On Sept. 26, 2022, at 7:14 pm EDT, DART intentionally crashed into Dimorphos, the asteroid moonlet in the double-asteroid system of Didymos. It was the world’s first test of the kinetic impact mitigation technique, using a spacecraft to deflect an asteroid that poses no threat to Earth, and modifying the object’s orbit. DART is a test for defending Earth against potential asteroid or comet hazards.

The coordinated Hubble and Webb observations are more than just an operational milestone for each telescope — there are also key science questions relating to the makeup and history of our solar system that researchers can explore when combining the capabilities of these observatories.

“Webb and Hubble show what we’ve always known to be true at NASA: We learn more when we work together,” said NASA Administrator Bill Nelson. “For the first time, Webb and Hubble have simultaneously captured imagery from the same target in the cosmos: an asteroid that was impacted by a spacecraft after a seven-million-mile journey. All of humanity eagerly awaits the discoveries to come from Webb, Hubble, and our ground-based telescopes — about the DART mission and beyond.”

Observations from Webb and Hubble together will allow scientists to gain knowledge about the nature of the surface of Dimorphos, how much material was ejected by the collision, and how fast it was ejected. Additionally, Webb and Hubble captured the impact in different wavelengths of light — Webb in infrared and Hubble in visible. Observing the impact across a wide array of wavelengths will reveal the distribution of particle sizes in the expanding dust cloud, helping to determine whether it threw off lots of big chunks or mostly fine dust. Combining this information, along with ground-based telescope observations, will help scientists to understand how effectively a kinetic impact can modify an asteroid’s orbit.

Webb Captures Impact Site Before and After Collision

Webb took one observation of the impact location before the collision took place, then several observations over the next few hours. Images from Webb’s Near-Infrared Camera (NIRCam) show a tight, compact core, with plumes of material appearing as wisps streaming away from the center of where the impact took place.

Observing the impact with Webb presented the flight operations, planning, and science teams with unique challenges, because of the asteroid’s speed of travel across the sky. As DART approached its target, the teams performed additional work in the weeks leading up to the impact to enable and test a method of tracking asteroids moving over three times faster than the original speed limit set for Webb.

“I have nothing but tremendous admiration for the Webb Mission Operations folks that made this a reality,” said principal investigator Cristina Thomas of Northern Arizona University in Flagstaff, Arizona. “We have been planning these observations for years, then in detail for weeks, and I’m tremendously happy this has come to fruition.”

Scientists also plan to observe the asteroid system in the coming months using Webb’s Mid-Infrared Instrument (MIRI) and Webb’s Near-Infrared Spectrograph (NIRSpec). Spectroscopic data will provide researchers with insight into the asteroid’s chemical composition.

Webb observed the impact over five hours total and captured 10 images. The data was collected as part of Webb’s Cycle 1 Guaranteed Time Observation Program 1245 led by Heidi Hammel of the Association of Universities for Research in Astronomy (AURA).

Hubble Images Show Movement of Ejecta After Impact

Hubble also captured observations of the binary system ahead of the impact, then again 15 minutes after DART hit the surface of Dimorphos. Images from Hubble’s Wide Field Camera 3 show the impact in visible light. Ejecta from the impact appear as rays stretching out from the body of the asteroid. The bolder, fanned-out spike of ejecta to the left of the asteroid is in the general direction from which DART approached.

Some of the rays appear to be curved slightly, but astronomers need to take a closer look to determine what this could mean. In the Hubble images, astronomers estimate that the brightness of the system increased by three times after impact, and saw that brightness hold steady, even eight hours after impact.

Hubble plans to monitor the Didymos-Dimorphos system 10 more times over the next three weeks. These regular, relatively long-term observations as the ejecta cloud expands and fades over time will paint a more complete picture of the cloud’s expansion from the ejection to its disappearance.

“When I saw the data, I was literally speechless, stunned by the amazing detail of the ejecta that Hubble captured,” said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona, who led the Hubble observations. “I feel lucky to witness this moment and be part of the team that made this happen.”

Hubble captured 45 images in the time immediately before and following DART’s impact with Dimorphos. The Hubble data was collected as part of Cycle 29 General Observers Program 16674.

“This is an unprecedented view of an unprecedented event,” summarized Andy Rivkin, DART investigation team lead of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

University of Adelaide research shows that in cases where biodiversity metrics show no change or little change, there may still be reorganisation of ecological communities in our oceans.

“The belief that climate change will alter global marine biodiversity is one of the most widely accepted,” said Professor Ivan Nagelkerken from the University of Adelaide’s Environment Institute and Southern Seas Ecology Laboratories.

“Commonly used biodiversity measures don’t pick up reorganisation of marine communities due to ocean acidification because new species replace species that are lost.

