Month: June 2021

INSTITUTE OF ASTROPHYSICS OF THE CANARY ISLANDS (IAC)

Research news

PICTURE: ARTISTIC COMPOSITION OF A SUPERMASSIVE BLACK HOLE THAT REGULATES THE DEVELOPMENT OF ITS ENVIRONMENT. Show more CREDIT: GABRIEL PÉREZ DÍAZ, SMM (IAC) AND DYLAN NELSON (ILLUSTRIS-TNG).

At the heart of almost every sufficiently massive galaxy is a black hole whose gravitational field, although very intense, only affects a small area around the center of the galaxy. Although these objects are thousands of millions of times smaller than their host galaxies, our current view is that the universe can only be understood if the evolution of the galaxies is regulated by the activity of these black holes, because without them the observed properties of the galaxies cannot be be explained.

Theoretical predictions suggest that as these black holes grow, they generate enough energy to heat up and expel the gas in galaxies over great distances. Observing and describing the mechanism by which this energy interacts with galaxies and changes their evolution is therefore a fundamental question in astrophysics today.

With this aim in mind, a study led by Ignacio Martín Navarro, a researcher at the Instituto de Astrofísica de Canarias (IAC), went a step further and sought to investigate whether there was any matter and energy emitted by these black holes can change the development not only of the host galaxy, but also of the satellite galaxies surrounding it at even greater distances. To do this, the team used the Sloan Digital Sky Survey, which allowed them to analyze the properties of galaxies in thousands of groups and clusters. The conclusions of this study, which began during Ignacio’s stay at the Max Planck Institute for Astrophysics, are published today in Nature magazine.

“Surprisingly, we found that the satellite galaxies formed more or fewer stars depending on their orientation in relation to the central galaxy,” explains Annalisa Pillepich, researcher at the Max Planck Institute for Astronomy (MPIA, Germany) and co-author of the article. To explain this geometric effect on the properties of the satellite galaxies, the researchers used a cosmological simulation of the universe called Illustris-TNG, the code of which contains a specific handling of the interaction between central black holes and their host galaxies. “As with the observations, the Illustris TNG simulation shows a significant modulation of the star formation rate in satellite galaxies as a function of their position in relation to the central galaxy,” she adds.

This finding is doubly important as it supports the observational assumption that central black holes play an important role in regulating the evolution of galaxies, which is a fundamental feature of our current understanding of the universe. Still, this hypothesis is constantly being challenged as it is difficult to measure the possible effect of black holes in real galaxies rather than just considering theoretical implications.

So these results suggest that there is a special coupling between the black holes and their galaxies, through which they can eject matter at great distances from the galactic centers and even affect the evolution of other nearby galaxies. “So we can not only observe the effects of central black holes on the development of galaxies, but our analysis also opens the way to understanding the details of the interaction,” explains Ignacio Martín Navarro, first author of the article.

“This work was made possible by the collaboration between two communities: the observers and the theorists who, in the field of extragalactic astrophysics, find that cosmological simulations are a useful tool for understanding how the universe is behaving,” he concludes.

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Article: Ignacio Martín Navarro, Annalisa Pillepich, et al. “Anisotropic satellite extinction, modulated by the activity of black holes”. Nature, June 10, 2021. DOI: 10.1038 / s41586-021-03545-9

From EurekAlert!

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By the end of this decade, several space agencies plan to send astronauts to the moon for the first time since the Apollo era. But while Apollo was a “footprint and flag” affair, the current proposals for exploring the moon call for the creation of an infrastructure that allows for a permanent human presence there. In addition to NASA’s Artemis program, ESA is also working on a plan to create an “International Moon Village”.

For years, ESA has been publishing teasers of what this “successor to the International Space Station” (ISS) might look like, the latest of which can be seen in the La Biennale di Venezia museum in Venice. As part of the 17th International Architecture Exhibition, the architecture firm Skidmore, Owings & Merrill (SOM) presented its design (with technical support from ESA) for a semi-inflatable lunar habitat that could enable long-term lunar colonization.

While the theme of this year’s architecture exhibition, which runs from May 22 to November 11, is “How will we live together?”. This is broken down into five scales, consisting of “Among different beings”, “As new households”, “As emerging communities”, “Across borders” and “As one planet”. The SOM installation (which spans some of the scales) is titled “Life Beyond Earth” and envisions how people can live sustainably in the hostile environment of space.

The SOM installation consists of two large format models of the habitat and a film (see below) that shows how a habitat module is delivered to the moon and integrated with others to form a fully functional “village”. The SOM design is based on a semi-inflatable shell structure that offers the highest possible volume-to-mass ratio (and can be launched to the moon at a lower cost).

When they reach the surface of the moon, the modules are inflated and almost double their original volume. The interior of each module consists of a four-story floor-to-ceiling ceiling environment with interior lighting and reconfigurable functions. This enables crews to take advantage of lunar gravity (16.5% of Earth’s gravity) by effortlessly ascending and descending between floors (which is aided by poles and other simple tools).

The video also shows the selected location for the future lunar village, which is within the edge of a massive lunar impact crater. This is Shackleton Crater, which is located in the South Pole Aitken Basin and measures 21 km (13 miles) in diameter and 4 km (2.5 miles) deep. This location is considered an ideal location for a lunar base, as the ground is permanently shaded and therefore immune to the extreme temperature fluctuations on the lunar surface.

