Tag Archives: Rose City Astronomers

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 loooking 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 miniscule 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.”

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.


Solstice sunset watch and LIGO info on our calendar this week

The calendar year is winding down, and astronomy clubs are hustling to get a last few events in before we plunge into 2017.

Rose City AstronomersThe Rose City Astronomers eschew their usual formal meeting for their annual holiday potluck at 6:30 p.m. Monday, December 19 at the OMSI auditorium in Portland. Leftovers from the event have traditionally been donated to a homeless shelter, and this year the astronomers are also collecting warm clothing for donations, figuring that astronomy folk may have a supply of such to bring comfort to those late-night sessions at the eyepiece.

The Eastside Astronomical Society will hold its monthly meeting at 7 p.m. Tuesday, December 20 at the Lake Hills Library in Bellevue. NASA Solar System Ambassador John McLaren will give a talk about the history of scientific exploration of the Sun, and look ahead to future efforts to learn even more about our nearest star.

Seattle Astronomical SocietyThe Seattle Astronomical Society will hold its monthly meeting at 7:30 p.m. Wednesday, December 21 in room A102 of the Physics/Astronomy building on the University of Washington campus in Seattle. Joey Key, a professor at the University of Washington-Bothell, will talk about the next LIGO run searching for gravitational waves, which will also involve astronomical collaboration is search of an elusive “multimessenger source,” a signal that could be detected both in gravitational waves and electromagnetic radiation. Interesting stuff!


VMMEPPThe Viking Mars Missions Education and Preservation Project plans an informal information session for 4 p.m. Tuesday, December 20 at the Hillsdale Library in Portland. This family-friendly event will feature artifacts from the Viking mission, activities for kids, and lots of information about Viking history. Check out our recent article and podcast about the project. The year end is a good time to lend a little financial support to this great history project, too!

Solstice sunset watch

Join Alice Enevoldsen of Alice’s Astro Info and watch the first sunset of winter at 3:45 p.m. Wednesday, December 20 at Solstice Park in West Seattle. The solstice is at 2:44 a.m. PST on Wednesday. Sunset that evening is officially listed as 4:20 p.m., but Enevoldsen says they’ve noted that it’s typically about ten minutes early because of the horizon at that spot. She gives a fun and informative presentation about the mechanics of the seasons, and is persistent about it—this will be her thirty-first seasonal sunset watch. That’s a lot of solstices and equinoxes! Come by even if it’s cloudy, because the Sun sometimes sneaks through anyway, but driving rain makes it a no-go.

Futures file

You can scout out future astronomy events on our calendar. The page also features a full schedule of planetarium and stage science shows at Pacific Science Center.

Up in the sky

The Ursid meteor shower peaks this week. This Week’s Sky at a Glance from Sky & Telescope magazine and The Sky This Week from Astronomy offer more observing highlights for the week.


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

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.

Observatory plans

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

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.


New Space conference, and science news meets science fiction this week

The 2016 New Space Conference will be held in Seattle this week, and the city will see five world premiere plays about astronomy and other sciences next weekend.

New Space

New SpaceThis year’s New Space Conference, presented by the Space Frontier Foundation, will be held June 21-23 in Seattle. The conference brings the three pillars of the space industry—startups, established companies, and government agencies—together with private investors and tech innovators. The three-day conference focuses on the current, near term, and future issues and challenges in commercial space and is attended by distinguished members from all sectors and verticals of the space industry, making this conference a hotbed of innovation and partnership.

This conference has been held annually since 2006, and each since 2009 has been held in the Silicon Valley. This year’s is the first to be held in Seattle, in recognition of the city’s growing status as a hub for companies involved in the space industry.

Seattle Astronomy will be attending the conference and will post dispatches about the sessions.

Art meets science

CentrifugeScience news meets science fiction this week as Infinity Box Theatre Project presents Centrifuge, a project that will result in five world-premiere one-act plays based on the latest science headlines. Five pairs of playwrights and science writers will create presentations based on a theme drawn at random on Monday evening. The science writers will help inform the playwrights about the science involved, then the playwrights will have two days to write a ten-minute play, while the science writers create brief presentations about the science presented in the plays. Teams of actors, directors, and designers will run with the scripts starting with rehearsals Wednesday, and the plays will be performed, preceded by the presentations by science writers, beginning at 8 p.m. both Friday, June 24 and Saturday, June 25 at Stage One Theater at North Seattle College.

