Dear Friends,
Lots of news in astronomy, so it’s time for one of my occasional updates. But before I begin, I’d like to invite those of you in the Denver area to come to my official “launch” of Max Goes to Mars, this Wednesday at the Denver Museum of Nature and Science:
Date: Wednesday, October 19, which is a museum “free” day and a day off for Denver schools.
Place: Denver Museum of Nature and Science, Ricketson Auditorium
Times: “Interactive readings” at 2:30 and 4:00 pm, book signings at Gift Shop before, after, and in-between.
Cost: FREE, both for museum entrance and for the talks. Details at
Fyi: You can also catch me briefly on Channel 9 news the same day, at about 12:20pm.
In other parts of the country, you can mark your calendars for my talks in Jackson, MS on Nov. 15 and at the Jefferson Science Lab in Newport News, VA on Feb. 21. Math professors can also look for me at AMATYC in San Diego, on Nov. 11.
And now for the news, this time covering:
1. Halloween Mars: Don’t Miss It!
2. Gamma Ray Burst Mystery Solved?
3. Get Ready for Pluto: New Horizons launch in January.
4. 100 Years of E = mc².
5. Op-ed: NASA’s New Moon Shot – Where’s the Inspiration?
1. Halloween Mars
Mars comes closest in its orbit to Earth, and hence reaches a peak in brightness in our sky, about every 26 months. That time is coming up right around Halloween, so it will be especially easy to spot when you are out trick-or-treating. In fact, you can already see Mars quite easily. Mars is rising in the southeast not too long after it gets dark, reaching its highest point to the south (on the meridian) near midnight, and then setting in the southwest. It’s bright and red-orange in color, so you can’t miss it. For more details, see http://science.nasa.gov/headlines/y2005/22sep_doublemars.htm.
Questions to ask in class:
*Why does this unusually bright Mars reach its highest point in the sky around midnight? (Answer: For Mars to be at its closest to Earth, it must be on the direct opposite side of Earth from the Sun [called “opposition”], so it is 180° away from the Sun in our sky, which puts it on the meridian at midnight.)
*Mars is also now in the middle of what is called its “retrograde loop.” What is this, and why is Mars in the middle of the loop now? (Answer: If you don’t already understand this, try the demonstration that is shown at the end of Max Goes to Mars or in my astronomy text, chapter 2. You’ll see that opposition always occurs in the middle of the retrograde loop.)
*Why are spacecraft to Mars launched about 26 months apart, and what mission was launched most recently? (The “launch windows” must be timed for when Mars is coming closest to Earth, which as above is every 26 months. The Mars Reconnaissance Orbiter was launched on August 12 and is currently en route to Mars; read about it at http://marsprogram.jpl.nasa.gov/mro.)
2. Gamma Ray Burst Mystery Solved?
Gamma ray bursts may be the most powerful explosions that ever occur in the cosmos, but until recently we had little idea of their origin. In fact, I chose them as Mystery #5 in On the Cosmic Horizon, my book on the top 10 mysteries in astronomy. Part of the mystery seemed to be solved a couple years ago, as strong evidence pointed to explosions of very massive stars – sometimes called hypernovae to distinguish them from other supernovae – as their sources. However, gamma ray bursts come in two distinct types, and the second type, “short” burst that last just seconds, still had no known source. Well, you may have read recent news reports claiming that the mystery is now solved, and that the sources of the short bursts are exotic collisions between two neutron stars or a neutron star and a black hole. So can we cross this mystery off the list?
