FTA: Some worry about water use or earthquakes from drilling.

Uh huh. And where were all of these people who worry about earthquakes when the fracking boom was gearing up?

Also, fracking creates tons and tons of contaminated wastewater – which is injected into the ground.

Some municipal airports still sell only leaded aviation fuel (for prop planes).

Prop plane owners don't want to pay for the under-$1000 upgrades to their engines to allow the use of unleaded gas. The aviation lobby is strong.

FTA: "With our decision to focus on ride-hailing, we'll push back the timeline on our commercial and operational efforts on trucking, as well as most of our technical development on that business unit," the company said in a statement.

Any engineer worth their salt knows that you don't go trying to solve the hardest problem first, if you want your company to survive. You start with he easier steps first.

Both a truck and a car have nominally the same sub-sytems for detecting surrounding obstacles, just with different coverage. They have nominally identical collision-avoidance needs, except that a truck wouldn't have to be tuned to keep anyone on-board alive. This increases a truck's control parameter envelope in which to operate, lessening its requirements, making the problem one of only avoiding collisions without upsetting the vehicle or losing control.

A car, on the other hand, would still have a control parameter envelope of operation, but one that is severely limited in options because it cannot take more aggressive maneuvers that a passenger-less vehicle would be 'allowed' to take.

Do the passenger-less trucks first. (There is more money there anyway.) After thatm, maybe move on up to cars carrying passengers, taking all of your control parameter envelope lessons from the trucks with you, and adding-in the additional set of constraints (live people).

What is 'green hydrogen?' Is it different from regular hydrogen?

A: Hydrogen is hydrogen, and you can't tell what it was produced from by inspection.

Isn't Jet A basically the same thing as kerosene?

Yes, you are correct.

Their first planes will burn conventional jat fuel, just like any other jet.

If their planes can easily be retrofitted to burn hydrogen instead, then why can't everybody else's?

They still have RebBox DVD-vending machines?

Whatever happened to Usenet?

And you Slashdotters of old will remember what I had to say back then:

Nothining at all. I was unaware.

The blight of HP and their "Vending machines for Ink" should end.

As a consumer, you are putting a noose around your neck (read: wallet) if you purchase one of their "vending machines of ink," as their CEO called them.

Buy Canon instead. If you want to print,, at least, they are the least worst of the lot.

After you refuse to tip the machine, it turns up the volume (so you can hear it), and says:

"So, with food, tax, and A TIP OF ZERO PERCENT, your order comes to $XXX. Have a wonderful day!"

But I want new calculus!

NOW OUT AT YOUR NEAREST STORE!

The calculus, but written on vellum, not that old-fashioned stick-and-sand BS, and way better than chalk on slate!

I hate seeing posts like this (mine), but:

True. So true. Pearson is a dinosaur protecting one of its last threads convincing people to 'buy the course textbook.'

Didn't Pythagoras (or many others of his ilk) just use a stick to draw in the sand to teach the material? Thank goodness he didn't manage to copyright those things in perpetuity, or humankind would have never advanced beyond, well, writing lessons with sticks in the sand.