Exploring the solar system with Emily Lakdawalla

Emily Lakdawalla gushes with enthusiasm about the cool things to see and learn in our solar system, and for her that would be reason enough to explore those places.

“I’m just curious,” she told the Rose City Astronomers at their most recent meeting in Portland. “I like to see the new places, I like to see the planets. I think it’s awfully fun, but that’s not a good reason to make somebody else pay for it.”

Emily Lakdawalla
(Isabel Lawrence/Planetary Society)

Lakdawalla, senior editor and planetary evangelist for the Planetary Society, said the public policy reasons for exploration are to answer the questions of how we got here and whether we’re alone in the universe. We need to find those answers off-planet.

“Earth is a wonderful planet to live on!” she said. “It’s my favorite planet; it’s temperate, it’s a very comfortable place to live. It’s also a terrible place to try to answer these questions from a planetary science point of view.”

That, she says, is because Earth is dynamic. Forces like weather and volcanism and even life and evolution change things and mess up the ancient evidence about how things were before. We need to go to space to find territory in a more undisturbed state.

After the first wave of planetary exploration, with Viking, Mariner, and the like, enthusiasm and political will and funding for planetary exploration waned. Lakdawalla explained that the Planetary Society was founded in 1980 to be an advocate for finding the answers. We’re now enjoying a second wave of exploration.

“Since the end of the second millennium, we’ve had this amazing expansion of robotic space explorers all over the solar system,” Lakdawalla said. She talked about many of them, with a particular emphasis on Mars. This is squarely within her bailiwick, as she is the author of the book The Design and Engineering of Curiosity: How the Mars Rover Performs Its Job (Springer Praxis Books, 2018).

She explained how a series of Mars missions followed the water. Mars Global Surveyor made a map. Mars Odyssey detected evidence of hydrogen by analyzing neutron movement, and hydrogen could mean water. Phoenix went to look for water and found ice. Mars Express found places where there’s clay, evidence of water, in many places. Curiosity went to one of those places.

“Curiosity has found environments on Mars that are unequivocally habitable,” Lakdawalla said. “Curiosity is not capable of looking for fossil evidence of microbial life on Mars. It doesn’t have the instruments.”

While Curiosity continues its mission, Lakdawalla said we’ve pretty well exhausted this particular line of research.

“We have found that, yes, Mars could have originated life in the past, but we can’t tell you if there was life there or not,” she said. That question will be up to the next line of rovers, such as the ESA’s ExoMars and NASA’s Mars 2020.

Lakdawalla spent some time on the outer solar system, particularly the life possibilities on the jovian moons Ganymede and Europa and Saturnian moons Titan and Enceladus. She noted that on Titan the temperature is such that methane could exist on the surface in liquid, gas, or solid forms, much as water can exist on Earth. The Huygens probe found round rocks on Titan, a significant discovery for a geologist.

“We have a river, except it’s a bizarro river,” Lakdawalla said. “Those rocks are made of water ice, and the river they were tumbled in was a methane river. It’s so familiar and so completely bizarre.” She said it’s hard to say if life could exist in that strange environment. Another reason for further exploration!

Lakdawalla said she’d love to see a mission soon to either Uranus or Neptune.

“They don’t get enough respect,” she said. “I think they’re awesome worlds.” But remembering her statement that coolness alone isn’t enough of a reason for the trip, she noted that the ice worlds are at an intermediate size between the gas giants and the terrestrial planets.

“Most of the exoplanets that we have discovered in the last 30 years have been of this size,” Lakdawalla noted. “We’ve never studied up-close the ones in our own solar system except for one Voyager 2 fly-by. We don’t understand these worlds very well at all, so how are we going to understand the rest of the universe and all of these other planets orbiting all of these other stars?”

Lakdawalla concluded that it’s a great time to be in the planetary exploration business.

“We’re doing it for a reason; we’re trying to understand how we got here, whether we’re the only life in the solar system,” she said. “It’s just a wonderful field of study.”

The expanding universe: discovery, controversies, and hope

We’ve known that there is a universe outside the Milky Way, and that it is expanding, for less than a century.

