A Fifth Force: Fact or Fiction?

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A Fifth Force: Fact or Fiction?

  • A Fifth Force: Fact or Fiction?
Has a Hungarian lab really found evidence of a fifth force of nature?

Credit: Jurik Peter / Shutterstock.com

Don Lincoln is a senior scientist at the U.S. Department of Energy’s Fermilab, America’s largest Large Hadron Collider research institution. He also writes about science for the public, including his recent “The Large Hadron Collider: The Extraordinary Story of the Higgs Boson and Other Things That Will Blow Your Mind” (Johns Hopkins University Press, 2014). You can follow him onFacebook. Lincoln contributed this article to Live Science’s Expert Voices: Op-Ed & Insights.

Science and the internet have an uneasy relationship: Science tends to move forward through a careful and tedious evaluation of data and theory, and the process can take years to complete. In contrast, the internet community generally has the attention span of Dory, the absent-minded fish of “Finding Nemo”(and now “Finding Dory”) — a meme here, a celebrity picture there — oh, look … a funny cat video.

Thus people who are interested in serious science should be extremely cautious when they read an online story that purports to be a paradigm-shifting scientific discovery. A recent example is one suggesting that a new force of nature might have been discovered. If true, that would mean that we have to rewrite the textbooks.

As a physicist, I’d like to shed a disciplined scientific light on the claim.

[Beyond Higgs: 5 Elusive Particles That May Lurk in the Universe]

So what has been claimed?

In an article submitted on April 7, 2015, to the arXiv repository of physics papers, a group of Hungarian researchers reported on a study in which they focused an intense beam of protons (particles found in the center of atoms) on thin lithium targets. The collisions created excited nuclei of beryllium-8, which decayed into ordinary beryllium-8 and pairs of electron-positron particles. (The positron is the antimatter equivalent of the electron.)

The Standard Model is the collection of theories that describe the smallest experimentally observed particles of matter and the interactions between energy and matter.

Credit: Karl Tate, LiveScience Infographic Artist

They claimed that their data could not be explained by known physical phenomena in the Standard Model, the reigning model governing particle physics. But, they purported, they could explain the data if a new particle existed with a mass of approximately 17 million electron volts, which is 32.7 times heavier than an electron and just shy of 2 percent the mass of a proton. The particles that emerge at this energy range, which is relatively low by modern standards, have been well studied. And so it would be very surprising if a new particle were discovered in this energy regime.

However, the measurement survived peer review and was published on Jan. 26, 2016, in the journalPhysical Review Letters, which is one of the most prestigious physics journals in the world. In this publication, the researchers, and this research, cleared an impressive hurdle. [What’s That? Your Physics Questions Answered]

Their measurement received little attention until a group of theoretical physicists from the University of California, Irvine (UCI), turned their attention to it. As theorists commonly do with a controversial physics measurement, the team compared it with the body of work that has been assembled over the last century or so, to see if the new data are consistent or inconsistent with the existing body of knowledge. In this case, they looked at about a dozen published studies.

What they found is that though the measurement didn’t conflict with any past studies, it seemed to be something never before observed — and something that couldn’t be explained by the Standard Model.

To make sense of the Hungarian measurement, then, this group of UCI theorists invented a new theory.

The theory invented by the Irvine group is really quite exotic. They start with the very reasonable premise that the possible new particle is something that is not described by existing theory. This makes sense because the possible new particle is very low mass and would have been discovered before if it were governed by known physics. If this were a new particle governed by new physics, perhaps a new force is involved. Since traditionally physicists speak of four known fundamental forces (gravity, electromagnetism and the strong and weak nuclear forces), this hypothetical new force has been dubbed “the fifth force.”

Theories and discoveries of a fifth force have a checkered history, going back decades, with measurements and ideas arising and disappearing with new data. On the other hand, there are mysteries not explained by ordinary physics like, for example, dark matter. While dark matter has historically been modeled as a single form of a stable and massive particle that experiences gravity and none of the other known forces, there is no reason that dark matter couldn’t experience forces that ordinary matter doesn’t experience. After all, ordinary matter experiences forces that dark matter doesn’t, so the hypothesis isn’t so silly.