Not so fast…Unless I’m missing something in the new results, here’s the thought process: To date, scientists have thought of only two viable ideas about how gamma ray might be produced: the hypernovae and the collisions of neutron stars or black holes. The new results rule out hypernovae for the short bursts so, voila, we’re left with collisions as the mechanism. It sounds reasonable, but one of the great lessons of astronomy in the past century has been that we should never underestimate the capacity of nature to think of something before we do. Just because we have ruled out the hypernovae does not mean we can automatically rule in the collisions. The mystery MIGHT be solved, but we’ll need a lot more data before I’ll scratch it off my list…
*Class project: The two missions that are giving us the greatest insight into gamma ray bursts at the moment are called Swift (http://www.swift.psu.edu) and HETE (http://space.mit.edu/HETE) . Go to their web sites to learn more about the missions, about gamma ray bursts, and about the current status of the attempt to unravel the mystery.
3. Get Ready for Pluto: New Horizons launch in January
Pluto may recently have been demoted from the ninth to the tenth spot in size for objects orbiting the Sun, but it’s still a fascinating place that we’d like to learn a lot more about. The first spacecraft to Pluto is now just about ready for launch: the New Horizons mission, developed by Alan Stern and other colleagues here in Boulder, is scheduled for launch from the Kennedy Space Center on January 11. It will then take about a decade to reach Pluto. Read about this exciting mission at
Questions for class:
*How many planets are there in our solar system? (Answer: trick question! The answer is unclear, especially since July’s announcement of “Planet X”; see my prior posting from Aug. 9.)
*What is Pluto made of, and how does it resemble a comet? (Answer: rock and ice; it’s composition is nearly identical to that of many comets, and it differs primarily in being unusually large for a comet.)
*Go to the New Horizons web site and learn more about the mission. When will it reach Pluto? What other objects will it visit? What are its scientific goals?
4. 100 Years of E = mc²
Einstein published his famous equation in September 1905, which means we’ve now known it for a century. Few equations have had such a direct and obvious impact on world history. It explains how the Sun generates energy, and has led to the nuclear age. Physicist Brian Green, author of The Fabric of the Cosmos (highly recommended!), wrote a great article about the famous equation for the New York Times op-ed page, Friday, Sept. 30, 2005. The link is http://select.nytimes.com/gst/abstract.html?res=F70F13FD38540C738FDDA00894DD404482, though it’s only free if you are a subscriber. (Users of my textbooks can also get access through the Research Navigator on the text web site.) And if you really want to understand Einstein’s theory and the equation, read Chapter S2 in the full version of The Cosmic Perspective.
5. Op-ed: NASA’s New Moon Shot – Where’s the Inspiration?
If you’ve read my children’s books or my op-ed from the Denver Post (archived above), you might think I’d be jumping up and down at NASA’s newly announced plans to return to the Moon in 13 years. I have not studied the plan in any detail, so I’m reacting mainly to newspaper accounts, but here’s my initial reaction: While it looks like a technically sound and relatively inexpensive way of returning to the Moon, it seems to be missing the key ingredient of INSPIRATION. Where’s the base with people from all nations, so that children around the world can look up at the Moon and say “people just like me are there right now, and if we can work together up there, surely we can work together down here too.” Where’s the great observatories that will make astounding new discoveries? Where’s the University of the Moon, to which children from around the world will work for admission? How will ordinary people get there, so they can share the experience of seeing our world as a “pale blue dot”? The plan simply says we’ll get there, and worry about the other stuff later. Moreover, the fact that is an almost entirely American plan, rather than an international plan, undercuts the critical importance of space exploration as a global endeavor. As is already evident from the many newspaper editorials saying “been there, done that,” the new plan sounds too much like what we did more than 36 years ago. I’m glad to see some type of plan, but this one is going to need a lot of work before it will convince anyone that it is worth the money it will cost.
6. Book update:
Max Goes to Mars: is now in bookstores everywhere. Special thanks to all of you who helped with my Max Goes to Schools donation program (https://www.jeffreybennett.com/donation.html), which has successfully placed the new book in more than 5,000 elementary schools across the country, and the first book (Max Goes to the Moon) in more than 3,000 schools. (Please note: EVERY public elementary school in Colorado should have received both books in the past week or two; if you know of a school that did not, please let me know.)
All for now!
Jeff