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I would give anything to be able to jump back in time to watch humanity grow. There is so much history pre-metal eras that we simply know nothing about.

lumost 3y ago
Do we even know when the metal eras arrived? It seems like most bronze/iron artifacts would have been destroyed by time if they existed prior to 2-4K BC. In particular, iron /steel artifacts tend towards rust on short timescales.
- wswope 3y ago
  Yes; metalworking is readily detectable through slag and furnace remains.
  - 082349872349872 3y ago
    We can even distinguish if something that looks like it might have been a firepit actually was one by checking the induced magnetisation via the Curie temperature.
  - lumost 3y ago
    Isn't the caveat here that we would need an archeological site which was last used within the >5k years ago? how many burn pits of any type have been detected on this time scale?
    - wswope 3y ago
      The number of discovered paleolithic burn sites easily ranges into the thousands. Later occupation of a site wouldn’t change much - substantially different eras are easy to identify by relative stratigraphy, and fires hot enough for metalworking can typically be loosely dated by their archaeomagnetic signatures.
- wolverine876 3y ago
  There is plenty of evidence, including in written records (writing dates back ~5,200 yrs). We have actual stone tools from millions of years ago; metal tools from thousands of years ago should be relatively abundant. Take a look online and you can find much written about it. Encyclopedia Britannica is often a good starting point, or the literature review in a scholarly article (via scholar.google.com).
  - lumost 3y ago
    Apologies if this question is out of ignorance. But with a stone tool made out of something such as granite, isn't it correct that the only requirement is that the tool is not unduly compressed/crushed for it to survive 10s of thousands to millions of years? Metal tools need to avoid oxidation as well which doesn't seem tractable over timelines greater than a few thousand years.
    - wolverine876 3y ago
      Good questions. I don't happen to know, but don't metals survive in the earth - whence they are mined - for essentially eternity?
      - dbingham 3y ago
        Metal ores are usually oxidized versions of the metal that need to be refined in someway. In other words, the metal in the Earth has already rusted.
    - throwup238 3y ago
      > But with a stone tool made out of something such as granite, isn't it correct that the only requirement is that the tool is not unduly compressed/crushed for it to survive 10s of thousands to millions of years? Stone tools were made mostly from flint due to the way it cleaves with sharp edges. Granite and other stone tools weren't used until the neolithic as ground stones. In order to survive for that long, stone tools mostly just had to avoid moving water. Anything that fell into a river or ocean would be worn away quickly (like beach glass). Unfortunately, until the end of the last glacial period (~12,000 years ago), the sea level was much lower than it is today and most human habitation has long since been flooded by the melting glaciers. Underwater archaeology is a new field that's growing in importance but it's slow going and the ocean is much more dynamic that dry land.

lumost 3y ago

Do we even know when the metal eras arrived? It seems like most bronze/iron artifacts would have been destroyed by time if they existed prior to 2-4K BC. In particular, iron /steel artifacts tend towards rust on short timescales.

wswope 3y ago
Yes; metalworking is readily detectable through slag and furnace remains.
- 082349872349872 3y ago
  We can even distinguish if something that looks like it might have been a firepit actually was one by checking the induced magnetisation via the Curie temperature.
- lumost 3y ago
  Isn't the caveat here that we would need an archeological site which was last used within the >5k years ago? how many burn pits of any type have been detected on this time scale?
  - wswope 3y ago
    The number of discovered paleolithic burn sites easily ranges into the thousands. Later occupation of a site wouldn’t change much - substantially different eras are easy to identify by relative stratigraphy, and fires hot enough for metalworking can typically be loosely dated by their archaeomagnetic signatures.
wolverine876 3y ago
There is plenty of evidence, including in written records (writing dates back ~5,200 yrs). We have actual stone tools from millions of years ago; metal tools from thousands of years ago should be relatively abundant. Take a look online and you can find much written about it. Encyclopedia Britannica is often a good starting point, or the literature review in a scholarly article (via scholar.google.com).
- lumost 3y ago
  Apologies if this question is out of ignorance. But with a stone tool made out of something such as granite, isn't it correct that the only requirement is that the tool is not unduly compressed/crushed for it to survive 10s of thousands to millions of years? Metal tools need to avoid oxidation as well which doesn't seem tractable over timelines greater than a few thousand years.
  - wolverine876 3y ago
    Good questions. I don't happen to know, but don't metals survive in the earth - whence they are mined - for essentially eternity?
    - dbingham 3y ago
      Metal ores are usually oxidized versions of the metal that need to be refined in someway. In other words, the metal in the Earth has already rusted.
  - throwup238 3y ago
    > But with a stone tool made out of something such as granite, isn't it correct that the only requirement is that the tool is not unduly compressed/crushed for it to survive 10s of thousands to millions of years? Stone tools were made mostly from flint due to the way it cleaves with sharp edges. Granite and other stone tools weren't used until the neolithic as ground stones. In order to survive for that long, stone tools mostly just had to avoid moving water. Anything that fell into a river or ocean would be worn away quickly (like beach glass). Unfortunately, until the end of the last glacial period (~12,000 years ago), the sea level was much lower than it is today and most human habitation has long since been flooded by the melting glaciers. Underwater archaeology is a new field that's growing in importance but it's slow going and the ocean is much more dynamic that dry land.