Tag Archives: SAS

Seattle Astronomy Calendar, week of April 13

A visiting author is the highlight of the week’s astronomy events, and the Moon will be involved in two interesting observing opportunities in the next seven days.

Does general relativity baffle you? Dr. Jeffrey Bennett says you’ll come away with a grasp of the concept if you attend his talk at Wednesday’s meeting of the Seattle Astronomical Society. Bennett is the author of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014.) The meeting begins at 7:30 p.m. April 15 in room A102 of the Physics/Astronomy Building on the University of Washington campus in Seattle. Check our preview article from last week for more about Bennett and the talk.

More talks

Theodor Jacobsen ObservatoryAlso on Wednesday the UW hosts one of its bimonthly open houses at the Theodor Jacobsen Observatory. Tom Esser, a senior in the Aeronautics and Astronautics Program at the university, will give a talk titled, “The Solar System: Planets, Spacecraft, and Rockets!” It will be a jaunt through the solar system, covering the spacecraft we have sent to the planets and some of their moons, and the rockets we used to get them there. Weather permitting, visitors will be able to get a look through the observatory’s vintage telescope, operated by volunteers from the Seattle Astronomical Society. Reservations for the talk are highly recommended, as the classroom where they’re held is relatively small. The events get under way at 8 p.m. April 15 at the observatory.

Another UW student will give a talk Thursday at Town Hall Seattle. Paige Northway, a student in UW’s Earth and Space Sciences Department, looks at magnetic field measurements in space, and the critical work played by magnetometers on small satellites. Her talk begins at 6 p.m. April 16 at Town Hall. It’s part of the UW Science Now lecture series.

Observing

The Moon will be part of some interesting celestial sights this week. On Wednesday evening Neptune will be easy to find, just four degrees south of the Moon. You’ll need a telescope to spot the most distant planet. At dusk Sunday a super-thin crescent Moon bunches up with Mars and Mercury low in the western sky. Mars and Mercury are drawing closer together; they’ll be just 1.3 degrees apart by April 22.

Check This Week’s Sky at a Glance, from Sky & Telescope magazine, for other observing highlights for the week.

Yuri’s Night

LogoYurisNight_WHITEring_TRANSPARENTbackground250x250Yuri’s Night, marking the 54th anniversary of Yuri Gagarin becoming the first human in space, was last Sunday, but the celebration rolls on at Pearson Air Museum in Vancouver, Washington, which will hold a Yuri’s Night World Space Party Saturday, April 18, beginning at 5 p.m.

Bennett talk Wednesday at SAS: general relativity made easy

Dr. Jeffrey Bennett says you don’t have to have the brain of an Einstein to understand general relativity.

“If you want to deal with all the mathematics of it then it is pretty complex,” Bennett says, “but if you want to just understand it on a conceptual level, it’s not that difficult to get a general grasp of it.”

Bennett, the author of of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014), will talk about the book, and relativity, at next week’s meeting of the Seattle Astronomical Society. The meeting, which is free and open to the public, begins at 7:30 p.m. Wednesday, April 15, in room A102 of the Physics/Astronomy Building on the campus of the University of Washington in Seattle. There’s still time to pick up the book, by clicking the link above or the cover to the left, before the talk.

Seattle Astronomy spoke earlier this week with Bennett, an adjunct research associate with the Center for Astrophysics and Space Astronomy at the University of Colorado. He says his Relativity Tour is a bit of an accident of timing. He’d been thinking about writing a book about relativity for several years. When the book came out last year it was just in time for the centennial of Einstein’s breakthrough, and Bennett decided to do his part for the International Year of Light and help the general public understand general relativity and how it makes so many everyday things possible.

Einstein was right

While Einstein proposed general relativity one hundred years ago, Bennett notes that many people still think of it as new physics, and others still strive to prove Einstein was wrong, but Bennett says that’s not going to happen.

“You can’t do that because it has checked out so much; you can’t make the evidence where it does check out go away,” Bennett explains. “In the same way, Einstein didn’t show Newton to be wrong. What you’re really looking for is to see if we can find a place where Einstein’s theory is not yet complete, and we need something else to take us to that next level.”

A good example of such a place is trying to find agreement between general relativity and quantum physics.

“That’s the known hole in our current understanding,” Bennett says. “Even though both work extremely well in the regimes in which they’ve been tested, they don’t quite meet up, and therefore there must be something else that we have not yet figured out that brings them together.”

