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ありがとうイラン！高市はいらん！ #高市やめろ

The tweet about aliens 2,000 light years away seeing the Roman Empire is wrong, and the actual physics is stranger. To see one person on Earth from that distance, you'd need a telescope wider than the distance from the Sun to Pluto. That's 50 times farther than Earth is from the Sun. No civilization can build that, ours or theirs. It sounds like exaggeration, but the math requires it. By the time light from a person on Earth reaches a planet 2,000 light years away, it has spread across so much empty space that catching enough to form an image would need that solar-system-sized lens. The geometry doesn't bend, no matter how clever the engineering. A SETI Institute team led by Sofia Sheikh worked all of this out in February 2025. Our loudest signal is planetary radar, the focused radio beams scientists fire at asteroids and planets to map them. Beams from the now-collapsed Arecibo dish in Puerto Rico could reach 12,000 light years away, about a tenth of the way across the galaxy. After that comes radar leaking from airports and military bases. A giant ground antenna like the Green Bank dish in West Virginia could detect those signals from around 200 light years out, roughly the distance to a few thousand of our nearest stars. A next-gen NASA telescope still in development could spot air pollution like nitrogen dioxide from factories and cars at 5.7 light years away. That puts Proxima Centauri, our nearest star at 4.2 light years, just inside the range. City lights at night go dark past the icy outer shell of our solar system, around 2,300 times the Earth-Sun distance. The famous "I Love Lucy" idea is also wrong. The story goes that aliens are watching our 1950s sitcoms because the broadcasts are still spreading through space. Astronomer Seth Shostak crunched the numbers years ago. A radio antenna the size of a city, sitting 55 light years away, couldn't pick that signal up. Not even close. At that range, the broadcast is a million times weaker than what the antenna can pick out of the background noise. Old TV signals fade out within the first light year of travel. So at 2,000 light years away, an alien civilization with our level of technology would see Earth as a tiny dot of light next to the Sun, with hints of oxygen, methane, and maybe some industrial pollution in its atmosphere. They'd see weather. They might guess that something living is here from the chemistry. Continents, cities, individual humans, the Roman Empire, single events: none of those would be visible. The information was lost within a few light years of leaving Earth, well before reaching the closest star. We're loud to anyone within 200 light years. Past that, we go silent. That signal bubble has only existed for 75 years, so the actual sphere of civilizations that could know we exist is small. And it's getting smaller. Television broadcasts are dying. Satellites use tight focused beams aimed at receivers on the ground, not the sky. Earth's window of being a noisy planet may already be closing.

4月29日(祝・水)フレンズチホー44(浅草フレチ)でのお品書きです！新刊のホ(ホ合同)等京都とラインナップ変わりませんがセール品も…？ ＋α何かあるかもしれません〜！よろしくお願いします❄️🦊✨

生成AI製ポスターほど萎える物はない… コレやられたら、行く気を失くしてしまう…