New questions about Arecibo’s future swirl in the wake of Hurricane Maria

When Hurricane Maria’s 250-kilometer-per-hour winds slammed into Puerto Rico on September 20, they spurred floods, destroyed roads and flattened homes across the island. A week-and-a-half later, parts of the island remain without power, and its people are facing a humanitarian crisis.

The storm also temporarily knocked out one of the best and biggest eyes on the sky: the Arecibo Observatory, some 95 kilometers west of San Juan. The observatory’s 305-meter-wide main dish was until recently the largest radio telescope in the world (a bigger one, the FAST radio telescope, opened in China in 2016).

As news trickled out over the past week, it appeared that the damage may not be as bad as initially reported. The observatory is conserving fuel, but plans to resume limited astronomy observations September 29, deputy director Joan Schmelz tweeted earlier that day. “#AreciboScience is coming back after #MariaPR.”

But the direct whack still raises the issue of when – and even whether – to repair the observatory: Funding for it has repeatedly been on the chopping block despite its historic contributions to astronomy.

Arecibo’s recent work includes searching for gravitational waves by the effect they have on the clocklike regularity of dead stars called pulsars; watching for mysterious blasts of energy called fast radio bursts (SN Online: 12/21/16); and keeping tabs on near-Earth asteroids.

It played a key role in the history of the search for extraterrestrial intelligence: In 1974, astronomers Frank Drake, Jill Tarter and Carl Sagan used it to send messages to any extraterrestrial civilizations that might be listening (SN Online: 2/13/15). It was also the telescope that, in 1992, discovered the first planets outside the solar system.

Arecibo also holds a special place in my personal history: Watching actress Jodie Foster use the giant dish to listen for aliens in the movie Contact when I was 13 cemented my desire to study astronomy. I chose to go to Cornell University for undergrad in part because the university managed Arecibo at the time, and I hoped I might get to go there. (I never did, but my undergrad adviser, Martha Haynes, uses Arecibo to study the distribution of galaxies in the local universe.) And one of the first science stories I ever had published was about Cornell professors testifying to the National Science Foundation, which owns Arecibo, to defend the observatory’s funding.
Ten years after that story ran in the Cornell Daily Sun, Arecibo’s funding situation is still in doubt. It’s not clear how the recent damage will affect its future.

Telescope operator Ángel Vázquez sent the first damage reports via short-wave radio on September 21. A line feed antenna, used to receive and transmit radio waves to study the Earth’s ionosphere, broke off and fell onto the observatory’s main dish, damaging some of its panels. A second, 12-meter dish was thought to have been destroyed entirely.

But the smaller dish survived with only minor damage. “Initial reports said it had just been blown away, but it turned out that was not correct,” says Nicholas White of the Universities Space Research Association, which co-operates the observatory with SRI International, a nonprofit headquartered in Menlo Park, Calif., and Metropolitan University in San Juan, Puerto Rico. “That looks like it’s fine, although obviously we have to get up there and check it out.”

On September 23, observatory director Francisco Córdova posted a picture to the observatory’s Facebook page of two staff members standing in front of the big telescope dish with an outstretched Puerto Rican flag. “Still standing after #HurricaneMaria!” the post declares. “We suffered some damages, but nothing that can’t be repaired or replaced!”
The line feed antenna is a big loss, but it should be replaceable eventually, White says. And the damage to the main dish is fixable. Among the tasks was to get inside the Gregorian dome — the golf ball‒like structure suspended over the giant dish — and make sure the reflectors within it were aligned correctly. (Those reflectors were knocked askew by Hurricane George in 1998, says Cornell radio astronomer Donald Campbell.)

Meantime, Arecibo staff, who managed to safely shelter in place during the storm, “have been showing up for work, funnily enough,” White says. “People just want to get back to normal.”

But normal is also a state of uncertainty. The NSF, which foots $8.3 million of the observatory’s nearly $12 million a year operating costs, has been trying to offload their responsibility for it for several years. (NASA covers the balance.) And NSF’s agreement with the three groups that jointly maintain and operate the observatory runs out in March 2018. In 2016, the NSF called for proposals for other organizations to take over after that.

The NSF can’t estimate yet how expensive the repairs will be or how long they will take to complete, so it’s reserving comment on how the damage will affect decisions about the observatory’s future. “We need to make a complete assessment,” says NSF program director Joseph Pesce.

Personally, I hope the observatory remains open, both for science and for inspiration. I’m still waiting for a reply to that 1974 Arecibo message.

Colliding black holes are reported for a fifth time

Spacetime ripples from black holes are becoming routine.