Relativity for all audiences

Dr. Jeffrey Bennett

Dr. Jeffrey Bennett

Bennett, a recipient of the American Institute of Physics Science Communication Award in 2013, speaks to a wide variety of audiences, from adults down to elementary school kids, and has written children’s books as well as college texts.

“The commonality across all of the work that I do is that it’s all aimed at people who are not really very familiar with science and math, and in some cases, with the older audiences, maybe thinking they’re sort of afraid of these topics,” he says. “I’m always dealing on that introductory level—what science is and why you should care about it. When you’re dealing with it at that level, it’s not really that different to deal with children or with grownups, because either way you’re dealing with the same lack of knowledge and lack of understanding.”

Bennett recommends the talk he will do Wednesday for people from middle school on up, though he says younger kids often understand it as well.

“Come with an open mind,” he urges. “Even if you think this is something that you can’t understand, I think you’ll find you actually can, so I hope people will come in that spirit.”

More reading

Seattle Astronomy calendar, week of March 30

This week includes a total lunar eclipse, the beginning of Global Astronomy Month, and the return of popular open houses at the University of Washington’s Theodor Jacobsen Observatory.

Lunar eclipse

The shortest lunar eclipse of the century—just five minutes long!—will be an event for extreme night owls or early birds in the wee small hours of Saturday morning. Here in Pacific Daylight Time the partial umbral eclipse will begin at 3:16 a.m. April 4, totality lasts from 4:58 a.m. until 5:03, and the partial umbral eclipse will end at 6:45 in the morning.

The eclipse is so short because the Moon skims through out on the very edge of the Earth’s umbra—the shadow it casts when it passes between the Sun and the Moon.

Read all you need to know about the eclipse at Earth Sky Science.

TJO open houses resume

Theodor Jacobsen Observatory

The Theodor Jacobsen Observatory is the second oldest building on the campus of the University of Washington in Seattle. Twice-monthly open houses at the observatory resume April 1. Photo: Greg Scheiderer.

Bimonthly open houses at the Theodor Jacobsen Observatory at the University of Washington resume this week. The open houses are held the first and third Wednesdays of each month from April through October. Each event includes a free lecture and, if weather permits, viewing through the observatory’s telescope, operated by volunteers from the Seattle Astronomical Society.

The year’s first session will be held at the observatory beginning at 8 p.m. April 1. Dr. Ana Larson will give a kid-oriented presentation called Toys in Space; they’ll play with toys, testing and experimenting with them, and then predict how the same toys would work in space. Adults must be accompanied by someone 16 years or younger, for the first talk, though they’ll repeat it at 9 p.m. for adults.

Reservations are strongly recommended; the classroom is relatively small and can fill up fast.

Global Astronomy Month

awblogoApril is Global Astronomy Month, an annual effort by Astronomers Without Borders to bring astronomy enthusiasts from around the globe together to celebrate the organization’s motto: One People, One Sky.

The month’s activities culminate in a global star party on Astronomy Day, April 25. Check the website for events near you.

General relativity explained

Cool news from the Seattle Astronomical Society, which just announced that the program for its April meeting will be a talk by Dr. Jeffrey Bennett, author of What Is Relativity?: An Intuitive Introduction to Einstein’s Ideas, and Why They Matter (Columbia University Press, 2014).

Bennett has spent much of the last 30 years at the University of Colorado, where he remains an adjunct research associate with the Center for Astrophysics and Space Astronomy. These days he is mainly a writer and he has embarked on a “Relativity Tour” this year, celebrating the centennial of Einstein’s revolutionary ideas. Bennett’s basic premise is that general relativity is not all that difficult to grasp, and his goal is to bring relativity out of the realm of obscure science and help us understand it and the impact it has on our lives.

Oddly enough, it appears that my cats understand relativity. Followers of the Seattle Astronomy Facebook page recently saw the photo below of their demonstration. People trying to help others understand general relativity often ask them to imagine a bowling ball on a bed sheet. In this case Archie and Theodolinda used themselves as the massive objects, and the down comforter represents space-time. The green object in the background may be Neptune.

relativitycatsBennett’s explanation may not be simple enough for cats to understand, but it is advertised as suitable for anyone from middle school on up. Bennett has taught young kids, and in addition to scholarly textbooks and science tomes for adults, he has written a series of children’s books featuring the outer space adventures of Max the dog. To gear up in advance of the talk pick up What Is Relativity? by clicking this link or the photo above. Links to Bennett’s other books are below.

