Month: February 2025

This hubble picture shows a supernova called SN 2022aajn in a distant galaxy, which is about 600 million light years away with the unwieldy name WiSea J070815.11+210422.3. However, the blunt, but scientifically descriptive names are not what is important.

It is important that SN 20222aajn is a type -1a supernova, which is also referred to as the standard candle, and this image is part of a critical effort in cosmology.

Standard candles are an important part of the cosmic spacer (CDL). Astronomers use the CDL to determine precise distances to objects at extreme distances. There are different types of standard candles, although type 1A supernovae are considered the most reliable. What do all standard candles have in common?

You have a well -known intrinsic luminosity. This means that in all directions you emit the same amount of energy across all wavelengths. No matter what angle it is measured, it is the same luminosity. Our sun has intrinsic luminosity for clarity.

Astronomers compare the intrinsic luminosity of a standard candle with its apparent or observed brightness. Note the different terms “luminosity” and “brightness”. The brightness depends both on the luminosity of an object and on how this luminosity is reduced by the distance and all matter in between such as dust.

The cosmic distance manager is omnipresent in cosmology and does a good job. However, it still has some problems. The main problem has to do with calibration: How can astronomers determine what the absolute size of a candle is? How can you describe the class of objects called -1a -SN exactly so that you can recognize everyone? And how can you find enough of you in known distances to determine your intrinsic luminosity with extreme accuracy?

The cosmic distance manager begins in parallax, but has its limits. Astronomers rely on standard candles beyond Paralax. Photo credits: by ESA/Hubble, CC from 4.0, https://commons.wikimedia.org/w/index.php?curid=49212250

This Hubble picture is part of the effort. As part of an observation program, the Hubble 100 Type -1a Supernovae is observed in order to better calibrate our understanding of standard candles and their distances.

The name of the program gives a good idea of ​​its goal. It says “Reduction of Type -Ia -Supernova distortions by separating redness and intrinsic color”. Prof. Ryan Foley from the University of California in Santa Cruz is the main researcher.

If type 1a supernova were exploded in a universe without dust, the work of the astronomers would be simplified. But of course they don't. They explode in galaxies with their own dust. There can also be a lot of intergalactic dust between us and removed SN. Everything that has dust from Supernova and makes its intrinsic luminosity more difficult to determine.

Type -1a Supernovae appear in binary systems in which a star is a massive white dwarf. When his companion ages and swells, the white dwarf pulls material away from the companion to his surface. Finally, the white dwarf explodes. Photo credits: from NASA, ESA and A. Feild (STSCI); Vectorization of Chris? – http://hubblesite.org/newscenter/areleases/star/supernova/2004/34/image/d/, cc from 3.0, https://commons.wikimedia.org/w/index.php?curid= = 8666262

In observations, the redness of the dust is tangled by reducing red shift. Dust in the intergalactic medium is about as large as the wavelength of blue light. The dust absorbs and sprinkles the light from remote objects, which makes its light more red to the point in time when it reaches us. Professor Foley's observation program is an effort to “remove” intergalactic dust from our observations.

“Precise distance measurements and impartial cosmological restrictions from supernovaentype-supernovae (SNE IA) rely on a proper correction for the redness of the tavern of the tavern, which can weaken the observed SN brightness,” write foley and his fellow research. To avoid this, astronomers use a so -called “Reddening Act”. “A correction is made by comparing the observed and intrinsic color and using a reduction law to determine the extinction,” they write.

However, reduction laws are difficult to work. It's a delicate matter. “This procedure is not trivial, since the intrinsic color of an SN correlates with its luminosity in a way that can be almost distinguished from the effects of dusting in optical wavelengths,” Foey writes in the description of the observation campaign.

Astronomers use a somewhat simplified way to determine how red is a distant supernova by treating the redness from both dust and distance. “The current standard for measuring SN distances treats both idiosyncratic relationships as a single SN color law,” explains Foley. However, this leads to a distortion in measurements, since both causes probably do not contribute equally and uniformly to reddening.

“This problem is currently the greatest systematic uncertainty of SN cosmology and prevent future cosmological experiments from being achieved,” explains Foley. He also says that the mistake can be up to 6%. This is a lot in measuring objects that are hundreds of million light years away, and even much further.

How can astronomers solve this problem? By receiving better data and more of it. This is the motivation for foleys campaign that tries to avoid the problem by observing several wavelengths across the lifting.

“The way to break the degradation between SN color and dusting is to expand the observations to UV and NIR, whereby the dust and the intrinsic color dominate the observed color,” says the description of the observation program.

The researchers will try to avoid the problem of SN cosmology by examining the Hubble 100 Type Ia Supernovae in seven wavelength gangs from ultraviolet to close infrared. The leading picture is a combination of image data from four infrared wave lengths, since IR is easier to run through dust than UV or visible light. The researchers then compare the brightness of the SNE over the wavelengths and disguise the distance effect of the dusting effect.

