven-year WMAP results [pdf], the proper distance to the surface of last scattering that emitted the cosmic microwave backgrounds is approximately $46.0\,\mathrm{Gly}$, which is basically as far as we can actually see. The true cosmological horizon slightly more distant that this, closer to $46.6\,\mathrm{Gly}$. What's beyond the horizon is not known.
Another cosmologically significant distance scale is the Hubble radius, at which the galaxies comoving with the Hubble flow recede from us at the speed of light. It is $c/H_0 = 13.9\pm0.3\,\mathrm{Gly}$.
@adrianmcmenamin: The scattering that produced the CMBR we see definitely happened "there", since light took over $13\,\mathrm{Ga}$ to reach us "here". Scattering also happened "here", but we don't see that light, so it's not relevant. And by $46\,\mathrm{Gly}$, I mean proper distance in the comoving frame. Additionally, in this context the "cosmological principle" winds up being "the universe is homogeneous and isotropic." It's only meant to apply on the large scale, so there's a kind of "averaging" involved. –  Stan Liou Jan 18 '14 at 19:45