I'm creating a sci-fi world similar to ours roughly 50 years in the future. Unobtanium, a futuristic metal and fuel source, was discovered in 2020. Its broad utility led to rapid advances across all parts of industry, but especially spaceflight, which is now commonplace for government / business leaders and military operations. However, even occasional spaceflight is beyond the means of average families.
My goal is to have have a dense cloud of debris completely blanketing the Earth. The main requirements are:
- The debris needs to not exist around present-day Earth yet be fully formed within a couple hundred years, 50 years being preferable.
- Ideally the debris would be of varying sizes, from micrometeorites to large rocks several hundred meters in diameter. It is most important to have debris in the tens-of-meters range.
- The average debris density is flexible, but, at its densest, flying through should be risky without planning or active piloting. It would be ideal if debris were present at every latitutde.
- The event that causes the debris cannot radically affect human society. Things like destruction of artifical satelites or small climate change (changes to day length, tides, global temperatures, etc.) are fine, but not things like "all humans are forced to live in underground bunkers".
- To be clear, I'm not interested in long term stability. The debris only needs to be around long enough for it to be part of "everyday life" for spacefarers.
- Bonus points if your soultion can explain the sudden appearence of large but expendable amounts of unobtanium (~10,000,000 m^3) on Earth's surface and in the debris field in 2020.
My first approach was to have an asteroid impact Earth’s moon, which would be convenient for other plot reasons, but after looking into it, it seems an impact strong enough to create the sort of debris density I need would have lots of appocalyptic side effects for the residents of Earth down below.
Another approach I considered was having people attempt to break up an inbound asteroid before it stuck Earth, but it seems like a object of mass sufficent to cause the sort of debris field I want would be imposssible to stop without causing significant damage to the Earth.
TLDR: How can I explain the sudden appearence of a dense debris field around earth?