For a fifth time, scientists have reported the detection of two colliding black holes via their gravitational waves, tiny vibrations that warp the fabric of spacetime. Unlike previous gravitational wave detections, which were heralded with news conferences often featuring panels of scientists squinting at journalists under bright lights, this was a low-key announcement. The event, caught on June 8, 2017, by the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, was unceremoniously unveiled in a paper published online November 15 at arXiv.org.

With masses 7 and 12 times that of the sun, the pair of black holes was the lightest LIGO has spotted so far. The lack of fanfare over the detection signals a shift. Scientists are now aiming to collect data from many black hole crashes. That data can be analyzed to answer questions about the population as a whole, such as how two black holes get paired up in the first place.

Why some birds of paradise have ultrablack feathers

Some birds of paradise really know how to work their angles. Tilted, microscopic filaments in some of the showy birds’ black feathers make that plumage look much darker than traditional black feathers, researchers report online January 9 in Nature Communications.

Dakota McCoy, an evolutionary biologist at Harvard University, and colleagues measured how much light each type of black feather absorbs. Superblack feathers absorb up to 99.95 percent of light that shines directly on them, while traditional black feathers absorb up to 96.8 percent, the researchers found.
Using scanning electron microscopy and nano-CT scanning, the team observed that ultrablack feathers have ragged, spike-studded barbules that curve upward at a roughly 30-degree angle to the tip, creating an array of deep, curved cavities. Traditional black feathers are smoother and lack such detailed microstructures. These spikes and pits scatter light multiple times, allowing for more light absorption and darker plumage, the scientists say. Even when the researchers dusted the feathers with gold, the darkest ones still retained their blackness, while traditional black plumes looked gilded in SEM images.

Superblack patches probably evolved to “exaggerate the perceived brilliance of adjacent color patches” during mating displays, the researchers write.

Venus may be home to a new kind of tectonics

THE WOODLANDS, Texas — Venus’ crust is broken up into chunks that shuffle, jostle and rotate on a global scale, researchers reported in two talks March 20 at the Lunar and Planetary Science Conference.

New maps of the rocky planet’s surface, based on images taken in the 1990s by NASA’s Magellan spacecraft, show that Venus’ low-lying plains are surrounded by a complex network of ridges and faults. Similar features on Earth correspond to tectonic plates crunching together, sometimes creating mountain ranges, or pulling apart. Even more intriguing, the edges of the Venusian plains show signs of rubbing against each other, also suggesting these blocks of crust have moved, the researchers say.
“This is a new way of looking at the surface of Venus,” says planetary geologist Paul Byrne of North Carolina State University in Raleigh.

Geologists generally thought rocky planets could have only two forms of crust: a stagnant lid as on the moon or Mars — where the whole crust is one continuous piece — or a planet with plate tectonics as on Earth, where the surface is split into giant moving blocks that sink beneath or collide with each other. Venus was thought to have one solid lid (SN: 12/3/11, p. 26).

Instead, those options may be two ends of a spectrum. “Venus may be somewhere in between,” Byrne said. “It’s not plate tectonics, but it ain’t not plate tectonics.”

While Earth’s plates move independently like icebergs, Venus’ blocks jangle together like chaotic sea ice, said planetary scientist Richard Ghail of Imperial College London in a supporting talk.
Ghail showed similar ridges and faults around two specific regions on Venus that resemble continental interiors on Earth, such as the Tarim and Sichuan basins in China. He named the two Venusian plains the Nuwa Campus and Lada Campus. (The Latin word campus translates as a field or plain, especially one bound by a fence, so he thought it was fitting.)
Crustal motion may be possible on Venus because the surface is scorching hot (SN: 3/3/18, p. 14). “Those rocks already have to be kind of gooey” from the high temperatures, Byrne said. That means it wouldn’t take a lot of force to move them. Venus’ interior is also probably still hot, like Earth’s, so convection in the mantle could help push the blocks around.

“It’s a bit of a paradigm shift,” says planetary scientist Lori Glaze of NASA’s Goddard Space Flight Center, who was not involved in the new work. “People have always wanted Venus to be active. We believe it to be active, but being able to identify these features gives us more of a sense that it is.”

The work may have implications for astronomers trying to figure out which Earth-sized planets in other solar systems are habitable (SN: 4/30/16, p. 36). Venus is almost the same size and mass as the Earth. But no known life exists on Venus, where the average surface temperature is 462° Celsius and the atmosphere is acidic. Scientists have long speculated that the planet’s apparent lack of plate tectonics might play a role in making the planet so seemingly uninhabitable.

What’s more, the work also underlines the possibility that planets go through phases of plate tectonics (SN: 6/25/16, p. 8). Venus could have had plate tectonics like Earth 1 billion or 2 billion years ago, according to a simulation presented at the meeting by geophysicist Matthew Weller of the University of Texas at Austin.

“As Venus goes, does that predict where the Earth is going in the relatively near future?” he wondered.