Archiv: Natur, Wissenschaft, Raumfahrt / nature, science, space flight


13.10.2024 - 18:40 [ VideoFromSpace / Youtube ]

Replay! SpaceX launches Starship on 5th flight, booster catch successful

SpaceX launched Starship for 5th time on Oct. 13, 2024 from Starbase in south Texas. The Super Heavy booster was caught by the launch tower‘s ‚chopsticks‘ shortly after separation from Starship.

13.10.2024 - 18:34 [ CNBC ]

SpaceX’s Starship rocket completes fifth test flight, lands booster in dramatic catch

The company successfully used the arms of its launch tower to catch the rocket’s booster, a major milestone toward SpaceX’s goal of making Starship a fully reusable rocket system.
Starship continued on into space, traveling halfway around the world before splashing down in the Indian Ocean.

11.09.2024 - 02:15 [ SpaceX ]

POLARIS DAWN

During their multi-day mission to orbit, Dragon and the crew will endeavor to reach the highest Earth orbit ever flown since the Apollo program and participate in the first-ever extravehicular activity (EVA) by commercial astronauts wearing SpaceX-developed EVA suits. They will also conduct 36 research studies and experiments from 31 partner institutions designed to advance both human health on Earth and during long-duration spaceflight, and test Starlink laser-based communications in space.

11.09.2024 - 02:05 [ The Launch Pad / Youtube ]

LIVE! SpaceX Polaris Dawn Launch

Watch LIVE as SpaceX launches Polaris Dawn on its multi-day mission to orbit, which will see Dragon and its crew fly to the highest Earth orbit ever flown since the Apollo program and participate in the first-ever extravehicular activity (EVA) by commercial astronauts wearing SpaceX-developed EVA suits.

04.09.2024 - 14:20 [ frontiersin.org ]

When and Why Did Human Brains Decrease in Size? A New Change-Point Analysis and Insights From Brain Evolution in Ants

(22 October 2021)

But we also find that human brain size reduction was surprisingly recent, occurring in the last 3,000 years. Our dating does not support hypotheses concerning brain size reduction as a by-product of body size reduction, a result of a shift to an agricultural diet, or a consequence of self-domestication. We suggest our analysis supports the hypothesis that the recent decrease in brain size may instead result from the externalization of knowledge and advantages of group-level decision-making due in part to the advent of social systems of distributed cognition and the storage and sharing of information. Humans live in social groups in which multiple brains contribute to the emergence of collective intelligence. Although difficult to study in the deep history of Homo, the impacts of group size, social organization, collective intelligence and other potential selective forces on brain evolution can be elucidated using ants as models.

04.09.2024 - 13:15 [ Welt.de ]

Evolution: Das ist der Grund, wieso die Gehirne der Menschen schrumpfen

(16.11.2021)

Dass unser Gehirn langsam etwas an Masse verloren hat, ist jedoch nicht ganz so lange her: Erst vor rund 3.000 Jahren begann es zu schrumpfen.

(…)

Die Art und Weise, wie sich Individuen in einem Ameisenstaat organisieren, ähnelt unseren modernen Gesellschaftsstrukturen. Die Insekten haben, verglichen mit ihrer Körpergröße, ein Mini-Gehirn. Es ist etwa eine Million Mal kleiner als das eines Menschen – sie können aber Großes leisten. Das Prinzip dahinter ist eine Art kollektive Intelligenz. Nicht jeder muss alles können oder wissen, es gibt eine klare Aufgabenteilung.

26.04.2024 - 03:15 [ Donna Laframboise / nofrakkingconsensus.com ]

3 Things Scientists Need to Know About the IPCC

(September 1, 2015)

Now let’s take a look at point #2: Scientists are not in charge at the IPCC. Its latest report contains 60 chapters and totals more than 7,000 pages. Many good, sincere scientists toiled away on their own small portion of that enormous report. These people no doubt did their best to be honest and accurate.

