Science
Martin Karplus, Chemist Who Made Early Computers a Tool, Dies at 94
Martin Karplus, a Nobel Prize-winning theoretical chemist who used computers to model how complex systems change during chemical reactions, a process that has led to advances in the understanding of biological processes, died on Dec. 28 at his home in Cambridge, Mass. He was 94.
His wife, Marci Karplus, said he died while recovering from a fall in which he broke a femur.
Over his long career, Dr. Karplus had crossed paths with some of the most important scientists of the 20th century, including Linus Pauling and J. Robert Oppenheimer.
Scientists can control the chemicals in a reaction, and they can measure and evaluate the results, but what happens in between is a mystery.
As Sven Lidin, chairman of the Nobel selection committee explained when announcing the 2013 winners in chemistry: “It’s like seeing all the actors before Hamlet and all the dead bodies after, and then you wonder what happened in the middle. And actually, there is some interesting action there, and this is what theoretical chemistry provides us with — the whole drama.”
Beginning in the 1960s, when computers were only a fraction as powerful as today’s smartphones, Dr. Karplus and his fellow Nobel laureates — Michael Levitt, originally from South Africa, and Arieh Warshel, who was born in Israel — began to build virtual models of molecules to understand what happens to them during complex reactions like photosynthesis and combustion.
The models used classical Newtonian physics to predict how multitudes of atoms and molecules move during reactions, and they used quantum physics to describe how chemical bonds are broken and formed during those reactions. This type of analysis proved particularly useful in understanding biological reactions involving enzymes, the proteins that govern chemical responses in living organisms.
There was initial resistance to the scientists’ work because it was difficult for others to accept that computer models could be accurate enough or could sufficiently account for the many variables in some reactions. But by the time the Nobel Prize was awarded in 2013, that skepticism was gone.
“Today, the computer is just as important a tool for chemists as the test tube,” the academy wrote in its announcement. “Simulations are so realistic that they predict the outcome of traditional experiments.”
At Harvard University, where Dr. Karplus spent most of his career, he and his research team in 1983 created a program for simulating molecular interaction, calling it Chemistry at Harvard Macromolecular Mechanics (CHARMM). The program is available to researchers worldwide.
In the late 1950s, Dr. Karplus made another important contribution to chemistry: He developed what is known as the Karplus equation. It makes it possible to calculate the magnitude and orientation of protons in organic compounds involved in nuclear magnetic resonance spectroscopy, allowing chemists to study the arrangements of atoms in molecules. It is now a basic part of chemistry education.
Martin Karplus was born on March 15, 1930, in Vienna into a well-off and intellectually accomplished Jewish family. He was the second son of Johann Karplus, a banker, and Isabella (Goldstern) Karplus, a hospital dietitian.
His paternal grandfather, Johann Paul Karplus, was a neurologist who discovered the functions of the hypothalamus, the crucial brain region that controls body temperature, hunger, heart rate and other vital activities. An uncle, Eduard Karplus, was an engineer and inventor. And Martin’s older brother, Robert, became a theoretical physicist at the University of California at Berkeley.
In the face of rising antisemitism in the 1930s and a few days after Nazi Germany annexed Austria in the Anschluss of March 1938, Martin, his brother, and his mother fled to Zurich and then to France, eventually arriving in Le Havre.
Martin’s father was initially imprisoned in Vienna, but he was able to join the family before they set sail for New York. They arrived on Oct. 8, 1938, and soon after moved to Newton, Mass.
At Newton High School, Martin discovered that his older brother had made such a mark there that many teachers doubted Martin’s ability to do as well, he recalled in a Nobel biography. One teacher, who was in charge of the Westinghouse Science competition, the nation’s top talent search in the sciences, told Martin that it would be a waste of his time to enter.
But he found another teacher who was willing to proctor his test for the competition. He went on to qualify as one of the country’s 40 finalists. Martin’s project on alcids, an aquatic bird, was chosen as the co-winner of the competition, after which he met President Harry S. Truman in Washington.