There is no reason dark matter couldn't experience forces that ordinary matter doesn't experience. Here, in the galaxy cluster Abell 3827, dark matter was observed interacting with itself during a galaxy collision.

There is no reason dark matter couldn’t experience forces that ordinary matter doesn’t experience. Here, in the galaxy cluster Abell 3827, dark matter was observed interacting with itself during a galaxy collision.

Credit: ESO

There are many ideas about forces that affect only dark matter and the term for this basic idea is called “complex dark matter.” One common idea is that there is a dark photon that interacts with a dark charge carried only by dark matter. This particle is a dark matter analog of the photon of ordinary matter that interacts with familiar electrical charge, with one exception: Some theories of complex dark matter imbue dark photons with mass, in stark contrast with ordinary photons. [Gallery: Dark Matter Throughout the Universe]

If dark photons exist, they can couple with ordinary matter (and ordinary photons) and decay into electron-positron pairs, which is what the Hungarian research group was investigating. Because dark photons don’t interact with ordinary electric charge, this coupling can only occur because of the vagaries of quantum mechanics.  But if scientists started seeing an increase in electron-positron pairs, that might mean they were observing a dark photon.

The Irvine group found a model that included a “protophobic” particle that was not ruled out by earlier measurements and would explain the Hungarian result. Particles that are “protophobic,” which literally means “fear of protons,” rarely or never interact with protons but can interact with neutrons (neutrophilic).

The particle proposed by the Irvine group experiences a fifth and unknown force, which is in the range of 12 femtometers, or about 12 times bigger than a proton. The particle is protophobic and neutrophilic. The proposed particle has a mass of 17 million electron volts and can decay into electron-positron pairs. In addition to explaining the Hungarian measurement, such a particle would help explain some discrepancies seen by other experiments. This last consequence adds some weight to the idea.

So this is the status.

What is likely to be true? Obviously, data is king. Other experiments will need to confirm or refute the measurement. Nothing else really matters. But that will take a year or so and having some idea before then might be nice. The best way to estimate the likelihood the finding is real is to look at the reputations of the various researchers involved. This is clearly a shoddy way to do science, but it will help shade your expectations.

So let’s start with the Irvine group. Many of them (the senior ones, typically) are well- regarded and established members of the field, with substantive and solid papers in their past. The group includes a spectrum of ages, with both senior and junior members.  In the interest of full disclosure, I know some of them personally and, indeed, two of them have read the theoretical portions of chapters of books I have written for the public to ensure that I didn’t say anything stupid. (By the way, they didn’t find any gaffes, but they certainly helped clarify certain points.) That certainly demonstrates my high regard for members of the Irvine group, but possibly taints my opinion. In my judgment, they almost certainly did a thorough and professional job of comparing their new model to existing data.  They have found a small and unexplored region of possible theories that could exist.

On the other hand, the theory is pretty speculative and highly improbable. This isn’t an indictment … all proposed theories could be labeled in this way. After all, the Standard Model, which governs particle physics, is nearly a half century old and has been thoroughly explored. In addition, ALL new theoretical ideas are speculative and improbable and almost all of them are wrong. This also isn’t an indictment. There are many ways to add possible modifications to existing theories to account for new phenomena. They can’t all be right. Sometimes none of the proposed ideas are right.

However, we can conclude from the reputation of the group’s members that they have generated a new idea and have compared it to all relevant existing data. The fact that they released their model means that it survived their tests and thus it remains a credible, if improbable, possibility.

What about the Hungarian group? I know none of them personally, but the article was published in Physical Review Letters — a chalk mark in the win column. However, the group has also published two previous papers in which comparable anomalies were observed, including a possible particle with a mass of 12 million electron volts and a second publicationclaiming the discovery of a particle with a mass of about 14 million electron volts. Both of these claims were subsequently falsified by other experiments.

Further, the Hungarian group has never satisfactorily disclosed what error was made that resulted in these erroneous claims. Another possible red flag is that the group rarely publishes data that doesn’t claim anomalies. That is improbable. In my own research career, most publications were confirmation of existing theories. Anomalies that persist are very, very, rare.