But here’s the problem: almost no one will ever read that 7,000-page report.
(…)

Everyone knows this. Which is why the IPCC also produces documents in the 20 to 30-page range bearing the title: Summary for Policymakers. (…)

In fact, IPCC authors only draft these summaries. And then something incredible transpires.
A big IPCC meeting takes place. Attended by governments. Although some people in the room are scientists, the vast majority are diplomats, politicians, foreign affairs specialists, bureaucrats, and assorted other officials. These people then spend the next week re-writing the summary authored by scientists.(…)

But the bad news doesn’t stop there. There’s actually a step in the IPCC process in which the original, lengthy report gets amended so that it conforms to the politically-negotiated Summary. I am not making this up.

26.04.2024 - 02:52 [ Space.com ]

Earth got hammered by cosmic rays 41,000 years ago due to a weak magnetic field

(24 April 2024)

The question is, Do periods of low magnetosphere intensity also correlate with major upheavals in Earth‘s biosphere, the complete zone of our planet over which life exists, ranging from mountaintops to the deepest ocean trenches?

„Understanding these extreme events is important for their occurrence in the future, space climate predictions, and assessing the effects on the environment and on the Earth system,“ Sanja Panovska, a scientist at GFZ Potsdam in Germany, said in a statement.

26.04.2024 - 02:35 [ Smithsonian Magazine ]

An Evolutionary Timeline of Homo Sapiens

(February 2, 2021)

Neanderthals once stretched across Eurasia from Portugal and the British Isles to Siberia. As Homo sapiens became more prevalent across these areas the Neanderthals faded in their turn, being generally consigned to history by some 40,000 years ago. (…)

Despite the bits of genetic ancestry they contributed to living people, all of our close relatives eventually died out, leaving Homo sapiens as the only human species. Their extinctions add one more intriguing, perhaps unanswerable question to the story of our evolution—why were we the only humans to survive?

26.04.2024 - 02:05 [ Science.org ]

A global environmental crisis 42,000 years ago

(19 Feb 2021)

Do terrestrial geomagnetic field reversals have an effect on Earth‘s climate? Cooper et al. created a precisely dated radiocarbon record around the time of the Laschamps geomagnetic reversal about 41,000 years ago from the rings of New Zealand swamp kauri trees. This record reveals a substantial increase in the carbon-14 content of the atmosphere culminating during the period of weakening magnetic field strength preceding the polarity switch. The authors modeled the consequences of this event and concluded that the geomagnetic field minimum caused substantial changes in atmospheric ozone concentration that drove synchronous global climate and environmental shifts.

(…)

We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.

(…)

In addition, chronological uncertainties are complicated in radiocarbon-dated terrestrial and marine records around the Laschamps because of the elevated production of C and Be, cosmogenic radionuclides resulting from the substantial increase in high-energy cosmic radiation reaching the upper atmosphere. The high Be flux has been well described from Greenland and Antarctic ice core records (6, 20, 21), which reveal synchronous century-long Be peaks across the Laschamps that appear to reflect a series of pronounced Grand Solar Minima (GSM; prolonged periods of low solar activity similar to the Spörer and Maunder Minima: 1410 to 1540 CE and 1645 to 1715 CE), with unknown climate impacts (20, 21).

26.04.2024 - 01:50 [ ScienceNews.org ]

50 years ago, scientists named Earth’s magnetic field as a suspect in extinctions

(November 19, 2020)

Effects of Earth’s magnetic field — Science News, November 21, 1970

„Earth’s magnetic field has frequently reversed at intervals of 1 million to 100 million years. A few scientists now suspect that these reversals may have had drastic effects on terrestrial life.… During the past 2.5 million years, eight species of one-cell marine animals called Radiolaria became extinct. Six of these extinctions occurred simultaneously throughout their geographic range immediately following magnetic reversals.“

26.04.2024 - 01:30 [ PRI.org ]

Scientists link Earth’s magnetic reversals to changes in planet’s life and climate

(April 19, 2021)

The researchers examined the rings of the tree to look for changes in the amount of carbon-14 over a period of years, Gramling explains. Carbon-14 is useful not only for dating things, but because the interaction of cosmic rays with molecules in the atmosphere produces a lot of it. And when the Earth has a weakened magnetic field, more cosmic rays hit the planet.

