Talk:1 E19 s and more

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Contents 1 Name 2 Various 3 Finite time 4 Contradiction 5 Iron-54 6 Longest finite time

[edit] Name

How about naming this page 1 E19 s and beyond?

The table is for durations of time, not specific points in time. So beyond may be misleading, I don't know... Whatever happens in terms of renaming, ALL references must be similarily updated to avoid double redirects... Egil 11:25 Apr 1, 2003 (UTC)

Also, although here pretty clear, in general beyond might be ambiguous because it depends on direction: it can mean more or less (what means 1 sec and beyond?). - Patrick 11:51 Apr 1, 2003 (UTC)

Wouldn't 1 E19 s and longer be more correct in relation to duration? --212.105.25.105 02:02, 27 June 2006 (UTC)

[edit] Various

About black holes decaying due to Hawking radiation: an article on astronomy in a (german) copy of Scientific American I own, written by Lawrence M. Krauss and Glenn D. Starkmann (both from Case Western Reserve University in Cleveland), states that this is only due to happen at ~10⁹⁸ years, not 10⁶⁴. Does anyone have references that would support either estimate? -- Schnee 01:14, 5 Aug 2003 (UTC)

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Not sure where the figure 10^10^26 for decay to iron comes from. I believe the correct value is the far more modest 10^1500. Will change if no one has a credible source for the larger value. (Also, I hadn't seen the 10^10^76, but I think black hole talk is still mostly speculation.) Mentioning this is contingent on no proton decay might be important too. -- VV 09:49, 6 Oct 2003 (UTC)

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If I remember correctly, (10^10)^76 is the time in which a supermassive black hole evaporates in Hawking radiation, i.e. after that time there is no material left in the universe.

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Be careful with powers of powers, (10^10)^76 = 10^760 and not 10^(10^76).

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Ahh, stupid error :( Shouldn't edit tired... Jyril 17:00, 18 Jun 2004 (UTC)

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What does "time until positrons and electrons form positronium" mean? Positronium decays with a half-life about 10^-7 seconds.

I agree it doesn't make sense. Removed. _R_ 14:12, 12 Aug 2004 (UTC)

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Is not the physicist referenced at 10^1500 years, 10^several million million million years, and in the external links section, named Freeman Dyson, and not Dyson Freeman? Justin Z 19:40, 30 November 2006 (UTC)

[edit] Finite time

Has it been proven (not just believed by a vast majority of scientists, but PROVEN that the entire time the universe will be before it ceases to exist is finite?? 66.245.23.71 00:32, 12 Nov 2004 (UTC)

Your question includes the assumption that the universe will cease to exist, which is not proven ;). Seriously, how do you think this could be proven? See falsifiability and scientific method. 193.171.121.30 16:37, 6 March 2006 (UTC)

The question is also strangely illogical. If then universe ever ceases to exist, it must necessarily have a finite lifetime (assuming creation in the finite past). But if the universe has an infinite lifetime, it cannot ever cease to exist. You cannot assume both a ceasing universe and an infinite lifetime simultaneously.
—Herbee 06:19, 18 January 2007 (UTC)

[edit] Contradiction

Confused: At 10^64 and 10^100 years we have black holes decaying by the Hawking process, but at (10^10^26) years we have matter collapsing into black holes again. Wouldn't these black holes again decay? Once and for all -- is the end state of the universe one big black hole (all the black holes merge) or uniform low-energy photons (Heat death of the universe)? —The preceding unsigned comment was added by 65.57.245.11 (talk • contribs) 5 December 2004.

First, the currently existing solar black holes will evaporate. Then the supermassive black holes at the centers of galaxies will evaporate. Eventually, if the universe doesn't expand too quickly, all the remaining "loose" matter in the universe will collapse again to form a new "universal black hole". You're right, though--this final black hole would evaporate too, eventually, leaving nothing but photons and perhaps a quantity of matter too small to reach critical mass (which might or might not undergo proton decay). But the hypothetical eventual existance of a universal black hole is dependent on the dark energy being too small to prevent the collapse of the matter, but large enough to prevent the collapse of the universe. --71.146.104.66 01:33, 14 June 2006 (UTC)

[edit] Iron-54

3.1 × 10²² years – estimated half-life of iron-54

That's simply untrue: iron-54 is stable. Some sources quote a lower limit on the order of 10^22.5 years, but that's not an estimated half-life. In fact, it's consistent with stability.
—Herbee 06:28, 18 January 2007 (UTC)

[edit] Longest finite time

This time (10^10^76 years) … is likely the longest finite time ever explicitly calculated by a physicist.

If true, that claim would be unverifyable and thus unencyclopedic. But the very next paragraph mentions a longer timespan (10^10^10^10^10^1.1 years), which immediately falsifies this silly claim.
—Herbee 06:41, 18 January 2007 (UTC)