So what’s the bottom line? Should you be excited about this new possible discovery?  Well…sure…possible discoveries are always exciting. The Standard Model has stood the test of time for half a century, but there are unexplained mysteries and the scientific community is always looking for the discovery that points us in the direction of a new and improved theory. But what are the odds that this measurement and theory will lead to the scientific world accepting a new force with a range of 12 fm and with a particle that shuns protons? My sense is that this a long shot. I am not so sanguine as to the chances of this outcome.

Of course, this opinion is only that…an opinion, albeit an informed one. Other experiments will also be looking for dark photons because, even if the Hungarian measurement doesn’t stand up to scrutiny, there is still a real problem with dark matter.  Many experiments looking for dark photons will explore the same parameter space (e.g. energy, mass and decay modes) in which the Hungarian researchers claim to have found an anomaly. We will soon (within a year) know if this anomaly is a discovery or just another bump in the data that temporarily excited the community, only to be discarded as better data is recorded.  And, no matter the outcome, good and better science will be the eventual result.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on FacebookTwitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.


Rare Noah’s Ark Mosaic Uncovered in Ancient Synagogue in Israel

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Rare Noah’s Ark Mosaic Uncovered in Ancient Synagogue in Israel

Rare Noah's Ark Mosaic Uncovered in Ancient Synagogue in Israel

A mosaic floor panel depicts soldiers being swallowed by large fish, surrounded by overturned chariots in the parting of the Red Sea

Credit: Baylor University

Mosaics depicting prominent Bible scenes were uncovered during annual excavations of an ancient synagogue in Israel’s Lower Galilee.

During the excavation in June, archaeologists found two new panels of amosaic floor in a Late Roman (fifth-century) synagogue at Huqoq, an ancient Jewish village. One panel showed Noah’s ark with pairs of animals, such as lions, leopards and bears. The other panel depicted soldiers being swallowed by large fish, surrounded by overturned chariots in the parting of the Red Sea.

Such images are extremely rare for the time period, according to excavation director Jodi Magness, of the University of North Carolina at Chapel Hill, whose work was funded by the National Geographic Society.

“I know of only two other scenes of the parting of the Red Sea in ancient synagogues,” Magness told National Geographic.

“One is in the wall paintings at Dura Europos [in Syria], which is a complete scene but different from ours — no fish devouring the Egyptian soldiers,” Magness said. “The other is at Wadi Hamam [in Israel], but that’s very fragmentary and poorly preserved.”

The Noah’s ark mosaic included pairs of animals, such as lions, leopards, bears, and donkeys.

Credit: Baylor University

The ark scenes are also uncommon; Magness said she knows of only two other mosaics showing such depictions.

Along with a team of university scholars and students, and the Israel Antiquities Authority, Magness has excavated at Huqoq since 2012. Previous mosaic discoveries have depicted Bible scenes such as Samson and the foxes and Samson carrying the gate of Gaza on his shoulders.

The Huqoq excavations revealed the first nonbiblical mosaic found in an ancient synagogue. That three-tiered mosaic included a scene showing a meeting between two important male figures, thought to be the legendary meeting between Alexander the Great and the Jewish high priest.

These previous discoveries were uncovered in the synagogue’s eastern aisle, and the researchers were uncertain whether the mosaics would continue into the nave, the large central area of the synagogue. However, the excavations did, indeed, reveal the Red Sea and Noah’s ark mosaics.

“This panel is exactly as it should be,” Magness said of the ark mosaic. “It’s facing north, so people could see it as they entered from the south,” where the main door would have been located.

Excavations at this site also uncovered coins spanning 2,300 years.

“The ancient coins … are critical for our knowledge of the monumental synagogue and the associated village,” Nathan Elkins, a member of the research team and a professor of art history at Baylor University, said in a statement.

As is the case after each excavation season, the researchers will remove the uncovered mosaics for conservation and backfill the excavated areas. Excavations are scheduled to continue in the summer of 2017.

Original article on Live Science.

Photos: Unusual Mosaics Decorated Ancient Synagogue in Israel

Richly colorful mosaics unearthed from an archaeological dig in northern Israel tell stories both secular and biblical. From gold-armored elephants to Samson and his flowing locks, images on the mosaics share vivid tales of times long gone. The dig is ongoing and led by archaeologists Jodi Magness, a professor of early Judaism at the University of North Carolina at Chapel Hill. Magness is working with Israeli authorities as well as students from UNC Chapel Hill. (All images courtesy of Jim Haberman.) [Read the full Huqoq mosaic discovery story]

Theater mask

A section of the mosaic showing a theater mask uncovered in summer 2015 at an archeological dig in the town of Huqoq in northern Israel.