“Little or no biodiversity change is detected when one community of marine species is replaced by another even under significant habitat loss.”

The team looked at research undertaken into how species communities located around undersea volcanic CO₂ vents and in laboratory mesocosms respond to changes in climate. They reviewed 58 research studies that examined communities in different types of temperate reefs, coral reefs and seagrass beds, and 23 studies carried out in outdoor experimental environments or laboratories.

Climate change due to human activity has a direct impact on marine species. It alters their abundance, diversity, distribution, feeding patterns, development and breeding, and the relationships between species are affected.

The University of Adelaide’s Professor Sean Connell, who is also from the Environment Institute and Southern Seas Ecology Laboratories, co-authored the study.

“Experiments done in the laboratory are weak in detecting biodiversity change, so natural systems experiencing advanced ocean acidification are emerging as an innovative way of studying biodiversity responses,” he said.

“No ecological study, whether in the laboratory or field, can fully replicate the complex ecological interactions that exist in nature across the time and spatial scales of relevance to climate change.”

Rising sea temperatures are causing lasting damage to many of the world’s significant ecosystems, including coral reefs and kelp forests.

“Future projections of ecosystem change and stability will be more meaningful if they focus on detections of species replacements and changes to the abundance of species rather than testing for signs of habitat loss or biodiversity loss per se,” said Professor Nagelkerken.

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Materials provided by University of Adelaide. Original written by Crispin Savage. Note: Content may be edited for style and length.

Cell biologists are very interested in actin, because actin — a protein of which we produce more than 100 kilograms in our lifetime — is a main component of the cell skeleton and one of the most abundant molecules in a cell. Large quantities can be found in every cell type and it has many purposes: it gives shape to the cell and makes it firmer, it plays an important role in cell division, it can propel cells forward, and provides strength to our muscles. People with faulty actin proteins often suffer from muscle disease. Much is known about the function of actin, but how the final form of this important protein is made and which gene is behind it? “We didn’t know,” says Brummelkamp, whose mission is to find out the function of our genes.

Genetics in haploid human cells

Brummelkamp has developed a number of unique methods for this purpose over the course of his career, which allowed him to be the first to inactivate genes on a large scale for his genetics research in human cells twenty years ago. “You can’t crossbreed people like fruit flies, and see what happens.” Since 2009, Brummelkamp and his team have been using haploid cells — cells containing only one copy of each gene instead of two (one from your father and one from your mother). While this combination of two genes forms the basis of our entire existence, it also creates unwanted noise when conducting a genetics experiment because mutations usually occur in just one version of a gene (the one from your father, for example) and not the other.

Multi-purpose method for genetics in human cells

Together with other researchers, Brummelkamp uses this multi-purpose method to find the genetic causes of particular conditions. He has already shown how the Ebola virus and a number of other viruses, as well as certain forms of chemotherapy, manage to enter a cell. He also investigated why cancer cells are resistant to certain types of therapy and discovered a protein found in cancer cells that acts as a brake on the immune system. This time he went looking for a gene that matures actin — and as a result, the skeleton of the cell.

In search of scissors

Before a protein is completely “finished” — or mature, as the researchers describe it in Science — and can fully perform its function in the cell, it usually has to be stripped of a specific amino acid first. This amino acid is then cut from a protein by a pair of molecular scissors. This is also what occurs with actin. It was known on which side of the actin the relevant amino acid is cut off. However, no one managed to find the enzyme that acts as scissors in this process.

Peter Haahr, postdoc in Brummelkamp’s group, worked on the following experiment: first he caused random mutations (mistakes) in random haploid cells. Then he selected the cells containing the immature actin by adding a fluorescently labeled antibody to his cells that fit in the exact spot where the amino acid is cut off. As a third and final step, he investigated which gene mutated after this process.

They called it ‘ACTMAP’

Then came the “eureka”-moment: Haahr had traced down the molecular scissors that cut the essential amino acid from actin. Those scissors turned out to be controlled by a gene with a previously unknown function; one no researcher had ever worked with. This means that the researchers were able to name the gene themselves, and they settled on ACTMAP (ACTin MAturation Protease).

To test whether a lack of ACTMAP leads to issues in living things, they switched off the gene in mice. They observed that the actin in the cell skeleton of these mice remained unfinished, as expected. They were surprised to find that that the mice did stay alive, but suffered from muscle weakness. The researchers conducted this research together with scientists from the VU Amsterdam.

More scissors found in the skeleton of the cell

ACTMAP is not the first mystery gene discovered by Brummelkamp that plays a role in our cell skeleton function. Using the same method, his group has been able to detect three unknown molecular scissors over recent years that cut an amino acid from tubulin, the other main component of the cell skeleton. These scissors allow tubulin to perform its dynamic functions properly inside the cell. The last scissors (MATCAP) were discovered and described in Science this year. Through this earlier work on the cell skeleton, Brummelkamp managed to arrive at actin.

