General science thread

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After a heart attack, the damaged parts of the heart tissue die and do not regenerate. Instead, the heart develops scar tissue that cannot transport electrical signals - essential for proper beats - like a healthy heart does. With scar tissue, a person typically suffers from heart failure and other deadly complications.

Biomedical engineers at Duke University developed a "heart patch" to cover and repair heart tissue damaged by heart attacks that's just as strong and active as real tissue.

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Retired Cmdr. David Fravor spent 18 years as a Navy pilot, but nothing prepared him for what he witnessed during a routine training mission on Nov. 14, 2004.

"I'm not crazy, haven't been drinking. It was — after 18 years of flying, I've seen pretty much about everything that I can see in that realm, and this was nothing close."

He recalled flying his F/A-18 fighter on a training mission on a beautiful Southern California day 13 years ago when things started to get strange.
Controllers on one of the Navy ships on the water below reported objects that were dropping out of the sky from 80,000 feet and going "straight back up," Fravor said.

"So we're thinking, OK, this is going to be interesting," he said.

As they were looking around for the object that appeared on the radar, another aviator spotted something. "I was like, 'Dude, do you see that?'" Fravor recalled saying.

“We look down, we see a white disturbance in the water, like something's under the surface, and the waves are breaking over, but we see next to it, and it's flying around, and it's this little white Tic Tac, and it's moving around — left, right, forward, back, just random," he said.
The object didn't display the rotor wash typical of a helicopter or jet wash from a plane, he said.
The planes flew lower to investigate the object, which started to mirror their movements before disappearing, Fravor said. "As we start to cut across, it rapidly accelerates, climbs past our altitude and disappears," Fravor recalled.

"When it started to near us, as we started to descend towards it coming up, it was flying in the elongated way, so it's [like] a Tic Tac, with the roundish end going in the forward direction ... I don't know what it is. I don't know what I saw. I just know it was really impressive, really fast, and I would like to fly it," he said.
The disturbance in the water also vanished with object, he remembered.
"So we turned around — we couldn't have been more than about a couple miles away — and there's no white water at all in the ocean," Fravor said. "It's just blue."
At that point, they decided to return to complete the training exercise when they were told the object or something similar reappeared.
"And the controller comes up and says, 'Sir, you're not going to believe this. That thing is at your half point,' which is our hold point," Fravor added. "And I'm like, 'Oh, great.'"
Another plane that launched from the aircraft carrier USS Nimitz around the same time had its radar jammed and was able to pick up the object on an infrared channel.

"He gets close enough to see a couple of objects come out of the bottom, and then all of a sudden it takes off and goes right off the side of the screen and, like, takes off," Fravor said.
He recalled that the speed of the object, which he said had no exhaust trail in infrared scanning, was stunning.