Prancing elephant

A section of the mosaic showing an elephant discovered in 2013. This section is part of the larger mosaic exposed in summer 2015.

In command

Archaeological dig leader Jodi Magness standing on a wall within the excavation site.

Samson’s Feat

A section of the mosaic showing Samson carrying the gate of Gaza discovered in 2013 at an archeological dig in the town of Huqoq in northern Israel.

Team effort

Students pulling out stones in the archaeological dig in Huqoq, Israel in 2013.

Tireless work

Moving dirt at the archaeological dig in Huqoq, Israel.

Elizabeth Goldbaum is on Twitter. Follow Live Science @livescience,Facebook & Google+.

Amazing Images: The Best Science Photos of the Week

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Amazing Images: The Best Science Photos of the Week

Each week we find the most interesting and informative articles we can and along the way we uncover amazing and cool images. Here you’ll discover 10 incredible photos and the stories behind them.

The chinstraps:

Volcanic ash presents an uncertain future for penguin nesting grounds.

[Full Story: Covered in Ash: Chinstrap Penguins Threatened by Volcanic Eruption]

Wrinkly ant:

Golden spines and intricate wrinkles make a new ant species magnificent.

[Full Story: ‘Fearsome Raisin’ Ant Sports Striking Fingerprint Pattern]

Fanged spider mummy:

About 99 million years ago, two bizarre spiders — each sporting hard, armored plates on their bodies and horns on their fangs — became mummified in sticky tree resin that turned into amber.

[Full Story: 99-Million-Year-Old Spider Mummy Sported Horned Fangs ]

Fearsome tarantula:

A fearsome tarantula covered in bizarre “attack” hairs has been discovered in a mountain range in Colombia. As an homage to the country where the new species was found, scientists named it Kankuamo marquezi, after Colombian author Gabriel García Márquez.

[Full Story: Love in the Time of Tarantulas? Newfound Spider Named for Márquez]

Tiny soldiers:

Tiny water fleas customize their defenses when they sense predators in the water.

[Full Story: Armor Up! Water Fleas Grow Helmets and Spines for Battle]

Teeth and legs:

A giant, toothy centipede with countless legs is also a swimming fiend, making it the first known aquatic centipede on record. And it’s venomous, to boot, researchers found.

[Full Story: Nightmarish Find: Giant, Venomous Centipede Is a Powerful Swimmer]

Earth’s lava lamp:

The Earth’s mantle is like a mysterious Lava Lamp.

[Full Story: Massive ‘Lava Lamp’ Blobs Deep Inside Earth Have Scientists Puzzled]

Electric clouds:

Bright blue-white noctilucent clouds danced over the town of Nykøbing Mors in Denmark just before dawn on July 1.

[Full Story: Shining Silver-Blue Clouds Captured in Night Sky Photo]

Stingray bot:

A new robot stingray can swim with help from an unexpected source: muscle cells that were taken from rat hearts, a new study finds.

[Full Story: Stingray Robot Uses Light-Activated Rat Cells to Swim]

Galaxy stirring:

Before it died, Japan’s Hitomi satellite revealed surprising insights about how black holes stir up gas inside enormous collections of galaxies.

[Full Story: Galaxy Stirring Revealed by Doomed Japanese Spacecraft]

New Cancer Therapy Leaves Three Dead

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New Cancer Therapy Leaves Three Dead

Yesterday 2:53pm

Credit: Wellcome Images

Clinical trials of a promising new therapy, in which white blood cells are reprogrammed to attack cancer cells, has resulted in the deaths of three patients. In response, the US Food and Drug Administration has ordered a temporary halt to the trial.

The new therapy, called JCAR015 (also known as the “ROCKET” trial), uses genetically engineered immune cells—known as CAR-T cells—to treat acute lymphoblastic leukemia (ALL) in adults, a cancer of the immune system that starts from the early version of white blood cells called lymphocytes in the bone marrow. Once these juiced-up CAR-T cells are reintroduced into the patient’s bloodstream, they should prevent cancer from spreading and taking hold. In a study conducted earlier this year, 94 percent of terminally ill patients who were treated with CAR-T went into remission.