The scientists indeed found a large spike in carbon-14 in the tree, which they could then compare with the rock record that indicated a magnetic reversal. (…)

In addition, there is the documented rise in cave art right about 41,000-42,000 years ago, Gramling points out.

26.04.2024 - 01:20 [ ScienceAlert.com ]

Earth‘s Magnetic North Pole Has Shifted So Much We‘ve Had to Update GPS

(Feb 6, 2019)

Scientists on Monday released an emergency update to the World Magnetic Model, which cellphone GPS systems and military navigators use to orient themselves.

It‘s a minor change for most of us – noticeable only to people who are attempting to navigate very precisely very close to the Arctic.

26.04.2024 - 01:14 [ MarineLink.com ]

World Magnetic Model Updated

(December 16, 2014)

Changes in the Earth‘s outer core trigger unpredictable changes in its magnetic field, an invisible force that extends from Earth‘s interior to where it meets a stream of charged particles emanating from the Sun.

26.04.2024 - 00:30 [ Geophysical Research Letters 35(16) / researchgate.net ]

Magnetic effect on CO 2 solubility in seawater: A possible link between geomagnetic field variations and climate

(August 2008)

Correlations between geomagnetic-field and climate parameters have been suggested repeatedly, but possible links are controversially discussed. Here we test if weak (Earth-strength) magnetic fields can affect climatically relevant properties of seawater. We found the solubility of air in seawater to be by 15% lower under reduced magneticfield (20 mT) compared to normal field conditions (50 mT). The magnetic-field effect on CO2 solubility is twice as large, from which we surmise that geomagnetic field variations modulate the carbon exchange between atmosphere and ocean. A 1% reduction in magnetic dipole moment may release up to ten times more CO2 from the surface ocean than is emitted by subaerial volcanism.

26.04.2024 - 00:20 [ Forbes.com ]

Is Earth’s Magnetic Shield Eroding?

(29.3.2018)

The strength of Earth’s main magnetic field is currently about 29.5 microteslas, down 5 microteslas, or 14 percent from its strength three centuries ago.

We know this. There is no question of this.

26.04.2024 - 00:00 [ Journal of Geophysical Research: Solid Earth / onlinelibrary.wiley.com ]

Possible Eoarchean Records of the Geomagnetic Field Preserved in the Isua Supracrustal Belt, Southern West Greenland

(24 April 2024)

The preservation of a temperate climate and liquid water on early Earth depends critically upon the strength of the magnetosphere (Sterenborg et al., 2011; Tarduno et al., 2014). Recent atmospheric escape models have suggested that both weak (<10 μT) and strong (>1 mT) magnetic fields could substantially enhance atmospheric escape under present-day solar wind conditions via the polar wind or cusp escape, respectively (Gronoff et al., 2020; Gunell et al., 2018; Lundin et al., 2007). During the Archean, the Sun was rotating faster, generating a stronger stellar dynamo and therefore the solar wind was more intense than today (Vidotto, 2021). An increased solar wind strength causes greater interaction with the upper atmosphere and greater escape of ions assuming a constant level of protection from Earth‘s magnetosphere. Previous magnetohydrodynamic simulations have suggested that if Earth‘s magnetic field was half its present day strength 3.5 Ga ago, the area of the polar cap (the area containing open dipolar magnetic field lines, allowing atmospheric escape via the polar wind) could increase by up to 50% (Sterenborg et al., 2011).

25.04.2024 - 23:52 [ IFLscience.com ]

The Earth’s Magnetic Field Is At Least 3.7-Billion-Years Old, New Evidence Shows

The age of the Earth’s magnetic field remains under question in part because we don’t fully understand what causes it today. We know it is a product of movements in the molten outer core, whose high iron content turns convection currents into a dynamo, and these currents in turn are produced by the solidification of the inner core.

25.04.2024 - 23:45 [ livescience.com ]

Earth‘s magnetic field formed before the planet‘s core, study suggests

(24 April 2024)

Today, the magnetic field is driven by the churning of the liquid part of the core and the transfer of heat from the solid inner core to the convective outer core as the former cools. But researchers think the core didn‘t solidify until about a billion years ago.

