To spot a planet
Planetary peekaboo” (SN: 9/22/12, p. 26) says that to hunt for faraway planets, the Kepler spacecraft “watches for blinks occurring when a planet dims a star’s light by passing in front of it.” For a star to dim when a planet moves in front of it requires us to be in the same plane as the orbits of the remote planets. Evidently it’s expected that this is commonly true. Why is that?
Bryan Mumford, Santa Barbara, Calif.

That’s correct: To see a planet passing between Earth and its star, the system and Earth need to be aligned just right. Astronomers don’t expect this to be common. On the contrary, they’ve calculated that only about 1 percent of planets in an Earthlike orbit would be aligned to produce a transit. So, in general, spacecraft like Kepler can detect only a fraction of the planets that may be out there. Imagine how many more there could be. —Nadia Drake

Time to tweet
I read the Twitterverse article “Social media sway” (SN: 10/20/12, p. 22) with somewhat mixed feelings. While I am in no hurry to be connected, I recognize in the social media revolution a larger communication revolution that is maturing at a serendipitous time indeed. We can take it as given that global warming will wreak havoc with agriculture as we know it, which in terms of industry, markets and politics will really put the squeeze on our species globally. We are going to need the best possible means of discussing problems related to the survival of life on this planet in the course of the coming century.
Ron Elbert, Somerville, Mass.

Although you acknowledge that misinformation has played a role in many elections in this nation and has impacted political allegiances throughout history, the article implies that technology changes its significance. Our founding fathers said that an ignorant electorate will destroy our republican-type democracy. What I see is not a danger from technologic information dissemination, but the danger of indifference to facts or knowledge. Politics is about power, and power only. Everyone wants to be on the winning side.
Carolyn Lawson, online comment

Studying suicide
Perhaps the key to preventing abuse-related suicide “Suicidal threadsSN: 11/3/12, p. 20) lies in studying the experience of resilient, happy adults who have overcome a traumatic childhood. Why not start by interviewing any well-adjusted siblings who shared the victims’ childhood environment?
Barbara Fenner, via e-mail