Astro 2201   Lect #2   Essay #5   Due date:   Wed Nov 4, 2009
You are back in Washington and still in your job as a scientifically-knowledgeable staff adviser to the influential Senator Wisdom.

In order to take some pressure off amidst the current budget deliberations, Senator Wisdom recently took a stroll to the nearest supermarket to get a refill of twinkies and, while waiting at the counter, read a tabloid's article claiming:

Russian Cosmonauts Travel to the Galactic Center
and Discover Giant Black Hole that Threatens to Destroy Earth
Looking old and haggard but otherwise well on their return from a journey in a nuclear-powered spacecraft launched in 1965 at the heyday of the Soviet space program, a trio of cosmonauts reported today that they witnessed the extraordinary vision of a giant black hole, located near the center of our Galaxy, consuming at a prodigious rate all matter surrounding it. Stars, planets and gas, previously seen harmoniously orbiting at large distances from the Galactic center, are now disappearing in a dark spot which continues to shrink in size. The Solar System is thought to be threatened, according to our reliable source. A famous Swiss astrophysicist from the Observatory of Basel, who prefers to remain anonymous, reports to our correspondent that Earth will be gobbled up in December 2012, unless "the appetite of the beast" is satiated by forcing its mass to exceed the so-called "Schwarzschild limit", beyond which the condensation ceases to be a black hole.



Having sworn in 1957 never to let the Russians get ahead again, the Senator is seriously disturbed by this report and wonders whether the situation calls for emergency legislation getting pushed through Congress. Ever the farsighted tactician, the Senator also foresees a possible opportunity for political gain, but is nonetheless concerned about maintaining a reputation of high scientific understanding. In past circumstances, an uncautious announcement by astronomers suggested that a small asteroid had a non-negligible chance of colliding with our planet, and thus of wreaking havoc to human civilization; the announcement was soon seized by folks associated with a defense research institute, who proposed to "nuke the sucker" before it collided with Earth. The whole thing turned out to be an exceedingly alarmistic episode: the asteroid went by 3 million miles from Earth and no nuclear missiles were ever deployed. Prompted by the new announcement, however, the Senator is considering the possibility of being the first to propose to "nuke" the threatening black hole.

Remembering that you listed your enrollment in Astronomy 2201 on your resume, the chief aide to the Senator has given you the unkind task of writing a short memo (less than 500 words) evaluating the veracity of the tabloid report. In it, you should explain that: (a) a black hole at the center of the Galaxy is of no immediate danger to Earth; (b) that a black hole does not behave like a vacuum cleaner; it does not "suck up" any matter orbiting it at a fair distance; (c) that "nuking the sucker" might not be a terribly good approach, even if the black hole were to pose a problem; (d) that the time scale forecast for Earth's demise makes no sense; (e) the article is of dubious merit from its statement of the facts. You may wish to preface the memo explaining to the Senator what a black hole is (and is not) and general concepts about relativity that are important and relevant.

Because of the word limit, you need to think carefully about how to address the five points (a-e above) succinctly; make an outline and stick to it. Since this is a memo to your boss (and not a piece of prose), you may, if you wish, use organizational tools such as bullets that help convey the information in a brief way. Be sure to cite rigorously any references from which you draw information, but be sure to use your own words! The Senator will not be impressed otherwise.