“Throughout the entire history of the universe, of knowing it’s expanding, there have been a tremendous number of controversies over it, and there’s still one that persists today,” said astrophysicist and author Ethan Siegel. Siegel, author of Beyond the Galaxy: How Humanity Looked Beyond Our Milky Way and Discovered the Entire Universe (World Scientific Publishing, 2015), spoke at last week’s meeting of the Rose City Astronomers in Portland, Oregon.

The controversy actually goes back to before the expansion was observed, to Albert Einstein. His equations describing general relativity suggested that gravity would collapse the universe onto itself, and as he believed the universe was static, he threw in a “cosmological constant” to push back against gravity. Einstein later called that his biggest blunder, though some wanted to let him off the hook for it when dark energy was proposed to do the exact same thing.

“I am here to tell you that this was Einstein’s reasoning and throwing this in there when he did was a super big blunder because the universe isn’t static,” Siegel said. Einstein should have trusted his theory, he said, and taken it to the next step.

The universe is expanding

By the 1920s Edwin Hubble observed a Cepheid variable star in the Andromeda “nebula” that indicated that it was far outside the Milky Way and a galaxy in its own right. Astronomers were also studying redshift as an indication for the speeds at which galaxies were receding from us. Siegel explained that through this, Hubble determined that the universe was expanding at a rate of 600km/sec/Mpc (kilometers per second per megaparsec.) This became the Hubble constant. But it wasn’t so constant.

Siegel noted that, knowing the size and expansion rate of the universe, you can figure its age by running the numbers in reverse and going back to the beginning, to the Big Bang. The resulting calculation determined that the universe was about two billion years old. Geologists at the time had already pegged the age of the Earth as at least four billion years.

“This was a problem for Hubble, because the universe isn’t allowed to be half the age of the Earth,” Siegel noted. “Either this expansion rate is wrong and this age for the universe is wrong, or the age of the Earth is wrong.”

It turns out that Hubble’s main mistake was in figuring that all variable stars are alike. Siegel said Walter Baade came along in the 1940s and discovered that they are not. Finding that most of the Cepheids Hubble had looked at were non-classical, they re-ran the numbers from Hubble’s data.

“As you accumulate more knowledge, as you accumulate a better understanding of what you’re actually looking at, you can go back and get more useful science out of this data,” Siegel said. This second look doubled the distance to these stars and reduced the value for the Hubble constant to 270km/sec/Mpc. This in turn put the age of the universe at five billion years.

“That’s better,” Siegel noted. “The universe is older than Earth. That’s one problem solved.”

Narrowing it down

Dr. Ethan Siegel, creator of the “Starts With a Bang” blog, gave
a talk about the age and size of the universe to the Rose City
Astronomers February 20. Photo: Greg Scheiderer.

As time went on astronomers developed the “distance ladder” for determining the vast distances in the universe. You first measured the distance to Cepheid variables within the Milky Way, then gauged the distances to other galaxies using Cepheids spotted there. Type 1a supernovae could be spotted really far out. As we learned more about the stars we got a little better at figuring distances.

Things got really interesting in the 1960s, according to Siegel. We discovered that we could determine the ages of stars by measuring their color and brightness. The Hertzsprung–Russell diagram told us that the oldest stars were between 14 billion and 16 billion years old, significantly older than the age of the universe determined by Baade. Astronomer Allan Sandage, who as a graduate student was an assistant to Hubble, came along and said you needed two things to make the universe that old: it had to be low enough in density to make a vast expansion, and the expansion rate had to be low.

Dueling Hubble constants

This, Siegel said, was where the controversy came in. Sandage said the expansion rate would have to be between 50-60km/sec/Mps. Rival astronomer Gérard de Vaucouleurs of France put it at around 100km/sec/Mpc. The race was on to make observations to see which group was right. Amazingly enough, each group’s observations matched up with what they thought the answer would be.

“This just goes to show that you cannot have the same people making the same measurements and trust them,” Siegel said. “This is why you need independent confirmation.”

It turns out Sandage and de Vaucouleurs were both wrong. There’s still no agreement on the right answer, but the disagreements are getting closer together. Sigel said the Hubble Space Telescope’s improvements in measuring the size of the universe return a value of 74±2km/sec/Mpc. The Planck mission’s observations of the cosmic microwave background radiation suggest 67±1km/sec/Mpc.