It’s an incredibly promising new approach to battling cancer—but now there’s been a major setback. Three patients, all under the age of 25, have died in a Juno Therapeutics Phase II clinical trial that’s been using the CAR-T cells to treat ALL. The patients died after excess fluids accumulated in their brains (cerebral edemas). In all cases, the deaths happened after a chemotherapy drug, fludarabine, was added to the treatment regimen.

The first death happened in May, but Juno wasn’t certain about the cause of death, saying “a change at that time was not warranted.” The subsequent deaths of two more patients, both from cerebral edemas, in the last week prompted the attention of the FDA, who issued an immediate, but temporary, halt to the trials.

Juno is blaming the deaths on the decision to introduce fludarabine into the treatment, a chemical cocktail that works to flush out the patient’s existing immune cells. Accordingly, the company has asked to re-start the trials, but without the benefit of fludarabine. The FDA wants Juno to revise its patient consent forms, investigative brochure, trial protocol, and a presentation it made to the FDA yesterday. Of the 90 patients expected to participate in the study, only 20 have been enrolled so far.

Despite Juno’s claim, there’s no conclusive evidence that the chemotherapy was responsible for the cerebral edemas. Dr. Stephan Grupp, a professor at the University of Pennsylvania Perelman School of Medicine, is in the midst of a similar trial that uses CAR-T cells to treat patients with pediatric acute lymphoblastic leukemia. He says it’s premature to pin the blame on fludarabine. Grupp’s team has not seen any significant brain swelling in their patients, who have been receiving the same chemotherapy drug. A few central nervous system issues have been observed, including confusion, aphasia, and seizures, but they’ve all all been resolved.

“Obviously, it is always hard to attribute toxicity to the chemo as opposed to the CAR-T cells when both are given around the same time, but we believe the self-limited CNS side effects we have reported from our study are more likely to be due to the T cells,” noted Grupp. “Right now, I don’t see this affecting other CAR-T trials or the field as a whole, since this issue appears not be seen more broadly. There may be some discussion about the appropriate role of the drug fludarabine, but this wouldn’t be a central issue.”

As reported in Yahoo! Finance, news of the patient deaths sent Juno’s share price down 31 percent late yesterday. Investors are obviously nervous, but it’s too early to panic about this promising new approach to cancer therapy. Science is hard, and regrettably, there are bound to be setbacks such as this.

[STAT, Yahoo! Finance]

George is a contributing editor at Gizmodo and io9.

There’s a Secret Message Written Into the Sands of Mars

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There’s a Secret Message Written Into the Sands of Mars

Yesterday 3:15pm

Image: NASA/JPL/University of Arizona

NASA has spotted something strange and beautiful in the sands of Mars—a remarkable dune field that looks eerily similar to Morse code. And it has a message for us.

The dunes in this photo were recently spotted by Hi-RISE, a visible light and near-IR camera that’s been snapping stunning portraits of the Red Planet’s surface from its perch aboard NASA’s Mars Reconnaissance Orbiter since 2006. According to Veronica Bray, the Hi-RISE targeting specialist who analyzed the image, dot and dash features like these have been spotted on Mars before. But in this photo of the Hagal Dune field just south of Mars’ north polar cap, the code-like pattern is especially clear due to unusual topography.

Specifically, a nearby circular depression (probably a sand-filled impact crater) has “focused the wind, and also limited the amount of sand available for formation of the dunes,” Bray told Gizmodo.

The dashes are formed by bidirectional winds—that is, winds coming from either direction perpendicular to the dune itself, which funnel sand into a line. The dots (technically “barchanoid dunes”) are what happens when something interrupts this line-drawing process, although the exact mechanism remains unknown. Bray, not herself a dune specialist, speculates that the barchanoid dunes could be the result of dashes getting stretched out by winds.

Dune formation and migration on Mars is a hot field of study, because the barren, (mostly) water-free surface offers a natural test lab for understanding how wind sculpts landscapes. But in many ways, the dunes of Mars are fundamentally different from the dunes of Earth, owing to the atmosphere’s low density. Often, Martian dunes look more like features we’d expect to see underwater.