We are used to the “Eye Candy” pictures of the hubbles that have been carrying websites and magazines for decades. You have changed our understanding of nature. But in the purely scientific side of the telescope is part of its real transformative power.

An exact cosmic spacer is an essential part of cosmology. By supporting scientists to determine the exact distances to standard candles, the Hubble helps to develop a more cosmic spacer and to pave the way for a better understanding of the universe.

Like this:

How Load…

From the emergency zone

From P Gosselin on February 2, 2025

The AMOC dispute

By Frank Bosse

(Translated from the original in climate news)

We kept her, dear reader, informed you very immediately about Amoc expressions.

Recently we also informed you about a new study in which a stable Atlantic has been found since the 1960s. It's not the only one in the recent past.

However, Prof. Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research (PIK) is a great advocate of the scenarios “The Day after Tomorrow” of a collapsing oceanic current. In June 2024 he found on X (formerly Twitter) that the AMOC reduction saga “is even more dramatic than ever”.

He himself had been responsible for a whole series of newspapers as an author or co-author, which also contributed to the scenario, and in autumn 2024 he initiated an “open letter” that spoke dramatically. We also reported about it.

Of course, the new findings could not hand it over without comment. Under the heading “The AMOC slows down, is stable, yes, no, no, yes …”, he commented on it in the blog “Real Climate”, which is led by scientists, including himself, Gavin Schmidt from NASA and others .

What he has to say can be put to the point: he defends his approaches and lists the problems of recent studies. That was to be expected. For example, he emphasizes that the new climate models (CMIP 6) hardly a connection between “its fingerprint”, the sea surface temperatures of the “heating hole” in the North Atlantic (see article here from January 17, 2025) and the actual current, but that the approximately 4 Years older are called CMIP5. He also asks whether the new ones are very reliable in this regard than the older ones. However, the efforts for the former were considerable.

He summarized:

I don't think the newer methods are more reliable than the old (his, the author). … since we have no measurements that return far enough, there is still a certain uncertainty in this regard … “

And that's the core of the matter! He does not believe in everyone, but knowledge in science would probably be more appropriate! And yes, everything is uncertain and “nothing is known precisely”.

This is also given by the well -known oceanologist Carl Wunsch in a newspaper published in August 2022:

In the coming decades, continuous monitoring of the entire coupled ocean atmospheric system will be necessary to evaluate the actual risks of the AMOC collapse, but so far There is no evidence of an upcoming or overwhelming danger. “

There are many assumptions, a lot back and forth in science, and if they are viewed in the light of the day, a lot of “faith” or “non-belief”, ie the unmistakable reference to a lack of knowledge.

So if, dear reader, a trained psychologist is again told in a news magazine that “there is an immediate danger in a few decades when things are going badly” (see here) or here: “Europe's heating is weak”: be Be careful that people do a “certainty” that simply does not exist. As I said, it is often about assumptions and faith or non-belief.

Prof. Rahmstorf also hurried to say: “The golf current system fails”, and not “the golf current system” could “somewhere, someday, somewhere, somewhere”, the northern branch, the amoc may be stable or no ((yes (((((((((( ) ((yes, according to his own blog heading).

Image: Creates with the KNMI climate researcher.

The AMOC is still in excellent health today, as the measurements from 2004 show. These are the actual “hard facts”.

We should finally stop frightening people in the Atlantic, it does not work with enlightened citizens like you, dear readers.

Like this:

How Load…

Related

Do you discover more from watts?

Subscribe to the latest posts to your e -mail.

In the more than sixty years in which scientists are involved in search of extraterrestrial intelligence (SETI), several potential examples of technological activities (“technosignatures”) were considered. While most SETI surveys have so far focused on potential radio signals from distant sources, scientists have expanded the search to search for other possible examples. This includes other forms of communication (directed energy, neutrinos, gravitational waves, etc.) and examples of megastructures (Dyson balls, Clarke bands, Nive rings, etc.)

Examples of modern search queries are Project Hephaistos, the first Swedish project dedicated to SETI. This project is named in honor of the Greek god of the smithy of Schmiede and focuses on the search for techno signatures in general instead of looking for signals that are deliberately sent to Earth. In a recently carried out work, a team led by the University of Manchester examined a Dyson Sphere candidate identified by Hephaistos. Their results confirmed that at least some of these radio sources are contaminated by an active galactic core (AGN) of the background.

