In space, there are clouds that contain gas and dust ejected from stars. Our solar system was formed 4.6 billion years ago from such a molecular cloud. Most of these dust grains were destroyed during solar system formation. However, a very small amount of the grains survived and remained intact in primitive meteorites. They are called presolar grains because they predate the solar system. I am a scientist who studies the early solar system and beyond, focusing mainly on presolar grains.
The picture is an image of such a grain taken by a scanning electron microscope. This grain is silicon carbide (SiC). The scale bar is 1 micron, or one millionth of a meter (39.37 inches). The grain was extracted from the Murchison meteorite that fell in Australia in 1969.
Scientists have investigated physical properties of the grain to determine its origin. Carbon has two stable isotopes, ¹²C and ¹³C, whose weights are slightly different from one another. The ratio between these isotopes is almost unchanged by processes taking place in the solar system such as evaporation and condensation. In contrast, nucleosynthetic processes in stars cause ¹²C/¹³C ratios to vary from 1 to over 200,000.
If this grain had originated within the solar system, its ¹²C/¹³C ratio would be 89. The ¹²C/¹³C ratio of the grain in this picture is about 55.1, which attests to its stellar origin. Together with other information about the grain, the ratio tells us that this grain formed in a type of star called an asymptotic giant branch star. The star was at the end of its life cycle when it profusely produced and expelled dust into space more than 4.6 billion years ago.
Scientists have found other types of presolar grains in meteorites, including diamond, graphite, oxides and silicates. Presolar grains like the one in the picture help researchers understand nucleosynthesis in stars, mixing of different zones in stars and stellar ejecta, and how abundances of elements and their isotopes change with time in the galaxy.
theconversation.com – Anthony W. Orlando, Assistant Professor of Finance, Real Estate and Law, California State Polytechnic University, Pomona – 2025-01-14 13:02:00
The Los Angeles housing market is poorly equipped for this crisis. It is already one of the nation’s most expensive markets to buyor rent a place to live, largely due to a significant and growing shortage of affordable housing. That shortage will become only more dire with the destruction of so many fire-ravaged buildings.
For the past two years, I have been studying the effects of natural disasters like this one on rental housing markets. As a professor of real estate, I have analyzed the question from a distance, sifting through data.
This time, however, as a resident of Pasadena, I have seen the carnage up close. I watched the Eaton Fire spread across the mountains from my back porch. I helped friends evacuate before their neighborhood was consumed in flames. Now, they’re sitting at my dining table as they process what they’ve lost and search for a new place to live.
Unfortunately, from my research, I have no doubts about what comes next.
Why disasters drive up rents
Scarcity is the enemy of affordability. This is one of the central tenets of economics. When too many people chase too few goods, prices rise.
So, you might expect that a natural disaster, which destroys housing and inundates the remaining units with new renters, would drive up rents, at least in the short run.
That is exactly what my research has found – but it’s not just the short run.
Two years ago, I worked with a team of researchers to prepare a report for the Brookings Institution, where we compiled a database of natural disasters across a variety of major markets throughout the country from 2000 to 2020. We measured the change in rents in places such as Atlanta, Detroit, Miami and San Francisco that landlords were asking for apartments in disaster-impacted neighborhoods. We then compared those cities with similar neighborhoods that weren’t impacted by the disasters.
We found that natural disasters increased rents during those two decades by 4% to 6%. That means rents were at least 4% higher than they would have been in the absence of the disaster.
These rent hikes were especially clear and pernicious after wildfires in California.
These weren’t just short-term effects. It took 18 months for the full effects to be felt in the market, and they never fully went away. Even four years after the disaster, renters were still paying 2% to 3% more than they would have been without the disaster.
In short, we found that disasters permanently change rental housing markets. They eliminate older, affordable housing, allowing developers to build newer, higher-end and even luxury housing in its place. Those changes drive up insurance costs, and the disasters motivate cities to adopt stricter building codes that in turn add to construction costs for the sake of weathering future disasters better.