“There is a fight over the results like there always seems to be, because we are scientists and we cannot agree on anything,” Siegel said. “That is good, because questioning is what keeps us moving forward and what keeps us learning more.”

“The way we’re going to get there is with more and better data,” he added.

Better data

The better data will come from missions such as the European Space Agency’s Gaia, the James Webb Space Telescope, WFIRST, and the Large Synoptic Survey Telescope, which combined might improve our parallax measurements of cosmic distances by a factor of ten. We might also weed out faulty assumptions in the earlier work or get more accurate insights into the balance between matter and dark energy in the universe.

“If we can wait until the next decade, we might see that 74 number come down, we might also see the 67 number come up,” Siegel said. “The point is uncertainties are going to be reduced by more and better data.”

Siegel said that right now it’s pretty much agreed that the universe is about 13.8 billion years old and consists of about 30 percent matter and 70 percent dark energy. But the minuscule pluses or minuses can lead to huge fights.

“When that data comes in at last we will know exactly how fast our universe is expanding, how old it is, and what it all means for both our cosmic origins and our cosmic fate,” Siegel concluded. “That’s pretty good stuff.”

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In the podcast linked below Siegel covers much of the topic matter of this article and his talk. His new book, Treknology: The Science of Star Trek from Tricorders to Warp Drive (Voyageur Press, 2017), is scheduled for release in October.

Major changes in store at Goldendale Observatory

Big changes are in store at the Goldendale Observatory in Goldendale, Washington. The facility’s telescope, installed in 1973, has already been reconfigured and more improvements are planned. Most of the existing facility, save for the south dome that houses the telescope, will be demolished this winter and replaced with a bigger, more useful observatory that operators hope will be operational in time for the solar eclipse in August.

Troy Carpenter, interpretive specialist at
Goldendale Observatory State Park, spoke
at a recent Rose City Astronomers meeting
about plans for improvements at the
observatory. Photo: Greg Scheiderer.

Troy Carpenter, interpretive specialist at the observatory, talked about the plans at the recent meeting of the Rose City Astronomers in Portland. He said that up until recently the telescope and facility had been virtually unchanged since they opened.

The telescope, originally a 24.5-inch classical Cassegrain built by amateur astronomers from Vancouver, Washington, was reconfigured this summer.

“It is still the same telescope, but it has become a Newtonian,” Carpenter said. “The primary reason this was converted from Cassegrain to Newtonian is because, frankly, a classical Cassegrain telescope is totally inappropriate in Goldendale, Washington.”

The original scope, with an effective focal ratio of f/14.5, had a focal length of more than 9,000 millimeters. For telescopes and cameras, that’s extremely long.

“I would even say excessively long because it means the telescope can only operate at very high orders of magnification,” Carpenter said. That was bad, because the telescope couldn’t really look at large, dim objects like the Andromeda galaxy or Orion nebula. Also the scope required good seeing conditions, and while it’s dark and clear in Goldendale, the seeing at the observatory isn’t typically great. On top of that, the secondary mirror was eight inches wide with a ten-inch baffle that blocked too much light, leading to poor contrast at the eyepiece.

“In short, what we had was a horribly over-magnified image with terrible contrast all the time, and as a result this very impressive-looking telescope became kind of infamous, and not so much famous, for being awful,” Carpenter said. “All of these issues contributed to the decision to convert it to a Newtonian.”

That work, and some other adjustments to the telescope, its mount, and adjustability, were completed in September. Back to a more appropriate 3,050-millimeter focal length, Carpenter said views through the telescope are much better now. An improvement yet to come is replacement of the primary mirror, which has deteriorated over 43 years of use. In addition, the mirror is five inches thick, weighs 200 pounds, and takes four hours to reach thermal equilibrium, which is essential to good viewing.

A replacement is being fashioned by a company in Pennsylvania that has done work for NASA. The new mirror, computer designed and fabricated from inexpensive materials, will be the same width but just two inches thick and will weigh only 35 pounds. It will take just 15 minutes to cool to ambient temperature. They hope to have it in Goldendale and installed within the next few months. Its price tag, with a generous educational discount, is $25,000, and while that may sound like a lot, Carpenter noted a similar-sized mirror made of fused quartz might go for ten times as much, a quarter million.