Mission: mapping out all 23,000 genes

“Unfortunately, our new discovery about actin doesn’t tell us how to cure certain muscular conditions,” says Thijn Brummelkamp. “But we have provided new fundamental knowledge about the cell skeleton that may be useful to others later.” Moreover, Brummelkamp, whose mission is to be able to map out the function of all of our 23,000 genes one day, can tick another new gene off his gigantic list. After all, we don’t know what half of our genes do, which means that we cannot intervene when something goes wrong.

“Using sea-surface-height observations from satellites in the way we have independently verifies observations of Arctic and Greenland ice-mass loss and allows us to tease apart contributions to global sea-level rise from individual ice sheets and glacier systems,” said Sophie Coulson, a postdoctoral researcher in fluid dynamics and geophysics at Los Alamos National Laboratory. Coulson is lead author of a paper in the journal Scienceon detecting the “fingerprint” of sea-level change attributable to the melting of the Greenland ice sheet. “Accurately predicting regional patterns of sea-level change is absolutely central to understanding the impacts of future climate change and forecasting hazards.”

Theoretical models and computer simulations can predict sea level changes as ice sheets and glaciers melt.

“As this melting continues, and the water is redistributed around the global oceans, sea level does not rise uniformly,” Coulson said. “And since every glacier and ice sheet has a unique pattern of sea-level change, these patterns have come to be known as sea-level fingerprints. But despite over half a century of research, these fingerprints have never been unambiguously detected.”

Coulson’s search focused on satellite observations of sea-surface height in the oceans surrounding the Greenland ice sheet over the last three decades. The dominant effect in this region is that as the Greenland ice sheet loses mass, it exerts less gravitational attraction on water in the open ocean and so water migrates away from the ice sheet. This results in a lowering of sea level near Greenland, but progressively higher levels of sea-level rise outside the region.

“We predicted what the pattern of sea-level change would be around Greenland using new estimates of ice melting in the area,” Coulson said. “When we then compared this pattern to satellite observations of sea-level change the fit was remarkable. It was an incredible eureka moment for us when the team saw it — ‘there it is, the sea-level fingerprint!'”

Detection of the patterns has historically been hindered by the lack of sea-surface-height measurements around polar ice sheets and the variability of shorter-timescale processes, such as changing currents and ocean density. The research team on the Science paper took advantage of processed satellite observations that extend to much higher latitudes than previously possible, where the fingerprint signal is the largest. The team processed this satellite data using a powerful new technique to remove the variability due to ocean dynamics.

The new study confirms the accuracy of the geophysical predictions of sea-level change and adds confidence to projections of sea level rise across the next decades and century. As Coulson says, “It’s a powerful and sensitive approach to monitoring ice sheets and glaciers in our warming world.”

Sophie Coulson’s work on this research was supported by a Los Alamos National Laboratory Director’s Postdoctoral Fellowship.

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Materials provided by DOE/Los Alamos National Laboratory. Note: Content may be edited for style and length.

CSHL Associate Professor Florin Albeanu and Assistant Professor Arkarup Banerjee discovered tufted cells are better at recognizing smells than mitral cells. They’ve found tufted cells are essential to one of two parallel neural circuit loops that help the brain process different odor features. The findings help explain how the brain takes in sensory information that influences behavior and emotions.

The researchers exposed mice to various odors, from fresh mint to sweet bananas, at different concentrations. They simultaneously tracked the neural activity of the two cell types and found tufted cells outperformed mitral cells. They were faster and better at distinguishing smells. They also captured a wider range of concentrations. While this illuminated a new role for tufted cells, it also led to a new unanswered question. “If tufted cells are actually better at recognizing odors, what then, is the function of mitral cells?” said Albeanu.

Albeanu and Banerjee think mitral cells enhance important smells. They are part of a neural feedback loop that may help an animal prioritize, for example, the smell of food or a predator. In contrast, the tufted cells are part of a second feedback loop that helps process smell intensity and identity. This can guide animals locating odors in the environment. Banerjee explains:

“If you can’t tell whether it’s high [intensity] versus low [intensity], then you can’t track an odor. There’s no way to know that you’re actually getting closer to the odor source if you can’t tell the difference.”

The two neural circuit loops offer novel explanations for how the brain processes sensory information. Going forward, the new genetic and optical imaging tools used by the CSHL team, that include postdoc Honggoo Chae and graduate student Marie Dussauze, can uncover more undervalued neurons involved in sensory processing.

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Materials provided by Cold Spring Harbor Laboratory. Original written by Luis Sandoval. Note: Content may be edited for style and length.