How much rents increase, however, depends on how communities and the authorities respond to the disaster.
Federal aid can slow the growth of rents
We found that rents did not grow as fast when the government stepped in to help.
Specifically, we investigated markets where Congress had used the Community Development Block Grant Disaster Recovery – CDBG-DR – program, providing grants through the Department of Housing and Urban Development. This federal funding typically comes with strings attached and “rental requirements” often mandating that a significant portion of the money be used to build affordable housing.
At least one of these disaster relief grants was issued every year from 2003 to 2020. In some years, Congress allocated as many as 27 different grants across the country to different disaster-impacted areas.
In these markets, we found that rents still rose after disasters – but at a significantly slower pace than in the markets where Congress didn’t send these disaster relief funds.
We dug deeper into several case studies in 2024 to understand why the CDBG-DR program is associated with lower rent hikes over the long run. In this new study, we found that housing markets that benefited from these disaster relief grants were able to build more rental units, easing the housing shortage. They improved affordability by tackling the scarcity problem directly.
Rental units were the key to solving the rent crisis. These cities, where affordability was better post-disaster, didn’t build more single-family homes than the other cities. They built more apartment units.
In these markets, these disaster relief grants saved the average renter between $780 and $1,080 in annual housing costs in 2023.
We believe that this finding shows why it is important not only to rebuild the houses destroyed in disasters like the Los Angeles fires but also to create new rental opportunities in all kinds of housing.
Hope in the aftermath
Here in Los Angeles, the clock is already ticking.
Fortunately, there are government policiesand programsthat can help Angelenos find shelter today and that may help the Los Angeles housing market not get even less affordable tomorrow.
Today, the United States is navigating an increasingly unsettled world. The positions advising the president on national security are as important as ever. One such position, the director of the Central Intelligence Agency, is key to providing the president and Cabinet with timely intelligence and analysis.
So, what is the job of director of the CIA? What role does the director play in U.S. national security? How has the position changed over time?
The CIA’s role in national security
The CIA director leads the government agency responsible for conducting espionage and covert action. The CIA director is a Cabinet level position but reports to the director of national intelligence.
The CIA was established by the National Security Act of 1947 as America’s premiere civilian-led foreign intelligence agency. The agency carries out espionage and covert action exclusively outside the U.S.
The CIA is organized into five directorates – analysis, operations, science and technology, digital innovation, and support – and 11 regional and topical mission centers. The number of CIA employees is classified.
Espionage activities include the use of spies tasked with collecting useful information from influential people in countries around the world. This information, referred to as human intelligence, often provides depth and context about threats posed to the U.S.
In addition to collecting intelligence, the CIA analyzes and interprets it. The agency employees thousands of expert analysts who assess the information’s implications for U.S. national security. It is this in-depth analysis that is often presented to the president and Cabinet to inform their decision-making.
Covert action is an activity intended to influence political, economic or military conditions abroad without the role of the U.S. being apparent. Such actions include programs such as disinformation campaigns, counterterrorism operations and military raids such as the one used to kill 9/11 attack organizer Osama bin Laden.
Effective espionage and covert action are likely to prove crucial for blunting threats that nations such as China, Russia, Iran and North Korea pose to the U.S. They will be key to monitoring the activities of these nations and enabling the director to deliver timely and valuable analysis to the president.
CIA director’s changed role
During the Cold War, the director of central intelligence had autonomy to conduct these covert actions with limited oversight. The position was extremely powerful at the time because the director was in charge of overseeing all U.S. intelligence activities, not just those of the CIA. This left the director of the CIA as the primary voice on intelligence matters to the president.
Since significant reform of the U.S. intelligence community in 2005 in response to the failure to prevent the 9/11 attacks, the role of the CIA director has changed. The most significant of these changes is that the CIA director no longer manages all U.S. intelligence. The reforms gave that responsibility to the more independent director of national intelligence.
The reform also saw the CIA director’s influence diminished because the position is no longer the primary intelligence adviser to the president. This has created tension between the two positions at times, with the CIA maintaining a high degree of independence from even the director of national intelligence.