Accepted to Harvard University, he concentrated on chemistry and physics. As he was finishing his undergraduate degree in 1950, both the University of California at Berkeley and the California Institute of Technology, known as Caltech, accepted him for graduate studies.
Unsure where to go, he visited his brother, Robert, who by then was working at the Institute for Advanced Study in Princeton, N.J. Robert showed him around, introducing him to Albert Einstein and J. Robert Oppenheimer, who had led the Manhattan Project that developed the atomic bomb and who had become the institute’s director. Dr. Oppenheimer recommended Caltech, where he had been a professor, calling it “a shining light in a sea of darkness,” according to Dr. Karplus’s biography. Decision made.
At Caltech he focused on biophysics, joining a graduate group led by Max Delbrück, who, along with Salvador E. Luria, had proved that Darwin’s theory of evolution also applied to bacteria. They, along with Alfred D. Hersey, would be awarded the Nobel Prize in Physiology or Medicine in 1969 for their work.
As Dr. Karplus wrote in his Nobel biography, a turning point in his life came two months after he started at Caltech. Dr. Delbrück suggested that Dr. Karplus present a seminar on his intended area of research: how vision works.
He began his presentation, but after 10 minutes Dr. Delbrück interrupted him to say that he did not understand what Dr. Karplus was saying. Dr. Karplus began anew, and Dr. Delbrück interrupted again, saying he still did not understand. Dr. Karplus began again, and Dr. Delbrück interrupted a third time.
At this point, Dr. Richard Feynman, who was awarded the Nobel Prize in Physics in 1965 and who was sitting in the audience, turned around and said to Dr. Delbrück: “I can understand, Max. It is perfectly clear to me.” Dr. Delbrück turned red and stormed out. Later that day, he called Dr. Karplus to his office and told him that he could no longer work with him.
Dr. Karplus switched to chemistry.
In the chemistry department, Dr. Karplus initially worked with Prof. John Kirkwood, but then Dr. Kirkwood left for Yale University. His graduate students were given the chance to switch to working with Linus Pauling. Only Dr. Karplus accepted.
Dr. Pauling was on the short list of the greatest scientists of the 20th century. He was one of only five people to receive two Nobel Prizes: the first in 1954 for chemistry, for determining how atoms are chemically bound in molecules; and the second, the Nobel Peace Prize, in 1962, for promoting nuclear disarmament. His scientific work led to the founding of quantum chemistry and molecular biology.
Dr. Karplus’s time with Dr. Pauling proved fruitful: He finished his doctoral dissertation just before Dr. Pauling departed on a trip in late 1953. Dr. Karplus, who had received a National Science Foundation postdoctoral fellowship, then left to spend two years at Oxford University.
In 1955, he was hired by the University of Illinois, which was doing advanced work on nuclear magnetic resonance (NMR) spectroscopy. It was during his five years in Illinois that he put together his Karplus equation.
In 1960, Dr. Karplus was hired to be a researcher at the IBM Watson Scientific Laboratory and to teach at Columbia University. With access to state-of-the-art computing power, he continued his research on NMR and also began to investigate creating models to explain chemical reactions.
Dr. Karplus changed jobs again in 1966, returning to Harvard. There he started to concentrate on biological reactions, which are the most complex. The work would lead to the creation of CHARMM and to his Nobel Prize.
In the 1990s, Dr. Karplus was appointed a professor at Louis Pasteur University, later renamed the University of Strasbourg, in France. He spent the next 20 years going back and forth between there and Harvard.
Dr. Karplus met Marci Hazard at Harvard, where she has worked for 51 years. They married in 1981. His first wife was Susan Karplus; their marriage ended in divorce.
In addition to his wife, he is survived by two children from the earlier marriage, Reba and Tammy; one child from his second marriage, Mischa; and one grandchild. (Susan Karplus died in 1982. His brother, Robert, died in 1990.)
In 2020, Dr. Karplus published his autobiography, “Spinach on the Ceiling: The Multifaceted Life of a Theoretical Chemist.” The title referred to the landing spot of a launched spoonful of spinach that he had been ordered to eat as a boy.