The team was founded by Tongtian Ren, Ph.D. Student in astrophysics from the Jodrell Bank Center for astrophysics at the University of Manchester. He was accompanied by Prof. Michael Garrett, his superior at the University of Manchester, the suffering of the observatory and the Institute for Space Sciences and Astronomy at the University of Malta. and Andrew Siemion, Associate Research Astronom at the Berkeley Seti Research Center, the SETI Institute and the University of Oxford. The paper that describes its results recently appeared in the monthly information of the Royal Astronomical Society.

https://www.youtube.com/watch?v=QnfaQrr58sy

Dyson balls are a class of mega structures that were originally proposed by physicist Freemon Dyson, which suggested how advanced civilizations could create structures that are big enough to include their stars (thus use all of their energy). Project Hephaestos under the direction of Prof. Erik Zackrisson has published numerous articles in which possible candidates for Dyson -Sphere were examined using various methods and data sources. The fourth and recent work of the series focused on seven potential candidates (described A to G) by M-stars from a sample of 5 million, which were discovered by the GAIA observatory of the ESA.

Previously, Ren and his team examined these candidates to identify possible natural explanations. Since they examined themselves in an earlier article, these dust areas include deer disks that absorb light and resume them as infrared radiation. This will lead to an observed infrared surplus that Dyson suggested as a possible indication of his proposed mega structure. However, as you show in your latest article, the measurements of the project do not seem to resemble typical rubble slices. As Garrett explained to the universe by e -mail today:

“When I saw the original results of Project Hephaestos last year, I was skeptical – they had examined 5 million stars, and if they do this, there is a good chance that their measurements emission from background sources. You do not expect stars to show radio emission at this level, and it basically shows that radio emission probably comes from background galaxies (radio). But then you also need a special kind of galaxy, which in the optical but very bright in the infrared – the only galaxies that I knew this feature was dogs, very bright – dust -covered galaxies. “

The team was also found by another article by Jason T. Wright, a professor of astronomy and astrophysics at Penn State, the director of the Penn State Extraterrestrial Intelligence Center (PSEI), and member of the Center for Exoplanet and Restible Worlds (Cehw) inspired). In this article, Wright made the hypothesis that a real Dyson ball could possibly use radio emissions to unload waste heat. This meant that they looked at the possibility that these candidates were actually Dyson balls.

The impression of the artist of a bright, very early active galactic core. Credit: NSF/AUI/NSF NRAO/B. Saxton

As Tongtian explained, they were also inspired by earlier research from Garrett:

“Mike argued in 2015 that even in a Kardashev civilization, in which energy consumption is significantly higher than that of people on earth, their radio communication signals are too weak to determine. However, the Dyson balls could correspond to a Kardashev civilization -one that uses more energy over a billion dollar subject than a civilization of Type I. Regardless of whether the beings are located on planets or elsewhere, it may be possible to determine the use of similar electromagnetic technologies. “

In order to further examine these options, the team searched for data from the extended multi-element radio-linked interferometer knife (E-Merlin) and the European VLBI network (EVN) for data on the brightest radio source (candidate G) were preserved. To their surprise, they found that three candidates from Project Hephaesto's Radio colleagues had in the astronomy databases. As Tongtian explained, the most logical explanation is that these signals (including candidates G) can be attributed to the contamination of light radio sources – active galactic cores (AGN) – in the background:

“You shouldn't belong to civilization. Otherwise, many anomal stars would be connected as a crush in the sky, not seven. At that moment we have found that either various extraterrestrial civilizations that were hundreds of light years have all mastered the same or similar advanced radio emission technologies, or these signals come from a form of natural contamination. We preferred to assume that they were some natural objects that go beyond the Milky Way – and most likely hot dogs. “

These results effectively confirm their earlier hypothesis that at least some of the candidates identified by Hephaisto's projects are contaminated by bright radio sources, which are also very bright in the infrared wavelength. As a result, you can expect the features that Freeman Dyson predicted and expect the astronomers of Dyson balls. However, this does not exclude the remaining six candidates and underlines how important it is to thoroughly analyze every candidate with high -resolution radio observations.

The artist's impression of a Dyson ball, a mega structure associated with a civilization of Type II. Credit: sentientdevelopments.com

“We don't know that all candidates are contaminated, but some, maybe everyone, probably. I really hope that some of them are indeed good Dyson Sphere candidates, ”said Garrett. “All of this shows that when looking for candidates, a multi -wave length is required to exclude the contamination of background contamination.”

“The development of new astronomical instruments does not follow the fast update cycles of consumer electronics – it takes decades,” added Tongian. “GAIA (in 2013 and recently taken out) and Wise (introduced in 2009 and expired in 2024) provided a crucial observation window. The next generation of similar probes may not have been available for a long time, so it is unlikely that a large Dyson-Speke search program such as Project Hephaistos will be carried out again in the near future. The current seven -dyson -sphere candidates deserve carefully examined. “

Further reading: Arxiv, Mnras

Like this:

How Load…