New observatory

Big changes are in store for the buildings at Goldendale Observatory State Park, too.

Preliminary plans for the new facility
at Goldendale Observatory.

“We’re tearing it down so that a much larger facility can be built in its place,” Carpenter said. Everything except the south dome that houses the telescope will go. The new facility will include a large auditorium for classes and lectures that will seat about 150, interpretive exhibit space, and a rooftop observation deck. The total cost of the improvements, which are being made in several phases, is $5 million, which is being covered by capital funds appropriated by the Washington State Legislature. Demolition is set for this winter and they hope to be operational with the new facility in time for the total solar eclipse on August 21, 2017. While Goldendale won’t be within the path of totality as it was for the 1979 eclipse, the Sun will be about 98 percent obscured at the observatory that day, so it will still be something to look at.

One page detailing the planned improvements is above; you can see more of them in the latest newsletter from Friends of Goldendale Observatory.

Light pollution

While it’s pretty dark in Goldendale, many feel that light pollution has increased in town in recent years. Concerned folks this summer held a Gorge Night Sky Symposium to discuss the situation. (See our recap of the event.) Carpenter raised a few eyebrows in the room, mine included, with his take on the issue.

Goldendale Observatory. Everything but the dome on
the right will be demolished to make way for improved
facilities. Photo: Greg Scheiderer.

“I’m going to surprise you by not being the loudest opponent of the light pollution we have in Goldendale,” he said. He added that he grew up in New York and has lived in Philadelphia, so he knows light pollution.

“I’ve been to places where stars don’t exist,” he said. So while Goldendale has some light pollution, Carpenter noted that they still have great views of lots of faint fuzzies in the dark night sky.

“It’s low on my priority list because it’s a politically charged issue and it makes us very unpopular every time we bring it up,” Carpenter explained. “Our friends group, however, does care very much about light pollution and they do work hard.”

He noted that the town of Goldendale is working on an improved lighting code, and is converting to full cut-off, dimmable LED street light fixtures. Despite some light pollution, Carpenter said it’s still a great place for stargazing.

“You can see the Milky Way from horizon to horizon in Goldendale,” he said, “and that’s a wonderful thing.”

We look forward to a dark, clear future at Goldendale Observatory.

Gravitational wave discovery ushers in new era in astronomy

“This is beginning a new era in astronomy,” said Ethan Siegel about the publication in February of a paper announcing that scientists had detected gravitational waves. Siegel has taught physics and astronomy at Lewis & Clark College and the University of Portland in Portland, Oregon. He is creator of the science blog Starts With a Bang, and is the author of Beyond the Galaxy: How Humanity Looked Beyond Our Milky Way and Discovered the Entire Universe (World Scientific, 2015). Siegel gave a talk at this month’s meeting of the Rose City Astronomers in Portland about what he calls the discovery of a lifetime.

Ethan Siegel

“This was something, when it was first proposed, that was really taken to be a preposterous consequence of a theory and something that we never really thought we were going to be able to test,” Siegel said. “We have gone in 101 years from pure theory to concrete, direct detection of gravitational waves.”

Einstein’s theory of relativity states that mass and energy bend spacetime, and that’s why objects orbit each other. Relativity explained anomalies in the orbits of planets in our solar system, but Siegel said there is an “extra weird” effect because the orbits decay.

“Another consequence of Einstien’s relativity is that as things spiral in, and it takes a long time to do, but as they do they emit a special type of radiation; they emit radiation that goes through the fabric of space itself,” Siegel said. “This is gravitational radiation.”

It takes way too long for that to happen here in the solar system. For Earth’s orbit to decay completely and merge with the Sun would take 10¹⁵⁰ years, according to Siegel. He said we’ll have to look elsewhere to see the effects happen on human-length time scales.

“You need to find heavy masses; heavier mass in relativity means a stronger effect,” Siegel said. “You need them to have small distances, where small distance is a few kilometers, not a few million miles. And you need them to orbit at fast speeds, where fast is kind of close to the speed of light.”

