Readers discuss the hallucinatory effects of black holes on time and forbidden swimsuits.

“The extreme time dilation near the event horizon causes this seemingly paradoxical phenomenon,” says the theoretical physicist. Eduardo Martin-Martinez Research by the University of Waterloo in Canada. From the perspective of a distant observer, time appears to run more slowly near the edge of a black hole. As a result, falling matter appears to be frozen in time, never crossing the event horizon. Martin-Martinez The light emitted from that substance is stretched to longer and longer wavelengths, or redshifted, until it eventually becomes invisible.

“But from the perspective of the incoming matter itself, time is experienced normally.” Martin-Martinez It says that matter crosses the event horizon after a finite amount of time and moves to the singularity at the center of the black hole. “If a distant observer approaches the horizon, they will see the matter cross the horizon in a finite amount of time, and they will also cross the horizon in a finite amount of time themselves.” Martin-Martinez He says.

Speed ​​up

Elite athletes need perfect technique to reach the predicted top human speed in running or swimming. Erin Garcia de Jesus “Reported inWhat is the human speed limit?” (Serial Numbers: July 13, 2024 and July 27, 2024, p. 36).

In the 2000s, Speedo’s now-banned swimsuit line led a wave of new records in the 50m freestyle. Garcia de Jesus It was reported that the swimsuit compresses the swimmer’s body to increase buoyancy.

Compression tends to increase density, which decreases buoyancy, so the reader David H. Brand I asked how the lawsuit could have such an effect.

These are two parallel effects, and one does not lead to the other, the news editor says. Christopher Crockett. The compression made the swimmer’s body more streamlined, reducing drag. At the same time, the suit trapped air around the swimmer’s body, increasing buoyancy. croquette He says.