There will be at least one astronomy-themed play, as Greg Scheiderer of Seattle Astronomy is one of the science writers participating in this interesting project.

There’s more information on the Infinity Box website. Tickets are available online as well. Don’t miss this event, a partner project of the 14/48 Projects.

Rose City

Rose City AstronomersRose City Astronomers will hold their monthly meeting at 7:30 p.m. Monday, June 20 at the Oregon Museum of Science and Industry in Portland. Jim Todd, director of space science education and manager of the Kendall Planetarium at the museum, will be the guest speaker, on the topic of OMSI’s plans to partner with the Salem Fairgrounds for viewing of the total solar eclipse that will occur on August 21, 2017. The eclipse event will feature science lectures, astronomy-related community groups, entertainment, and more.


The Tacoma Astronomical Society plans one of its free public nights for 9 p.m. Saturday, June 25 at the Fort Steilacoom campus of Pierce College. The all-weather program will be about the Sun, and if the skies are clear club members will be on hand with telescopes for observing.


AstronoMay continues at PacSci with two talks this week

Saturday was Astronomy Day, but the Pacific Science Center is taking the whole month to celebrate AstronoMay! Two interesting talks highlight the calendar for the week.

Brett Morris

Brett Morris

Brett Morris, one of the co-founders of Astronomy on Tap Seattle, will give a presentation titled, “Hunting For Life in the Universe” at a Teen Science Café at 7 p.m. Wednesday, May 18 at the center’s PACCAR IMAX Theater. Morris will introduce the science of astrobiology and how it seeks to measure and locate the conditions necessary for life in the universe. He’ll talk about telescopes and techniques used to explore other worlds and to try to track down life on them.

Dr. Will Grundy, the lead investigator for the surface composition team of New Horizons, will give a talk titled, “Pluto and Charon Up-close” at 2:15 p.m. Sunday, May 22 at the PACCAR Theater. Grundy will show close-up images from the mission and discuss his research, which involves icy outer solar system planets, satellites, and Kuiper belt objects using a broad variety of observational, theoretical, laboratory, and space-based techniques.

Volunteers from the Seattle Astronomical Society will be on hand at the center Saturday and Sunday with solar telescopes for viewing of the Sun. AstronoMay also includes planetarium shows, screenings of the movie A Beautiful Planet 3D, and other activities. Check the AstronoMay calendar page for a full listing.

Club events

saslogoThe Seattle Astronomical Society will hold its monthly meeting at 7:30 p.m. Wednesday, May 18 in room A102 of the Physics/Astronomy building on the campus of the University of Washington in Seattle. Solar System Ambassador Ron Hobbs will give a talk titled, “Juno to Jupiter: Piercing the Veil.” The Juno spacecraft will arrive at Jupiter in July. Over the ensuing year and a half, it will peer through the Jovian cloud tops and provide a deeper understanding of the composition and structure of the Solar System’s largest planet. Hobbs will explain what exciting science to expect from NASA’s latest outer planet mission.

Rose City AstronomersRose City Astronomers will hold their monthly meeting at 7:30 p.m. Monday, May 16 at the OMSI auditorium in Portland. It will be the group’s annual astronomy fair, with a swap meet, info booths, and brief show-and-tell sessions.

TJO open house

Theodor Jacobsen ObservatoryThere will be an open house at the University of Washington’s Theodor Jacobsen Observatory at 9 p.m. Wednesday, May 18. Students Cale Lewandowski and Jason Busnardo will be giving a talk about how to overcome the challenges of a trip to Mars. Reservations are strongly recommended for the talks, which are held in a small classroom in the observatory and often fill up early. Volunteers from the Seattle Astronomical Society will offer tours of the observatory and a look through its vintage telescope if weather permits.