25.04.2024 - 23:40 [ United States Geological Survey ]

How does the Earth‘s core generate a magnetic field?

The Earth‘s outer core is in a state of turbulent convection as the result of radioactive heating and chemical differentiation. This sets up a process that is a bit like a naturally occurring electrical generator, where the convective kinetic energy is converted to electrical and magnetic energy. Basically, the motion of the electrically conducting iron in the presence of the Earth‘s magnetic field induces electric currents. Those electric currents generate their own magnetic field, and as the result of this internal feedback, the process is self-sustaining so long as there is an energy source sufficient to maintain convection.

11.04.2024 - 23:15 [ United Nations Office for Outer Space Affairs ]

RESOLUTION ADOPTED BY THE GENERAL ASSEMBLY 2222 (XXI). Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies

(19. Dezember 1966)

Article III

States Parties to the Treaty shall carry on activities in the exploration and use of outer space, including the moon and other celestial bodies, in accordance with international law, including the Charter of the United Nations, in the interest of maintaining international peace and security and promoting international co-operation and understanding.

Article IV

States Parties to the Treaty undertake not to place in orbit around the earth any objects carrying nuclear weapons or any other kinds of weapons of mass destruction, install such weapons on celestial bodies, or station such weapons in outer space in any other manner.

The moon and other celestial bodies shall be used by all States Parties to the Treaty exclusively for peaceful purposes. The establishment of military bases, installations and fortifications, the testing of any type of weapons and the conduct of military manoeuvres on celestial bodies shall be forbidden. The use of military personnel for scientific research or for any other peaceful purposes shall not be prohibited. The use of any equipment or facility necessary for peaceful exploration of the moon and other celestial bodies shall also not be prohibited.

30.01.2024 - 11:25 [ Futurism.com ]

Neuralink Is Now Recruiting Human Subjects

(20.09.2023)

It‘s only a tiny incremental step towards Musk‘s sweeping vision for his company‘s brain chip. In 2020, Musk promised Neuralink devices could solve numerous neurological conditions, including addiction or memory loss, or restore movement for people with spinal cord injuries. He‘s even promised that one day, a Neuralink brain chip could allow for human-to-human telepathy.

In short, despite Musk‘s grand ambitions, Neuralink still has a lot of work to do to catch up with its competitors — and isn‘t about to completely revolutionize the field just yet.

21.10.2023 - 23:00 [ LightReading.com ]

LunaNet: 5G players debate an Internet for the moon

(May 8, 2023)

LunaNet is being developed through NASA‘s Space Communications and Navigation (SCaN) program office, who oversee the operations, maintenance and advancement of NASA‘s current networked operations.“

21.10.2023 - 21:45 [ CNN ]

Psyche mission launches as NASA’s first trip to a metal world

(October 13, 2023)

To accomplish the rest of the mission, the van-size spacecraft will rely on its new solar electric propulsion system, powered by Hall-effect thrusters, Oh said. The thrusters will utilize the spacecraft’s large solar arrays and “use electricity to ionize xenon gas and accelerate those charged ions through an electric field to very, very high speeds,” Oh said. (…)

Also along for the ride is the Deep Space Optical Communications technology demonstration, or DSOC. Occurring during the first two years of the journey to Psyche, it will be NASA’s most distant experiment of high-bandwidth laser communications, testing the sending and receiving of data to and from Earth using an invisible near-infrared laser.

21.10.2023 - 21:13 [ Massachusetts Institute of Technology ]

ILLUMA-T

NASA wants to update its existing radio communications system on the International Space Station (ISS) with optical communication technology. Optical communication systems, which use laser beams to transmit information through space, promise the ability to transmit data between a spacecraft and Earth at a much higher rate than radio-frequency systems. Our researchers are designing ILLUMA-T*, a laser terminal that will provide an optical communications link from the ISS to NASA‘s Laser Communications Relay Demonstration satellite, which, in turn, will use optical communications to relay the data from the ISS link to a ground terminal at a rate 10 to 100 times faster than current radio frequency communications systems.