Over his career, Dr. Karplus supervised close to 250 graduate and doctoral students, most of whom have gone on to successful academic careers. They are collectively known as Karplusians.
WASHINGTON — NASA recaptured the world’s attention with Artemis II, which took astronauts to the moon and back for the first time in half a century. But the agency’s scientific projects could again be under threat as the Trump administration makes a renewed push to drastically cut their funding — including at the Jet Propulsion Laboratory.
The cuts, proposed in the Trump administration’s 2027 budget request to Congress, would pose further challenges to the already weakened Caltech-managed lab and could be broadly damaging to American efforts to bring back new discoveries from space. They echo last year’s attempt by the administration to slash NASA funding, which Congress rejected.
Though the Artemis project is billed as laying a foundation for a crewed NASA mission to Mars, exploration of the Red Planet is among the endeavors that could be slashed. The rover currently exploring Mars’ ancient river delta and a mission to orbit Venus are among projects with JPL involvement targeted for spending cuts, according to an analysis of the NASA budget proposal by the nonprofit Planetary Society.
“This isn’t [because] they’re not producing good science anymore. There’s no rhyme or reason to it,” said Casey Dreier, chief of space policy at the Planetary Society, which led opposition to the administration’s similar effort to cut NASA funding last year.
Storm clouds hang over the Jet Propulsion Laboratory on Feb. 7, 2024.
(David McNew / Getty Images)
This time, the administration is asking Congress to cut NASA funding by 23% — including a 46% cut to its science programs, which are responsible for developing spacecraft, sending them into outer space to observe and analyzing the data they send back.
The proposal would cancel 53 science missions and reduce funding for others, according to the Planetary Society analysis. The effort to pare down NASA Science comes amid the Trump administration’s broader effort to cut scientific research across federal agencies.
The plan swiftly drew bipartisan criticism from members of Congress, who rejected the administration’s similar 2026 proposal in January. Republican Sen. Jerry Moran of Kansas, who chairs the Senate appropriations subcommittee that oversees NASA, indicated last week that he would work to fund NASA similarly for 2027, saying it would be “a mistake” not to fund science missions.
Moran plans to hold a hearing with NASA Administrator Jared Isaacman before the end of April to review the budget request, a spokesperson for his office said. The president’s budget request is an ask to Congress, which ultimately holds the power to allocate funding.
But until Congress creates its own budget, NASA will use the plan as its road map, which could slow grants and contracts. The proposal “still creates enormous chaos and uncertainty in the meantime for critical missions, the scientific workforce, and long-term research planning,” said Rep. Judy Chu (D-Monterey Park), whose district includes JPL.
A NASA spokesperson declined to comment Friday. In the budget request, Isaacman wrote that NASA was “pursuing a focused and right-sized portfolio” for its space science missions in order to align with Trump’s federal cost-cutting goals.
The budget “reinforces U.S. leadership in space science through groundbreaking missions, completed research, and next-generation observatories,” Isaacman wrote.
Jared Isaacman testifies during his confirmation hearing to be the NASA administrator in the Russell Senate Office Building on Capitol Hill on Dec. 3, 2025.
(Anna Moneymaker / Getty Images)
At JPL — which has for decades led innovation in space science and technology from its La Cañada Flintridge campus — questions had already swirled about the lab’s role in the future of NASA work.
Multiple rounds of layoffs over the last two years, the defunding of its embattled Mars Sample Return mission and a shift by the Trump administration toward lunar exploration and away from the type of scientific work that JPL executes had pushed the lab into a challenging stretch.
It has had a steady stream of employee departures in recent months, and those left have been scrambling to court outside funding from private investors, sell JPL technology to companies and increase productivity in hopes of keeping the lab afloat, according to two former staffers, who requested anonymity to describe the mood inside the lab.
“If we’re not doing science, then what are we doing?” asked one former employee, who recently left JPL after more than a decade there.
A spokesperson for the lab declined to comment, referring The Times to the budget proposal.
