[Q&A+] Earth from Mars, Asteroid Discoveries After Vera Rubin, Life in Mars Samples | Q&A 383
Could people on Mars see city lights on Earth? Will it still be possible for amateurs to discover asteroids after Vera Rubin? What can we expect from Mars samples? And in Q&A+, what happens if you put your hand across the event horizon of a black hole?
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Comments (12)
Very exciting Ms. Rubin!
why were you using chat gpt?
If I'm in very close orbit around a SMBC in the darkest part of the universe. No photon in the photon sphere. My orbital speed is already at 99.9999% of the speed of light. I push my hand towards the event horizon. At the exact point of the event horizon, time from the POV of an external observer stops. So I'd push my hand towards the event horizon, but I'd feel a resistance. An enourmous resistance. My hand wouldn't want to go through the horizon. The entire age of the universe would pass and my hand would still be at the very edge of the EH. Never going through.
Very creative thinking! I’m looking for writers for a project with science and stories to blow people’s minds. You’re invited!
I am sorry about the length of this Comment, but I wanted to make a timely response. I am writing this from my hospital bed, so please excuse the imperfections. In 1974, give or take a year, I attended a lecture by Carl Sagan at the University of Washington, Seattle. The subject of the talk was whether a Martian could detect life on earth. Using the technology we had on earth in the 1970s. The Martian astronomer finally concluded that there was life on earth. The life form was rectangular, With circular objects located near each corner.. What appeared to be parasites of the life form entered and departed from life form on a regular basis. The low point of the presentation was that the person operating the carousel projector dropped two of the slide trays. He tried in a valiant way To restore the order of the photos. Without success. Many of the images were upside down. Sagan concluded the presentation by noting that the slideshow presentation suggested that Life on earth had only limited intelligence. I felt so bad for the operator of the carousel projector. Warm regards from Finland. Chris Senn
A nice episode. Regarding finding evidence of Life on Mars, Hank Green says that there is a possibility we could tell if the handedness of the life matched with Earth or not. If it is different than the handiveness on Earth, it would be very strong evidence that it was an independent origin.
On the black hole across the event horizon question, even if you had the suit and a sufficiently massive black hole for a gradual gradient, there's a problem that occurs to me: your blood will continue to flow into your hand, but it will never be able to leave. And there's no way for the blood to clot, either. So in addition to all the other ways you would die, you would simply bleed out, even faster than if you had cut your hand off.
True. Your blood in your hand would have to move faster than speed of light to get back into your body. Nothing crosses that boundary more than once. But the rest of your body would have to be traveling almost at the speed of light just to stay on the outside of the event horizon. This in itself is almost impossible and too risky.
I'm not convinced by the argument that the hand inside the event horizon would have to move at the speed of light to escape. As a counter argument consider that the escape velocity from earth is E. A very long rope, dangling from a geostationary orbiting craft down to the surface of the earth, can be winched up slowly back to the craft without having to reach speeds anywhere near E. Why would this not work when escape velocity is c, across the event horizon of a supermassive black hole with no accretion disk?
yes it's counterintuitive. That's because c is a hard limit. it's not that you have to go faster than c exactly to get out, it's because at the event horizon, time and space exchange places. It's WTF weird, but know this: there is no coming back from that.
The black hole question and answer sounds exactly like one that was published previously?? Was it culled from an old live Q&A?
"I asked the Bullshit Machine that is based almost entirely off of stolen material and is making the environment more horrible" isn't something I hear and continue to care about whatever else that person has to say on anything ever.