21.10.2023 - 20:51 [ National Aeronautics and Space Administration ]

NASA’s Laser Communications Relay: A Year of Experimentation

(Jun 28, 2023)

The Laser Communications Relay Demonstration (LCRD) uses infrared light, or invisible lasers, to transmit and receive signals rather than radio wave systems conventionally used on spacecraft. Infrared light’s tight wavelengths allow space missions to pack significantly more data – 10 to 100 times more – into a single transmission. More data means more discoveries.

Now, at the halfway point in its experimentation phase, LCRD has shown laser communications’ significant advantages over traditional radio wave systems.

21.10.2023 - 16:14 [ ORF.at ]

Forschung als Friedensprojekt

SESAME ist ein Zentrum der Materialforschung. Die im Elektronensynchrotron beschleunigten Teilchen erzeugen elektromagnetische Strahlung in allen Frequenzbereichen – und diese wird verwendet, um Materialien aller Art zu durchleuchten. Das können archäologische Artefakte oder Gewebsproben von Lebewesen sein .

20.09.2023 - 04:33 [ ORF.at ]

KI bestimmt Risiko für genetische Erkrankungen

(19.09.2023)

Die Suche nach den Ursachen für genetische Erkrankungen ist ein großes Unterfangen, bei dem vermehrt auch künstliche Intelligenz (KI) zum Einsatz kommt. Ein neues KI-Werkzeug von Google DeepMind kann das Krankheitsrisiko abschätzen, das von bestimmten Genmutationen ausgeht. Die entstandene Datenbank soll künftige Untersuchungen zur Entstehung der Krankheiten deutlich erleichtern.

20.09.2023 - 04:25 [ European Bioinformatics Institute / European Molecular Biology Laboratory ]

New predictions of genetic variant pathogenicity using AlphaFold protein structures

(19.09.2023)

Google DeepMind has developed a new tool called AlphaMissense, which uses the AlphaFold human protein structure models to predict whether a sequence variant which changes one amino acid in a protein is likely to be tolerated or to impact protein function.

The Ensembl Variant Effect Predictor now integrates Google DeepMind’s new AlphaMissense Catalogue.

20.09.2023 - 04:19 [ endpts.com ]

Al­phaFold, meet Al­phaMis­sense: Google Deep­Mind‘s AI suc­ces­sor pre­dicts how 71M mu­ta­tions cause dis­ease

Google Deep­Mind has de­vel­oped an AI sys­tem that pre­dicts the chances that tens of mil­lions of ge­net­ic vari­ants will cause dis­ease.

20.09.2023 - 03:49 [ European Bioinformatics Institute / European Molecular Biology Laboratory ]

A more diverse human reference genome

(10 May 2023)

The work was led by the international Human Pangenome Reference Consortium (HPRC), a group funded by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health (NIH) and consisting of 14 institutes, including EMBL’s European Bioinformatics Institute (EMBL-EBI). (…)

The majority of the genomes used to create the human pangenome reference were collected as part of the 1000 genomes project, the largest public catalogue of human variation and genotype data from a wide range of populations. (…)

In order to understand the differences in the genes present across the individual genomes represented in the human pangenome, researchers in EMBL-EBI’s Ensembl team needed to map the high-quality annotations on the reference human genome generated as part of the GENCODE project, across the pangenome.

20.09.2023 - 03:12 [ Wikipedia ]

1000 Genomes Project

Some genomic differences may not affect fitness. Neutral variation, previously thought to be “junk” DNA, is unaffected by natural selection resulting in higher genetic variation at such sites when compared to sites where variation does influence fitness.[14]

It is not fully clear how natural selection has shaped population differences; however, genetic candidate regions under selection have been identified recently. (…)

It was found that on average, each person carries around 250–300 loss-of-function variants in annotated genes and 50-100 variants previously implicated in inherited disorders. Based on the two trios, it is estimated that the rate of de novo germline mutation is approximately 10−8 per base per generation.