While there is more oversight of the CIA today from Congress and the director of national intelligence, the agency remains relatively independent in conducting espionage and covert action. These include covert actions during the Syrian civil war and during Russia’s invasion of Ukraine.
Another change has been the increased size of the intelligence community. The CIA today is only part of a much larger group of intelligence agencies. These include the Federal Bureau of Investigation, the Defense Intelligence Agency, the National Security Agency and more specialized agencies like the National Geospatial-Intelligence Agency.
In spite of this more capable and larger intelligence community, the CIA remains the premiere U.S. intelligence agency. This ensures that the CIA director will remain a key player in any presidential administration. The director possesses an immense responsibility to protect the U.S. from foreign threats.
Although the CIA director’s role has changed over time, what remains clear is its central importance to the success of U.S. national security efforts. This has become only more apparent given the increasing turbulence in world affairs.
This story is part of a series of profiles of Cabinet and high-level administration positions.
Governments often condemn terrorist groups in this way, as well as making threats and engaging in what we call “verbal attacks.”
But such an approach may be counterproductive; extremist groups tend to respond to such comments by ratcheting up violence against civilians. That’s what we found when we analyzed six years of data on incidents of terrorist violence and their proximity to government denunciations.
Our study focused primarily on the Islamic State group.
Although it has declined substantially since then, the group remains the world’s deadliest terror organization – responsible for nearly 2,000 deaths in 2023.
The rapid metastasis of the Islamic State group – it has affiliates across the Middle East, North Africa and South Asia – combined with the extreme brutality of its tactics, triggered waves of condemnations by foreign governments. Former U.S. president Barack Obama initially referred to the Islamic State group as the “JV team” in 2014, implying that the group was not as formidable an opponent as more established groups like al-Qaida. A year later, he vowed to “destroy” the group.
Our motivating research question is whether these and similar statements affect terrorists’ behavior.
But when extremist groups commit terror attacks, they always have an audience in mind. And the Islamic State group closely monitors how governments respond to its actions.
Terrorist groups use attacks on civilians to illustrate the extreme measures they are willing to take to achieve their goals. Our research suggests that when governments denounce terrorists, reject their demands or make retaliatory threats, targeted groups infer that they are not being taken seriously. As a result, they commit further atrocities against civilians, with the intent of signaling their intentions and capabilities even more forcefully.
To confirm this, we used a large-scale machine-coded dataset known as the Integrated Crisis Early Warning System to extract daily data on all events involving the Islamic State group for the period 2014 to 2020. We then employed a coding system known as CAMEO to identify events where governments threatened, denounced or otherwise verbally attacked the group.
We found that when governments initiated any form of verbal attack against the organization, the Islamic State group responded by targeting civilians, typically within two days of a verbal attack.
Our model showed that every three verbal attacks by governments led to an additional, otherwise unexpected attack by the Islamic State group on civilians. These attacks averaged over six deaths per attack, so the humanitarian consequences of this effect are substantial.
Why it matters
Government leaders face enormous pressures to address national security threats, and terrorism is a powerful source of anxiety for citizens.
As such, publicly threatening or denouncing an organization offers a tempting alternative strategy. But there has been little research into how government leaders’ words might backfire, encouraging extremists to attack civilians.
At the same time, although the Islamic State group has diminished greatly in capacity, transnational terrorism continues to flourish. And the resurgence of the Islamic State group remains a threat to security in the Middle East and beyond.
What still isn’t known
We extended the analysis to the terrorist groups Boko Haram in Nigeria and Al-Qaida in Iraq, and we found similar results. But further research is needed to determine whether this pattern holds for terrorist groups in general.
Our theory argues that extremists respond so strongly to verbal attacks because they view those remarks as questioning the group’s credibility – a phenomenon we refer to as a “credibility deficit.”
But terrorists have many motivations, including the desire to control territory and repress dissent. We don’t yet know the magnitude of these influences relative to credibility.
The Research Brief is a short take on interesting academic work.