I think they are referring to as trees die and decay, they re-emit most of their stored CO2. How much net storage happens depends on soil building/erosion processes.

> A mature forest absorbs no net CO2.

It does if you harvest the mature trees, turn them into durable wood products and replant. Municipal sludge, the stuff removed by water treatment plants, can be used to fertilize the trees replanted, if the natural soil gets too depleted on its own.

Jet engines work fine with biofuels. It's been tested already. Only downside is your airports will smell like french fries.

Planting trees and then making durable wood products from them has a *negative* cost per ton. Planting seedlings is very cheap in bulk, and mature trees fetch a decent price in lumber, plywood, etc. Just make sure the houses and furniture you make from it will last, not particleboard junk that ends up in a landfill and decomposes.

So as a society, we should be encouraging as much tree planting as possible before investing in other carbon capture schemes.

Under the Texas anti-censorship law, Telecoms will be *required* to carry the content. No moderation or filtering allowed.

Rockets won the space race because ballistic missiles already existed. New ideas have to compete with the established system. Two that have succeeded are gravity assists and electric propulsion.

Rockets don't need a whole lot of infrastructure to fly. A flame-proof launch pad and a tank farm to fuel them. Some of the others, like Giant Space Guns*, need bigger infrastructure, and therefore high traffic rates to justify the construction cost.

*I was the study manager at Boeing for a giant space gun concept. I know way too much about the details.

Oh yeah, I knew that guy. I did space propulsion work for Boeing and it is a small community. We went to the same conferences and such.

Today you can get lasers up to the 1 MW power level. For significant payload to orbit, you need 1 GW or more (1000 times higher). We used to joke "there is no problem that cannot be solved with the suitable application of a 1.21 Gigawatt laser".

Orion will never be allowed anywhere near Earth. It can become a weapon of mass destruction by setting off bombs less often and hovering over a country you want to destroy. Probably Neptune distance to kick off interstellar missions is the nearest you could get people to allow it.

Something 42,000 km long is not "surprisingly practical". It is on the same scale as the US Interstate Highway System. An 1170 km long rotating cable (skyhook) with 2.4 km/s tip speed is much more feasible, and can provide partial function while under construction. The particular numbers chosen provide a comfortable 1g acceleration at the tips.

Knocking 2.4 km/s off the speed required by the rocket makes single stage ones with a good payload fraction feasible. On the return trip, they just release from the cable tip, and have half the energy to dissipate with a heat shield. So that becomes easier too.

> We use chemical rockets because nobody has figured out a better alternative.

I speak as a "rocket scientist" (space systems engineer) who worked for Boeing and NASA. We *have* figured out better alternatives, but modified ballistic missiles got us to orbit first and have dominated the market.

Hypersonic gas guns can reach Mach 5-13, depending how many g's you can tolerate, and guns are pretty reusable, but you want a *lot* of traffic to justify the cost of building them. Such guns already exist in smaller versions, mostly used for research. Orbiting skyhooks and electric propulsion work for orbit and above. Electric propulsion is actually already in use, but the power levels are still too low for heavy payloads. All of these could be developed if one billionaire or a bunch of venture capitalists threw money at them.

Gravity assists are better than rockets, and we use them a lot for planetary missions. They are "free* in the sense of not needing much fuel (just for alignment), but actually exchange energy with the body you are flying past.

Chemical rockets reached the practical limit of performance in 1962, when the first H2/O2 stages were built. The only improvements since then have been marginal ones in structures. Chemistry doesn't change, so the 90% of the rocket that is fuel won't ever get better.

> "Should the accelerating launch platform end its runs at the top of Everest or Kilimanjaro?"

Mt. Cayambe in Ecuador. It is the highest point on the Equator. Since the Earth has an equatorial bulge, it is the farthest point from the center of the Earth and thus the nearest to space. You also get the maximum benefit of the Earth's rotation. Lastly, the mountain has reasonable slopes for both short (2 km) high acceleration (1000 g's) systems, and long (15 km) lower g systems that can carry people and space hardware (6 g's max)

China is capitalism, with dictators skimming off the top and making sure nobody is powerful enough to depose them. Sort of like organized crime where one gang won. Russia *is* organized crime, but the criminals don't know how to manage a modern economy. The Chinese leadership at least are technocrats who have a clue.

I've done work on space elevators for Boeing and NASA. Although the *theoretical* strength of carbon nanotubes is high enough for a space elevator, real materials are nowhere near the theoretical strength. That requires no defects at an atomic level, which never happens.

Fortunately, a newer design than space elevators (1894), the "skyhook" (1986) can accomplish most of the benefits with 50 times less cable, and today's materials. It doesn't reach all the way to the ground, but it doesn't have to. A single stage rocket flies to a platform at the end of the skyhook at 1g. Conveniently, Spacex has proven landing on a platform (their drone ships) at 1 g, with high accuracy. The fact that the platform is attached to an orbiting cable rather than floating on the ocean makes no difference to a guidance system.

Rockets are absurdly powerful machines. For example the Falcon 9's exhaust power is 13.5 GW. High power lasers of the type you want top out at around 1 MW, thousands of times less. So they are only useful for launching 1 kg objects.

On the other hand, a 10 meter pipe at car tire pressure (30 psi) provides *more* force than the Falcon 9. A sufficiently long blowpipe can accelerate heavy objects to significant speeds.

Unfortunately his starting point is an android that looks less realistic than a wax museum replica of himself.

The EIA "Electric Power Monthly" tabulates all the sources of US electricity. They have a column for "small scale generation" that covers rooftop solar, among other things. Utility power (over 1 MW) are required to report their data. Smaller installations are not, and if they use the power internally, it never makes it to a transmission line where it can be measured.

So that column is an estimate, based on sales, installations and other data sources. If a user has "net metering" with their utility (gets credit for pushing power to the grid), the utility can measure the "Negawatts" they receive from running the meter backwards. But that doesn't tell them what a home has used internally before it sends power out to the power company.

https://www.eia.gov/electricit...