The ESA moon base shows its position in the Shackleton crater. Photo credit: Skidmore, Owings & Merrill / ESA

Since the moon is connected to the earth by the tides (with one side constantly facing it), the lunar surface has a day-night cycle that lasts about a month on earth – an average of 29 days, 12 hours, 44 minutes , and 3 seconds. During a two-week “lunar day”, surface temperatures away from the poles can reach up to 390 K (117 ° C; 243 ° F) and up to 100 K (-173 ° C; -280 ° F.)) During a “moon night”.

In permanently shadowed craters, temperatures are relatively stable at 60 (-213 ° C; -352 ° F) to 80 K (-193 ° C; -316 ° F), while the rest of the polar surface receives near-continuous sunlight. Solar systems installed directly behind it along the edge could use this exposure to generate a constant flow of electricity. In addition, Shackleton and other impact craters in the southern polar region have abundant water ice on their permanently shaded floors.

Another benefit of building in this region is the constant view of the earth. This is another advantage of its location in the polar regions of the moon and the nature of its orbit with the earth. While it is necessary to create habitats that look up to the surface and provide a sense of connection with the local environment, the ability to see the earth will allow future people living outside the world to connect with their home to feel.

The interior of the lunar village shows where plants are grown for oxygen and food. Photo credit: Skidmore, Owings & Merrill / ESA

It would also give everyone who lives and works on the lunar surface the opportunity to experience the “overview effect” whenever they feel like going on a moonwalk! As Frank White, a “space philosopher” who coined the term, described it in his 1987 book of the same name, the term describes the shift in consciousness that occurs when one looks at the earth from space – generally as the earth as one , valuable system that is not subject to arbitrary limits.

Other possible means of building a lunar base are to combine inflatable structures and 3D printer robots to create the outer shell of a base from lunar regolith – a process known as In-Situ Resource Utilization (ISRU). This can be done with an aggregate of regolith and binders (i.e. “lunacrete”) and molten ceramic, which is made by bombarding regolith with microwaves (also known as “sintering”) and 3D printing the hot material onto the surface where it is hardens.

In addition to the lunar village proposed by ESA, these techniques could be used to establish Artemis base camp, as well as a Chinese and Russian lunar base. Other pieces of NASA’s Artemis mission architecture are shown in the video, such as the Lunar Gateway and the Multi-Mission Space Exploration Vehicle (MMSEV) – a next-generation manned surface vehicle NASA is developing for the Moon and Mars.

Astronauts on an EVA outside the lunar village. Photo credit: Skidmore, Owings & Merrill / ESA

This and the next decade will be a very interesting and exciting time as several space agencies and commercial partners will create the necessary infrastructure to ensure that humans can continue to explore, live and work on the moon in the future. In the midst of it all, the message of the “Artemis Generation” is clear: “We’re going back to the moon. And this time we stay! “

Further reading: ESA

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Reposted from NOT A LOT OF PEOPLE KNOW THAT

By Paul Homewood

Ken Gregory has sent me his latest paper on the Social Cost of Carbon.

If he is correct, it upends all of the arguments for spending trillions of dollars on a non existent problem:

Social Cost (Benefit) of Carbon Dioxide from FUND

with Corrected Temperatures, Energy and CO2 Fertilization

By Ken Gregory, P.Eng. May 26, 2021

Summary

Climate policies such as carbon taxes are set by governments using social cost of carbon (SCC) values calculated by economic computer programs called integrated assessment models (IAM). FUND is the most complex of the IAMs which links emissions scenarios and models of economics, climate and impacts for 16 world regions. Unfortunately, the climate component of FUND that determines temperature is flawed as it assumes that the deep oceans are instantly in temperature equilibrium with the atmosphere, without any time delay, when the equilibrium climate sensitivity (ECS) is 1.5 °C or less. The FUND model runs too warm compared to climate models.

The ESC can only be estimated using the energy balance method that compares the climate forcings to historical temperature records. The paper Lewis & Curry 2018 presents estimates of ECS with uncertainty analysis. The analysis was deficient in that the natural climate change was not considered and no correction was applied to remove the urban heat island effect from the temperature record. Making these adjustments, the likely range of ECS based on energy balance calculations using actual historical temperatures is 0.76 – 1.39 °C with a best estimate of 1.04 °C.

The energy impact components for space heating and cooling expenditures of FUND are very flawed. The change of expenditures with temperatures does not correspond to expenditure data published for the USA states. A paper by Peter Lang and me shows that a 3 °C temperature rise would decrease energy expenditures in the USA by 0.07% of gross domestic product (GDP) but FUND projects an increase of expenditures of 0.80% of GDP with non-temperature drivers held constant. A study by Dayaratna, McKitrick and Michaels (D, M & M 2020) of the CO2 fertilization effect and the FUND agricultural component shows that the FUND CO2 fertilization effect should be increased by 30%.

I have created a modified version of FUND which incorporates a 2-box ocean climate model that is tuned to closely match the temperature profile of climate models. I have replaced the flawed space heating and cooling components with new components to match the empirical heating and cooling USA data and increased the FUND CO2 fertilization effect by 30%. The social net benefit of CO2 emissions is calculated using the ECS probability distribution. The results show the net benefits of CO2 emissions are 11.74 and 8.41 US$/tCO2 at 3% and 5% discount rate, respectively.

Agriculture dominates the SCC values which are greater than 100% of the net benefits of CO2 emissions. The mainstream media is fixated on storms and sea level rise which are insignificant. The data show that climate change with the CO2 fertilization effect is quite beneficial, so policies costing trillions of dollars to reduce CO2 emissions are misguided. See the report here.

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