Luckily these conditions exist. Black holes, neutron stars, and pulsars can do the trick; the gravitational waves detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO) last fall were generated by merging black holes. One of those black holes started out at 36 solar masses and the other at 29. After the merger they weighed in at 62 solar masses. That’s simple arithmetic: 36+29=65; what happened to the other three solar masses? Siegel said, oddly enough, this was a prediction by Einstein as well. It’s the flip side of e=mc².

“When these two black holes merged, three solar masses, about five percent of the total mass, was converted into pure energy,” he said. “That energy is the gravitational radiation and is why we here on Earth were able to detect this huge event of two black holes merging from over a billion light years away.”

Siegel is amazed that we were able to figure the mass, spin rate, merging speed, mass loss and other characteristics of these distant objects.

“We learned all of this information from one 20-millisecond signal that moved two laser arms by less than 10^-18 meters,” he marveled. “What I’d say we have now is a whole new way to discover our universe.”


That way is improving rapidly. The LIGO detectors at Hanford, Washington, and Livingston, Louisiana, are being tweaked to even greater sensitivity. New detectors are planned for Italy, Japan, and India. Siegel said the ultimate would be to build three huge LIGO detectors in space, forming an equilateral triangle in Earth’s orbit and having detector arms hundreds of millions of kilometers long.

“If you do that, you can not only watch things merge with supermassive black holes, you can find mergers of ultramassive black holes,” Siegel said. We might even be able to spot gravitational waves from cosmic inflation within the light of the cosmic microwave background. Siegel said if that happens, it would prove that gravity is a quantum force.

“There’s no way to make these fluctuations unless gravity is inherently a quantum force,” he explained. “The process that makes these fluctuations is a quantum process.”

Siegel said it’s a thrilling time to be involved in astronomy.

“This is the first time we’ve seen something astronomical without using a telescope or light of any type,” he said. “This is the dawn of astronomy beyond light-gathering telescopes.”

Astronomy reduced to pixel archive science

A University of Oregon professor of physics frets that astronomy is drowning in data that threatens to reduce it to a “pixel archive science.” His solution is something right out of Star Trek.

Dr. Gregory Bothun made a presentation titled, “Big Data, Discovery, and a New Kind of Astronomy: Are We Prepared?” at the February meeting of the Rose City Astronomers at the Oregon Museum of Science and Industry in Portland. Bothun noted that efforts such as the Sloan Digital Sky Survey provide the stuff of discovery.

Prof. Gregory Bothun of the University of
Oregon spoke about astronomy’s challenges
with big data to a meeting Feb. 15
of the Rose City Astronomers in Portland.
Photo: Greg Scheiderer.

“The great thing about surveys is that they produce a catalog of calibrated sources which serve the community on a worldwide basis and involve more people in astronomy,” he said, adding that, for this reason, surveys should come before more targeted observations of individual objects.

“We’ve done it the other way around, mostly because of some kind of fetish with large-aperture glass,” Bothun said. “We have spent far more money building large telescopes than we have on building real, useful surveys that serve the community.”

Bothun pointed out that sometimes a big telescope will do a survey, such as Hubble’s ultra-deep-field work, and this leads to tremendous advances.

“Every time an instrument does a calibrated survey, science moves forward much more rapidly than some individual working with some piece of aperture doing a follow-up observation,” Bothun said.

A pipeline problem

While Sloan was useful, Bothun said, it also illuminated a problem. It took eight years to get the survey’s 20 terabytes of data into the hands of scientists.

“We’re not good at pipeline processing of survey data in a timely manner to feed a community,” Bothun said. “We shouldn’t have to wait eight years to go from acquired pixels to reduced data to analysis. It should just happen instantly. To the extent that it doesn’t is the extent that we’re going to shoot ourselves in the foot and turn astronomy into a science that archives pixels.”

The problem is about to get more challenging. A coalition of institutions is building the Large Synoptic Survey Telescope (LSST) in Chile. The LSST camera will have 3.2 billion pixels, and at 16 bits per pixel, each image it captures will be a whopping 6.4 gigabytes.

“Try to take a selfie of that and send it to your mom over wifi,” Bothun quipped. The challenge, though, is no laughing matter. It’s difficult to move that much data around, and it’s hard to look at it, too.