The Seattle Astronomical Society talk will be at 7:30 p.m. Wednesday, April 15 in room A102 in the Physics/Astronomy Building at the University of Washington in Seattle. In addition to SAS, the Relativity Tour is sponsored by Big Kid Science, Columbia University Press, Fiske Planetarium, and Story Time From Space.

More materials

Jeffrey Bennett website

Books by Bennett

Comet hunter Machholz to keynote annual Seattle Astronomical Society banquet

Don Machholz

Comet hunter Don Machholz will keynote the Seattle Astronomical Society annual banquet Jan. 24.

The Seattle Astronomical Society always seems to score interesting speakers for its annual banquet, and this year is no exception. Renowned comet hunter Don Machholz will give the keynote talk at the 2015 banquet Saturday, January 24, at the Swedish Club, 1920 Dexter Avenue North in Seattle.

Machholz is a prolific comet finder; he has eleven comet discoveries listed to his credit. The first was Machholz 1978L, discovered in September of that year after more than 1,700 hours of observing. The most recent was comet C 2010 F4 (Machholz). All of his discoveries have been made visually, quite a record in these days of digital cameras, computers, and space telescopes joining in the hunt.

Machholz is also considered to be one of the creators of the Messier marathon, an challenge to astronomers to observe all 110 objects in Charles Messier’s catalog in one night. Machholz has written a guidebook, The Observing Guide to the Messier Marathon: A Handbook and Atlas, published by Cambridge University Press in 2002.

Machholz has written several other books. Decade of Comets chronicles the comets discovered visually between 1975 and 1984. An Observer’s Guide to Comet Hale-Bopp came out in 1996.

It should be a most interesting evening.

Tickets to the banquet have been available for members of the Seattle Astronomical Society for several weeks, and went on sale to the general public today. The cost is $40 for members, and $50 for non-members. But why not sign up? Membership is just $35 annually. The Jan. 24 event will begin with a happy hour at 5 p.m., followed by a buffet dinner at 6 p.m. and the program at 7 p.m.

Further reading:

Don Machholz website

Spotting black holes

Black holes remain among the more mysterious objects in the universe. Though John Michell and Pierre-Simon LaPlace first posited their existence back in the 18th century, nobody has ever actually seen a black hole. Dr. Sean O’Neill, visiting assistant professor in the Department of Physics at Pacific Lutheran University in Tacoma, attempted to shed some light on these objects that don’t emit any during a talk at this month’s meeting of the Seattle Astronomical Society.

Steve O'Neill

Dr. Steve O’Neill of PLU spoke about black holes at the December meeting of the Seattle Astronomical Society. Photo: Greg Scheiderer.

O’Neill’s talk was titled “If We Can’t See Black Holes, How Do We Know They Exist?” His answer to the question boiled down to the notion that scientists have not yet come up with any other plausible explanation for some of the phenomena that they have seen.

The professor noted that traditional methods of observing astronomical objects simply are not practical for viewing black holes.

It would not work to send a spacecraft for a look. O’Neill pointed out that the nearest likely black hole is some 1,300 light years away from Earth. It would take a craft like Voyager about 25 million years to get there, and then, even if it arrived with its power source and transmitter intact, you would still have to wait 1,300 years to receive any messages about its findings.

“Traveling there is a terrible option,” O’Neill understated. “The direct visit option is bad even for things in the outer solar system, let alone things outside of our solar system.”

Imaging is also well nigh impossible, O’Neill said, and not just because a black hole, by definition, does not emit any light. Black holes, though incredibly massive, are also dense and quite small. Today’s telescopes don’t offer adequate resolution for a visual or photographic look; it would take a scope about ten thousand times the size of Hubble to spot the supermassive black hole at the center of the Milky Way.

Other methods offer some hope. O’Neill says we might well be able to spot the gravitational effects of a black hole, especially one circling another or dancing gravitationally with another massive object. In such cases general relativity predicts gravitational waves in space-time, and these might be observed directly. The approach is to use laser interferometry to detect changes in light wavelength. O’Neill says it’s a complicated process from which it is difficult to separate observational noise.

“In practice, there have been no detections of this phenomenon happening yet, even though most people think it probably does happen,” O’Neill said.

O’Neill says gravitational lensing also holds some promise, especially as observing equipment gets better.