While geophysicists continue to work out exactly how Morse code dune fields are forming on Mars, Bray took it upon herself to decode this one’s message:


If any hidden Reptilians among us would like to offer an interpretation, please spare no details in the comments.

Maddie is a staff writer at Gizmodo

This Is the Last Thing Japan’s Lost Black Hole Satellite Saw Before It Died

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This Is the Last Thing Japan’s Lost Black Hole Satellite Saw Before It Died

Wednesday 1:00pm

Hitomi’s final observations (Image: Hitomi Collaboration/JAXA, NASA, ESA, SRON, CSA)

Earlier this year, Japan launched a groundbreaking black-hole-monitoring satellite—only to lose control of it almost immediately under strange circumstances. Now, we finally can see what Hitomi did right before it died.

When JAXA launched Hitomi in February of this year, scientists were giddy over the possibilities of what the black hole monitoring satellite might tell us about the mysteries of the universe. It was only up there a month when something went wrong. A series of unfortunate events caused by both human errors and software flaws sent the satellite spinning out of control. Despite attempts to regain control, Hitomi continued to spin and throw debris into space. Eventually, JAXA declared that the $273 million satellite was beyond recovery.

When Hitomi died, though, researchers also announced that they’d managed to scrape a little bit of data from the satellite and would be detailing it in upcoming papers. Some of that data is out today in a new paper in Nature, which shows Hitomi’s final observation. It has some fascinating implications for what we know about the role of black holes in galaxy formation.

Hitomi’s final observations were of the Perseus Cluster, a galaxy cluster 240 million light years away with a supermassive black hole at its center. The satellite was able to get this view of the galaxy, as well as to measure its x-ray activity:

Researchers expected to see teeming activity in the center of the cluster, but Hitomi’s final x-ray observations showed very little action.

“The intracluster gas is quieter than expected,” co-author Andrew Fabian of Cambridge University told Gizmodo. “We expected that the level would be higher based on the activity of the central galaxy.”

But the finding isn’t just a surprising oasis of calm in a turbulent galaxy. It also gives us insight into just what role black holes play in how galaxies do—or don’t—form.

“The surprise is that it turns out that the energy being pumped out of the black hole is being very efficiently absorbed,” co-author Brian McNamara of the University of Waterloo told Gizmodo. “This hot gas that we’re looking at with Hitomi is the stuff of the future, it’s the gas out of which galaxies form. There is much more of this hot gas than there are stars in the galaxy, or there’s more stuff that wasn’t made into galaxies than that was.”

That means that nearby black holes play a big role in the eventual size of a galaxy. “What it shows is that black holes very effectively control the growth rate of galaxies,” said McNamara.

Of course, the finding underscores how little we still know about the role of black holes in galaxy formation. It also gives us a tantalizing look at how much promise the satellite held before it was lost.

The loss is even bigger because Hitomi marked what researchers hoped would be the end of a long-standing struggle to finally stick an x-ray microcalorimeter—a device used to take incredibly precise measurements of the energy in x-rays—into space. The findings in today’s study were based on just a very small sample of data researchers were able to get from Hitomi’s microcalorimeter before it was lost, and it already has them speculating over what could have been.

“The measurements on the Perseus Cluster showed the potential of the Hitomi x-ray microcalorimeter to transform our understanding of the velocities of hot gas throughout the Universe,” Fabian said.

Before Hitomi, there were two other attempts to send a microcalorimeter into space—and both ended in strange accidents. In 2000, a rocket mission that would have sent the first microcalorimeter into space exploded upon launch. In 2005, a microcalorimeter actually made it into space, but was destroyed by a coolant leak. It wasn’t until 2016 with Hitomi that a microcalorimeter was successfully launched long enough to take take measurements—only to be lost along with the entire satellite shortly after.


“It’s a huge loss, because just from that glimpse we can see the wonderful science that might have been over the next five years,” said McNamara. “We had a whole landscape of planned observations and that first glimpse we got with the detector shows the richness of what we could find. There were surely discoveries that would have been made when we opened that window.”

Still, even though Hitomi’s microcalorimeter and the observations it would have made are lost, there are other opportunities to send another microcalorimeter into space aboard some other upcoming mission.“There loss, but there’s also hope, we never give up,” McNamera said. “We’re hoping we can still get one there.”