The NASA programs marked for cancellation or cutbacks support thousands of jobs at JPL and other centers, said Chu, who has led a push for increased funding for NASA Science. After last year’s layoffs, JPL “cannot afford to lose more of this expertise,” she said in a statement.
Among the JPL projects that appear to be slated for cancellation are two involving Venus, Dreier said. One, Veritas, is early in development and would give work to the lab for the next several years, he said.
The project would be the first U.S. mission to Venus in more than 30 years, Dreier said, and aims to make a high-resolution mapping of the planet’s surface and observe its atmosphere.
The Perseverance rover, which is on Mars collecting rock and soil samples, could face spending reductions. The budget request proposes pulling some funding from Perseverance to fund other planetary science missions and reducing “the pace of operations” for the rover.
Though how the Mars samples might get back to Earth is uncertain, the rover is still being used to explore the planet and search for evidence of whether it could have ever been habitable to life.
Researchers hope the tubes of Martian rock, soil and sediment can eventually be brought back to Earth for study. The team has about a half a dozen more sample tubes to fill and the rover is in good shape, said Jim Bell, a planetary scientist and Arizona State University professor who leads the camera team on Perseverance, which works daily with JPL.
He said NASA’s spending proposal put forth “no plan” for the future of the agency’s work.
“Are people just supposed to walk away from their consoles,” Bell asked, “and let these orbiters around other planets or rovers on other worlds — just let them die?”
The NASA document did not clearly show which programs were targeted for cuts and did not list which projects were targeted for cancellation. The Planetary Society and the American Astronomical Society each analyzed the proposal and found that dozens of projects appeared to be canceled without being named in the document.
Across NASA, other projects slated for cancellation according to the Planetary Society’s analysis include New Horizons, a spacecraft exploring the outer edge of the solar system; the Atmosphere Observing System, a planned project to collect weather, air quality and climate data; and Juno, a spacecraft studying Jupiter.
The administration’s plan also doesn’t prioritize new scientific projects, Bell said, which further jeopardizes long-term job stability and space discovery at centers like JPL.
“We’re going through this long stretch now with very few opportunities to build these spacecrafts,” Bell said. “All of the NASA centers are suffering from the lack of opportunities.”
Last year, the Trump administration proposed to slash NASA’s 2026 funding by nearly half. Instead, Congress approved funding in January that provided $24.4 billion for the agency — a cut of about 29% rather than the proposed 46%. The 2027 budget request asks for $18.8 billion.
Congress kept funding for science missions nearly steady, allocating $7.25 billion for science missions, about a 1% decrease from 2025. The administration had proposed cutting the science investment down to $3.91 billion. This time, the budget requests $3.89 billion.
Under the Trump administration, NASA has put an emphasis on moon exploration, including this month’s successful Artemis II mission. Isaacman, who defended the proposed cuts on CNN last week, touted the agency’s lunar plans, including a project to build a base on the moon.
The agency has indicated commitment to some existing science missions, including the James Webb Space Telescope, the to-be-launched Nancy Grace Roman Space Telescope, the Dragonfly spacecraft set to launch for Saturn’s moon in 2028, and other projects.
“NASA doesn’t have a topline problem, we just need to focus on executing and delivering world-changing outcomes,” Isaacman said on CNN.
Scientists have urged the government not to choose between funding science and exploration but to keep up investment in both.
“It’s ultimately kind of confusing, especially on the heels of the Artemis II mission,” said Roohi Dalal, deputy director for public policy at the American Astronomical Society. “The scientific community … is providing critical services to ensure that the astronauts are able to carry out their mission safely, and yet at the same time, they’re facing this significant cut.”
After years of heated debates among fire officials, scientists and local advocates, California’s Board of Forestry and Fire Protection released new proposed landscaping rules for fire-prone areas Friday that outline what residents can and can’t do within the first 5 feet of their homes.
Many of these proposed rules — designed to reduce the risk of a home burning down amid a wildfire — have wide support (or at least acceptance); however, the most contentious by far has been whether the state would allow healthy plants in the zone.
