Sleep isn’t uniform. Once we fall asleep, our bodies follow a sleep cycle, lasting 90-120 minutes on average. Our total sleep is made up of several rounds of this cycle. Each cycle contains four stages. The first three stages are known as non-rapid eye movement (NREM) sleep, and the final stage is known as rapid eye movement (REM) sleep.

Stage 1 NREM
Recognised as the “dozing off” stage, it lasts around one to five minutes. Muscles relax and your heart rate, breathing, and eye movements begin to slow down, as do your brain waves, which are more active when you are awake. It’s easy to wake someone up during this stage, but undisturbed, they can move quickly into stage 2.

Stage 2 NREM
It’s characterized by deeper sleep as your heart rate and breathing rates continue slowing down. Eye movements cease and body temperature decreases. Apart from some brief moments of higher frequency electrical activity, brain waves also remain slow. Stage 2 is typically the longest of the four sleep stages.

Stage 3 NREM
This stage plays an important role in making you feel refreshed and alert the next day. Heartbeat, breathing, and brain wave activity all reach their lowest levels, and the muscles are as relaxed as they will be. This stage lasts longer in initial cycles, decrease in duration over the following cycles.

REM
It occurs ~90 minutes after falling asleep. Your eyes move back and forth rather quickly under your eyelids. Breathing rate, heart rate, and blood pressure begins to increase. Dreaming typically occurs during REM sleep, and your arms and legs become paralyzed – it’s believed this is intends to prevent us from physically acting out our dreams. The duration of each REM stage increases by cycle, the inverse of stage 3 NREM. Studies linked REM sleep to memory consolidation, the process of converting recent experiences into long-term memories. The duration of the REM stage decrease as we age, causing us to spend more time in the NREM stages.

Moments where we briefly wake during the night, but not remember them, are known as “W” stages.

Internet feels like a human right now: providing access to information, communication, and life admin tools (at the least). There’s around 1m people in NYC that don’t have access to internet, due to cost barriers driven to the oligopolistic market of providers. They won’t invest in areas where it’s deemed a low return on investment.

NYC Mesh is a community run organisation, run by volunteers, helping people get access to high speed internet. Super nodes are fibre-connected and act as gateways, repeaters then beam internet to neighbourhood nodes, which relay it to a user’s individual router. It becomes a web of interconnected routers and repeaters keeping internet access operational. Users cover the cost of installation if they have the means, it still goes ahead if they don’t. Everything else is run on donations. It’s free for those who can’t financially support the cause.

Security-wise, the mesh router is firewalled from a user’s local network meaning it’s not possible to reach beyond the mesh router to a user’s local access network (LAN). The mesh internet connection and traffic between nodes is encrypted using WPA2.

To understand why the world currently burns fossil fuels, it helps to follow the money.

Energy demand has long tracked economic growth. So much so that for the past two centuries, the amounts of energy that economies need have increased virtually in lockstep with the amounts of wealth that economies create. And, to a remarkable degree, wealth creation has depended on a society’s proficiency at burning things.

In 1800, the fuel of choice was biomass, such as wood from fallen trees. Biomass was highly inefficient as fuel, as almost all of its embodied energy was lost in its burning (low conversion). Still, before widespread industrialisation, the conversion loss was bearable; generally, there was enough wood to burn to make economies grow. The resulting wealth creation wasn’t enormous, but it was pointing up.

Then, at the turn of the 20th century, rates of both energy demand and economic growth took off. From 1900 to 1950 – as horses gave way to cars, oil lamps to electric lighting, and ice boxes to refrigerators – primary energy demand nearly doubled. Economic growth rates soared as well; in the United States, GDP per capita in 1950 was more than twice that of 1900.¹ For that level of wealth creation, burning trees and other forms of biomass wouldn’t quite suffice.

Enter fossil fuels, whose energy conversion was far greater than biomass. The 20th century’s embrace of petroleum and coal sent production and consumption into overdrive. Fossil fuels lose about 40-70% of their embodied energy when converted into electrical energy – a lot, but not a lot compared to the near-total loss incurred by burning wood. It was simply more efficient while also abundant. Source: McKinsey

Until renewable energy tech is widely innovated and harnessed, unfortunately it’s not as practically abundant and financially efficient as fossil fuels. However, it’s promising that electricity generated worldwide in 2020 from renewable source, grew to 29%. Its adoption has a flywheel effect, entrenching renewable energy production through economies of scale and the compounding advancements.

I think it may have always been about the economics. Once renewables are markedly cheaper and more practical than fossil fuels, we’ll have entered a new epoch. Economies will fall in line…their growth depends on it.