# How does science knows what is the early universe?

I've read about Hubble seeing the brightest quasar in the early universe. Question is, how does science knows what is early and what is late?

Please correct me if I'm wondering, but after the big bang, everything went in all directions equally. How do we know what direction is the center of the big bang? And continuing on the line of thought, is "early universe" considered closer to the origin of the big bang or further away?

• Please link to or cite where you read about Hubble seeing the brightest quasar. The second part is a duplicate so I've edited to remove it. – James K Jan 12 at 20:48
• The article in question is not related to the topic I am asking about. And I do believe that the second part of the question (that you removed) is not a duplicate. – KingsInnerSoul 5 hours ago
• Possible duplicate of What is in the center of the universe? – James K 36 mins ago

I assume you're referring to the recent press release about the quasar J043947.08+163415.7, observed recently using Hubble. The paper about the observations details how the authors measured the distance to the quasar, by calculating its redshift, a quantity that describes how the wavelength of light appears to change based on whether the object is moving relative to an observer. On cosmological scales, redshift can then be converted to distances. We usually see quasars at $$z>0.1$$.
This emission line was observed to have a different wavelength than it would if the quasar was at rest, enabling the astronomers to calculate its redshift: $$z=6.511\pm0.003$$.