Famed British physicist Stephen Hawking has long wanted to go into space, so what better way to celebrate his 75th birthday than sending him a greeting from near-space?

The greeting comes courtesy of a stratospheric balloon experiment, executed at the Idaho-Oregon border by an Boise-based amateur science group called Near Space Education and Research, or NEAR.

The balloon-borne platform was festooned with a “Happy Birthday, Stephen Hawking,” plus a couple of party balloons for the occasion. (The heavy lifting was done by a much bigger balloon that’s out of the frame in NEAR’s video view.)

The platform made it to 92,051 feet before the big balloon popped and the platform fell back to Earth for recovery. That altitude is nowhere near the internationally accepted boundary of outer space, which is 100 kilometers (328,084 feet). But it’s high enough to provide a dandy view of the curving Earth below and the black sky above.

Here’s how NEAR’s L. Paul Verhage explained the chain of events in an email to GeekWire:

“At the altitude our balloon bursts, the air pressure is 98 percent vacuum. Also, the distance to the horizon is 372 miles. The launch took place on the border of Idaho and Oregon, so the video is showing parts of Nevada, California, Washington and Utah along with most of Idaho and Oregon. “During the video, you’ll see that the party balloons expand because of the reduced air pressure at altitude. As chemistry and physics students will recall, this is a result of Boyle’s Law (1660). “Robert Boyle’s work influenced Isaac Newton, and it turns out Stephen Hawking and Isaac Newton held the same chair at Trinity College (the Lucasian Professor of Mathematics).”

In a follow-up email, Verhage said November’s balloon flight cost just $150 in materials (and also made clear that the balloon was filled with hydrogen, not helium):

“The cost was $75 for hydrogen, and another $75 for a 1,500-gram weather balloon. “The balloon is tracked using amateur radio, using a tracking system called automatic packet reporting system (APRS). The balloon flew about 50 miles and landed south of Boise. It’s a desert out there, so recovery was pretty easy. In some flights, we’re close enough to see the parachute land. “On this flight, I also sent an experiment to test imaging in near infrared and thermal infrared. You can see the images on my website.”

Stephen Hawking turns 75 on Sunday, which is quite a feat for someone who was expected to die young due to his struggle with neurodegenerative disease. I have a feeling he’d be tickled by the tribute – just as I’m tickled by the roundabout reference to Boyle’s Law.

P.S.: The Daily Mail reports that Hawking saw “Rogue One” with friends during an early birthday outing this week, but you could argue that the biggest celebration will come in July, when an international conference on gravity and black holes will bring big-name physicists to Cambridge for a belated-birthday get-together in Hawking’s honor.