20.09.2023 - 02:51 [ National Library of Medicine / National Institutes of Health (NIH) ]

The 1000 Genomes Project: Welcome to a New World

(Dec 2015)

“Now this is not the end… But it is, perhaps, the end of the beginning” as Winston Churchill said. Large-scale sequencing projects will continue for more regional or ethnic groups, in order to extend the global coverage. Much effort will focus on a better understanding of the relationship between genetic variation and common disorders. The translation of this massive genetic information to human health will benefit from the development of complex databases gathering genetic, clinical, and biological data, such as multi-omics profiles, while maintaining protection of potentially sensitive personal information (3). Efforts are also underway to increase genetic awareness in the public and to educate health professionals

20.09.2023 - 02:12 [ GENCODE project ]

GENCODE

The goal of the GENCODE project is to identify and classify all gene features in the human and mouse genomes with high accuracy based on biological evidence, and to release these annotations for the benefit of biomedical research and genome interpretation.

20.09.2023 - 01:59 [ European Molecular Biology Laboratory ]

The Human Genome Project at 20: interview with Ewan Birney

(25 April 2023)

EMBL-EBI Director Ewan Birney was a graduate student in the 90s, when the Human Genome Project was in full swing. On the project’s 20th anniversary, he shares his memories of the slow but incredibly accurate analysis software he developed, how the private initiative sped up the public one, and how a betting book highlighted how little we knew about the human genome at the time.

20.09.2023 - 01:45 [ European Molecular Biology Laboratory ]

DeepMind and EMBL release the most complete database of predicted 3D structures of human proteins

(22 July 2021)

For those scientists who rely on experimental protein structure determination, AlphaFold’s predictions have helped accelerate their research. For example, a team at the University of Colorado Boulder is finding promise in using AlphaFold predictions to study antibiotic resistance, while a group at the University of California San Francisco has used them to increase their understanding of SARS-CoV-2 biology.

The AlphaFold Protein Structure Database builds on many contributions from the international scientific community, as well as AlphaFold’s sophisticated algorithmic innovations and EMBL-EBI’s decades of experience in sharing the world’s biological data. DeepMind and EMBL’s European Bioinformatics Institute (EMBL-EBI) are providing access to AlphaFold’s predictions so that others can use the system as a tool to enable and accelerate research and open up completely new avenues of scientific discovery.

15.09.2023 - 06:42 [ CBS News ]

Hurricane Lee on path for New England and Canada with Category 1 storm expected to be „large and dangerous“

The Category 1 storm, which grew at one point last week to Category 5 strength, was expected to „remain a very large and dangerous cyclone“ as it continued on a trajectory north, according to the National Hurricane Center.

27.08.2023 - 03:15 [ CNN ]

SpaceX, NASA launch four astronauts from four countries

The crew is riding aboard the SpaceX Crew Dragon Endurance capsule on the mission, dubbed Crew-7. The spacecraft launched atop a SpaceX Falcon 9 rocket from NASA’s Kennedy Space Center in Florida at 3:27 a.m. ET Saturday.

The four astronauts on the mission include NASA’s Jasmin Moghbeli, who is serving as mission commander; Danish astronaut Andreas Mogensen representing the European Space Agency; Satoshi Furukawa of the Japan Aerospace Exploration Agency, or JAXA; and Russian cosmonaut Konstantin Borisov of Roscosmos.

01.07.2023 - 17:20 [ Nature.com ]

Giant gravitational waves: why scientists are so excited

On 29 June, four separate teams of scientists made an announcement1–4 that promises to shake up astrophysics: they had seen strong hints of very long gravitational waves warping the Galaxy.

Gravitational waves are ripples in the fabric of space-time that are generated when large masses accelerate. They were first detected in 2015, but the latest evidence hints at ‘monster’ ripples with wavelengths of 0.3 parsecs (1 light year) or more; the waves detected until now have wavelengths of tens to hundreds of kilometres.

Here Nature reports what these monster gravitational waves could mean for our understanding of the cosmos, and how the field could evolve.

01.07.2023 - 17:05 [ New York Times ]

The Cosmos Is Thrumming With Gravitational Waves, Astronomers Find

(June 28, 2023)

The scientists strongly suspect that these gravitational waves are the collective echo of pairs of supermassive black holes — thousands of them, some as massive as a billion suns, sitting at the hearts of ancient galaxies up to 10 billion light-years away — as they slowly merge and generate ripples in space-time.