Up in the sky

Mars is nearing opposition and Jupiter remains well placed for observing. This Week’s Sky at a Glance from Sky & Telescope magazine and The Sky This Week from Astronomy have other observing highlights for the week.


Transit of Mercury highlight of the week; maybe the year

The most anticipated observing event of the year happens Monday morning, May 9, as Mercury will transit across the face of the Sun. The transit begins at 4:13 a.m. Pacific Daylight Time, so it will be under way when the Sun rises in Seattle.

NASA illustration.

NASA illustration.

The weather gods are taunting Seattle astronomers, as usual. After a pretty good run of mostly clear weather, we awoke to rain on Mother’s Day morning. The forecast is for mostly cloudy cloudy skies around sunrise Monday, turning to sunny by noon, when the transit will be over. So, it’s pretty unlikely that we’ll see the transit constantly from sun-up to finish, but also looks pretty unlikely that we’ll get skunked.

There are several transit-observing events that we know about. Seattle Astronomy will be down at Seacrest Park near the West Seattle Water Taxi dock with a telescope; join us and have a look! The Seattle Astronomical Society will hold an observing event at Snoqualmie Point Park near the town of Snoqualmie. (UPDATE: The SAS event has been cancelled due to inclement weather.) There will be transit viewing and programming at the Pierce College Science Dome in Lakewood. Rose City Astronomers and the Oregon Museum of Science and Industry will be observing the transit from the OMSI site in Portland. Check the links for details.

A couple of things to keep in mind about the transit. First, don’t ever, ever, ever look at the Sun without proper protection. Regular sunglasses won’t do the trick. You need special eclipse glasses. Second, Mercury is so small that you will need magnification to see it, and that means a telescope also equipped with the proper solar filters. Be safe out there!

Read our preview article about the Mercury transit.

AstronoMay continues

Pacific Science CenterAstronoMay continues at the Pacific Science Center this week. There will be two interesting lectures on Saturday, May 14. At 10 a.m. Elena Amador, a graduate student at the University of Washington, will talk about the search for water on Mars. Then at 2:30 p.m. Dr. Sandeep Singh, a planetary scientist from the Bear Fight Institute in Winthrop, will speak about Saturn’s largest moon Titan. Singh has worked on NASA’s Rosetta, Cassini, and DAWN missions.

Volunteers from the Seattle Astronomical Society will be on hand much of the day Saturday with solar telescopes for observing the Sun, and the center is offering planetarium shows and other astronomy-related programming throughout the week. Check their calendar for details.

PacSci Podcast about AstronoMay:

Club events

Tacoma Astronomical SocietyThe Tacoma Astronomical Society will host one of its public nights beginning at 9 p.m. this Saturday, May 14 on the Fort Steilacoom campus of Pierce College. The program will be about black holes, and there will be observing if the weather permits.

BPAAThe Battle Point Astronomical Association has several events on Saturday, May 14 at its Edwin Ritchie Observatory in Battle Point Park on Bainbridge Island. At their BPAstro Kids shows at 5 p.m. and 6 p.m. youngsters will build their own planets and check them for life. Following at 8 p.m. astronomer Steve Ruhl will examine exoplanets: How we see them, what they tell us about our solar system, and how we might know if there other habitable worlds out there.

Check out our recent article and podcast about BPastro Kids:

Up in the sky

The Mercury transit is the big astronomical event of the week. The Sky This Week from Astronomy magazine and This Week’s Sky at a Glance from Sky & Telescope have other observing highlights for the week.


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.

Dr. Ethan Siegel, creator of the "Starts With a Bang" blog, gave a talk about the discovery of gravitational waves to the Rose City Astronomers April 18. Photo: Greg Scheiderer.

Dr. Ethan Siegel, creator of the “Starts With a Bang” blog, gave a talk about the discovery of gravitational waves to the Rose City Astronomers April 18. Photo: Greg Scheiderer.

“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.”

Siegel, an entertaining and informative speaker, is scheduled to give another talk at the October 2016 meeting of Rose City Astronomers. He will discuss his book Beyond the Galaxy.

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.”