What you see is not all you get

“Every pixel in astronomy has a source in it. We need to see every pixel. We’re nowhere close to that,” Bothun said. A short-term answer may be visualization walls, commonly called viz walls. These are banks of high-definition monitors that scientists could use to display and manipulate vast amounts of data in one place. This would be perfect for looking at such large, high-resolution images. If you’re seeing a scaled-down version of a photo, Bothun said, the really interesting stuff may simply get averaged out. In addition, it’s better to look at a entire image at native resolution. This will take some training of our brains, but they’re capable.

“Your brain is a great visualizing machine. It’s a great parallel processing machine,” Bothun said. He said if it wasn’t we couldn’t drive on I-5. Think about how it would be if you tried to consciously track the speed and location of every other vehicle around you on the freeway. It’s not possible.
“Your brain does this automatically,” Bothun said. “It’s about time we we started to do data analysis in a forum that matches your brain’s algorithm.”

This would allow us “to take on extremely challenging problems, which is what leads to discovery in science,” he added.

Star Trek to the rescue

Viz walls may not be enough when it comes to the data from LSST. Its ten-year survey of the universe will generate a mind-boggling 60 petabytes of information. To meet the challenge, Bothun’s office is working on advanced visualization tools, a sort of three-dimensional viz cloud.

“It could be the holodeck,” Bothun said in reference to the virtual reality facility in Star Trek. “That’s how you should think of this.”

In this viz cloud trained humans could look at data in real time, and quickly sort out and discard what isn’t useful. After all, Bothun noted, the scientifically interesting data is usually just a tiny fraction of what is collected, and there’s no good reason to be pack rats with the rest.

“If all we’re going to do is take the raw data set and write it to disk, this is not a useful instrument,” he said of the LSST. “We have to do business differently if we want to optimize discovery.”

Big data is here, and visualization of this sort will help astronomers, but it will go beyond that; It can help in fields from finance and business to medicine, climate change, and counter-terrorism. To make effective use of the information available will require solutions to the pipeline and database challenges.

“All of this is absolutely vital for observational astronomy to continue to progress and continue to engage in discovery,” Bothun concluded.

Local editor recognized for work on astro newsletter

Vicki Saunders, editor of BPAA Quarterly, the newsletter for the Battle Point Astronomical Association of Bainbridge Island, recently received fourth place recognition from the Astronomical League in the competition for the Mabel Sterns Newsletter Editor Awards. It’s the third time in the 14-year history of the awards, named for the AL’s first newsletter editor, that BPAA has placed. Saunders received honorable mention in 2006, and Bill and Anna Edmonds took fifth place in 2002.

Mabel Sterns, above, was the first editor of
the Astronomical League newsletter, and now
the league's award for newsletter excellence bears
 her name. Vicki Saunders of the Battle Point
Astronomical Association on Bainbridge Island took
fourth place in this year's awards.
Photo: Astronomical League.

Northwest astronomy clubs have not been all that well represented in the Sterns Awards. Rose City Astronomers from Portland took first place back in 2007 with the Rosette Gazette, edited by Larry Deal. Seattle Astronomical Society‘s Webfooted Astronomer, edited by Laurie Maloney, took a third in 2001, and Kathleen Higgins took second in 2002 for the Boise Astronomical Society newsletter.

The awards have a fairly rigorous nomination process, and Saunders noted that the recognition came despite the fact that she ignored one of the league’s strong suggestions, and that was to include the AL logo, preferably on the first page! The judges, former newsletter editors as well as editors of The Reflector, the Astronomical League magazine, apparently ignored that omission in their deliberations and recognized Saunders’ outstanding publication.

As a former editor of The Webfooted Astronomer, I recognize the challenge of putting out a good product month after month. It’s tough to find or create enough content. BPAA president Stephen Ruhl’s nominating letter was quoted in the AL Reflector in praise of Saunders’ work: “Vicki’s efforts create a newsletter that meeets the needs of the association and that draws the community into astronomy and the BPAA. It is the glue that holds our local astronomical community together.” The winter 2011/12 issue is a good one, with seven feature articles created by club members.

Submissions for the 2012 Mabel Sterns Awards are due by March 31. Complete information about how to apply is on the AL website.

Congratulations to Vicki Saunders, and hats off to all of the astronomy club newsletter editors out there who keep their members informed and engaged.