“It’s tough to pick out the individual little black holes, though,” he said, noting that the method is used to look at distant, large, massive objects that lens other distant objects.

Though we haven’t yet seen a black hole, there’s plenty of evidence that infers that they exist. O’Neill shared data from observations of stars orbiting the center of our galaxy, seen in the infrared to cut through the dust blocking our direct visual view. Using Newton’s laws on the data from a number of years to reconstruct the orbits of the stars suggests they’re going around something that is about 3.7 million times more massive than our Sun. Whatever it is, we can’t see it because it doesn’t emit any light of its own.

“It’s tough to come up with a good alternative of what this could be,” O’Neill said. “It’s tough to imagine that gravity just goes wrong at this one point, for some reason, at the center of our galaxy.”

“That’s where we get a lot of direct evidence for what we think is the black hole at the center of our own Milky Way,” he concluded.

Looking at other objects leads to similar conclusions. Cygnus X-1 is a huge source of x-rays that is pulling material from a donor star nearby. The material holds a great deal of potential energy because of the high gravity of the system.

“All of that energy has to be converted into some form,” O’Neill explained. “Some of it is certainly kinetic, because stuff will speed up, but some of it is also going to be thermal energy. It will hit other little particles of gas, all of this will heat up to the point that it starts emitting x-rays, and that’s the stuff that we think we can see.”

One of O’Neill’s research interests is computer modeling of the jets of material often spotted shooting out of the centers of galaxies, such as Centaurus A. He shared a number of these simulations, in which material plummets toward a presumed black hole, doesn’t quite fall in, and then shoots away at great velocity. The models can be rotated to simulate views from various angles and compare the results to actual observations. While it’s an active area of research, O’Neill says most scientists are on the same page with their thinking.

“The reigning theoretical model for these jets by far—there’s essentially no viable alternative—is that fundamentally they’re powered by black hole gravity at the source,” he said.

While O’Neill notes that computer simulations like the ones he creates are way cheaper than observing, he expects that actual observations of gravitational waves from merging black holes are not far off. He also thinks that high-resolution x-ray and radio observations will allow us to see the disks of material around black holes within his lifetime.

Celebrating 10 years at Saturn

The Cassini spacecraft went into orbit around Saturn ten years ago, on July 1, 2004 in universal time. Ron Hobbs, a solar system ambassador of the NASA Jet Propulsion Lab, says some of the mission’s most exciting science has occurred quite recently.

10 years at SaturnHobbs spoke at the most recent meeting of the Seattle Astronomical Society about Cassini’s decade at Saturn, and notes that recent measurements of the gravitational field of the moon Enceladus have yielded some interesting findings.

“We are very confident that there is body of liquid water at the south pole that extends at least to 50 degrees south latitude on Enceladus,” Hobbs says. “There’s a body of water that’s in contact with rock. We know that some of the ice particles that get shot out into the E-ring have salt and organics in them. This has become on a very short list of places in our own solar system where we might find life.”

Mars and Jupiter’s moon Europa are two others on what Hobbs calls the “astrobiological short list.” Many scientists believe that life on Earth may have originated in hydrothermal ocean vents—a safe haven during the heavy bombardment era—and so it’s reasonable to suspect that life might thrive in similar environments elsewhere in the solar system.

Hobbs calls Cassini “the largest, most complex, and capable spacecraft ever built” and notes that we may owe its existence to persistent Europeans. There was some talk in the mid-’90s that Congress would scrap the mission before it got off the ground because of budget concerns. But the Europeans had already built the Huygens probe that hitched a ride on Cassini in order to do a study of the atmosphere of the moon Titan. Hobbs says word is that protests about the proposed cuts made it all the way to the vice president.

“The fact that we have Cassini, as far as I’m concerned, is in large part due to the fact that the Europeans had the guts to talk to the U.S. government and say, ‘You don’t renege on your promises,'” Hobbs says.

Like the Mars rover missions, Cassini has far exceeded the time allotted for its original scientific mission.

“The plan for Cassini when it arrived in July of 2004 was to study Saturn for four years,” Hobbs notes. “Cassini is still one of the healthiest spacecraft we have anywhere in the solar system. All of its instruments are working great, it’s got fuel.” Nonetheless, Hobbs says he occasionally hears talk that Congress again is considering pulling the plug on the mission. He says that would be a bad idea, as we still have a lot to learn.

The NASA video below gives a preview of the work they’re planning for Cassini over the next four years.