Many fire officials and safety advocates have essentially argued anything that can burn, will burn and have supported removing virtually anything capable of combustion from this zone within 5 feet of houses, dubbed “Zone Zero.” They point to the string of devastating urban wildfires in recent years as reason to move quickly.
Yet, researchers who study the array of benefits shade and extra foliage can bring to neighborhoods — and local advocates who are worried about the money and labor needed to comply with the regulations — have argued that this approach goes beyond what current science shows is effective. They have, instead, generally been in favor of allowing green, healthy plants within the zone.
The new draft regulations attempt to bridge the gap. They outline more stringent requirements to remove all plants in a new “Safety Zone” within a foot of the house and within a bigger buffer around potential vulnerabilities in a home’s wildfire armor, including windows that can shatter in extreme heat and wooden decks that can easily burst into flames. Everywhere else, the rules would allow residents to maintain some plants, although still with significant restrictions.
The rules generally do not require the removal of healthy trees — instead, they require giving these trees routine haircuts.
Once the state adopts a final version of the rules, homeowners would have three years to get their landscaping in order and up to five years for the bigger asks, including removing all vegetation from the Safety Zone and updating combustible fencing and sheds within 5 feet of the home. New constructions would have to comply immediately.
The rules only apply to areas with notable fire hazard, including urban areas that Cal Fire has determined have “very high” fire hazard and rural wildlands.
Officials with the Board will meet in Calabasas on Thursday from 1 p.m. to 7 p.m. to discuss the new proposal and hear from residents.
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Some L.A. residents are championing a proposed fire-safety rule, referred to as “Zone Zero,” requiring the clearance of flammable material within the first five feet of homes. Others are skeptical of its value.
Where is the Safety Zone?
The proposed Safety Zone with stricter requirements to remove all vegetation would extend 1 foot from the exterior walls of a house.
In a few areas with heightened vulnerabilities to wildfires, it extends further.
The Safety Zone covers any land under the overhang of roofs. If the overhang extends 3 feet, so does the Safety Zone in that area. It also extends 2 feet out from any windows, doors and vents, as well as 5 feet out from attached decks.
What plants would be allowed in the Safety Zone?
Generally, nothing that can burn can sit in the Safety Zone. This includes mulch, green grass, bushes and flowers.
What plants would be allowed in the rest of Zone Zero?
Homeowners can keep grasses (and other ground-covers, like moss) in this area, as long as it’s trimmed down to no taller than 3 inches.
The rules also allow small plants — from begonias to succulents — up to 18 inches tall as long as they are spaced out in groups. Residents can also keep spaced-out potted plants under this height, as long as they’re easily movable.
What about fences, trees and gates?
Any sheds or other outbuildings would need noncombustible exterior walls and roofs in Zone Zero — Safety Zone or not.
Residents would have to replace the first five feet of any combustible fencing or gates attached to their house with something made out of a noncombustible material, such as metal.
Trees generally would be allowed in Zone Zero. Homeowners would need to keep any branches one foot away from the walls, five feet above the roof and 10 feet from chimneys.
Residents would also have to remove any branches from the lower third of the tree (or up to 6 feet, whichever is shorter) to prevent fires on the ground from climbing into the canopy.
Some trees with trunks directly up against a house in this 1-foot buffer or under the roof’s overhang might need to go — since keeping branches away from the home could prove difficult (or impossible).
However, the board stressed it wants to avoid the removal of trees whenever feasible and encouraged homeowners to work with their local fire department’s inspectors to find case-by-case solutions.
What’s new and what’s not
Some of the rules discussed in Zone Zero are not new — they’ve been on the books for years, classified as requirements for Zone One, extending 30 feet from the home with generally less strict rules, and Zone Two, extending 100 feet from the house with the least strict rules.
For example, homeowners are already required to remove any dead or dying grasses, plants and trees. They also have to remove leaves, twigs and needles from gutters, and they already cannot keep exposed firewood in piles next to their house.
Residents are also already required to keep grasses shorter than 4 inches; Zone Zero lowers this by an inch.
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