“I like to think of it as a choir, or an orchestra,” said Xavier Siemens, a physicist at Oregon State University who is part of the North American Nanohertz Observatory for Gravitational Waves, or NANOGrav, collaboration, which led the effort. Each pair of supermassive black holes is generating a different note, Dr. Siemens said, “and what we’re receiving is the sum of all those signals at once.”

01.07.2023 - 16:50 [ Institute of Physics - IOP.org ]

Searching for the Nano-Hertz Stochastic Gravitational Wave Background with the Chinese Pulsar Timing Array Data Release I

(Published 29 June 2023)

Observing and timing a group of millisecond pulsars with high rotational stability enables the direct detection of gravitational waves (GWs). The GW signals can be identified from the spatial correlations encoded in the times-of-arrival of widely spaced pulsar-pairs. The Chinese Pulsar Timing Array (CPTA) is a collaboration aiming at the direct GW detection with observations carried out using Chinese radio telescopes. This short article serves as a „table of contents“ for a forthcoming series of papers related to the CPTA Data Release 1 (CPTA DR1) which uses observations from the Five-hundred-meter Aperture Spherical radio Telescope. (…)

A Pulsar Timing Array (PTA; Foster & Backer 1990) is an array of pulsars, which are regularly observed. The times-of-arrival (TOAs) are measured for pulses that we see beams of electromagnetic waves emitted by the pulsars sweeping over the Earth. As the directions of the radiation beam and the pulsar rotational axis do not coincide, we observe this radiation as regular pulses synchronized to the pulsar rotation (Gold 1969).

01.07.2023 - 16:38 [ Richard Panek / Washington Post ]

Everything you thought you knew about gravity is wrong

(02.08.2019)

We don’t know what gravity is.

Say that to the average person, and the answer you’ll probably get is some version of: “What are you talking about? Gravity is the force of attraction that makes things fall straight down.” But say it to a physicist, and the answer you’ll get is, “That’s right.”

I know, because those are the two answers I’ve been getting for the past few years, ever since I figured out that nobody knows what gravity is, and that just about nobody knows that nobody knows what gravity is. The exception is physicists: They know that nobody knows what gravity is, because they know that they don’t know what gravity is.

01.07.2023 - 16:32 [ Physics & Astronomy International Journal / medcraveonline.com ]

About the nature of gravitational and gravity waves

(March 20, 2018)

Gravitational waves, which Albert Einstein predicted in 1916.2 were a riddle until 14 September 2015. Gravitational waves are small deformations of the four dimensional space–time geometry. They propagate with the speed of light and they are generated by catastrophic events in the Universe, in which strong gravitational fields and sudden acceleration (or deceleration) of asymmetric distribution of large masses are involved. In the other words, according to the theory of relativity, any accelerating or decelerating massive object that isn’t spherically or cylindrically symmetrical generates detectable gravitational waves. That object could be for example neutron star or black hole binary system. Gravitational waves are also produced by cosmological explosions such as supernova. Gravity is the weakest of the four fundamental forces, it is known for a very long time, but still there is no a good unique gravity force (field) theory.

14.06.2023 - 13:12 [ National Aeronautics and Space Administration ]

Pioneer 10

Firsts:

– First spacecraft placed on a trajectory to escape the solar system into interstellar space
– First spacecraft to fly beyond Mars
– First spacecraft to fly through the main asteroid belt
– First spacecraft to fly past Jupiter
– Crossed the orbit of Neptune to become the first human-made object to go beyond Neptune
– First spacecraft to use all-nuclear electrical power

Key Dates:

March 2, 1972: Launch

July 15, 1972: Spacecraft entered the asteroid belt

Dec. 4, 1973: Pioneer 10’s closest approach to Jupiter

Feb. 1976: Pioneer crossed Saturn’s orbit

June 13, 1983: Pioneer 10 crossed the orbit of Neptune

March 31, 1997: Routine contact with spacecraft terminated

Jan. 23, 2003: Pioneer 10‘s last signal is received on Earth

14.06.2023 - 13:08 [ NASA New Horizons / Twitter ]

#OTD in 2019, @NASA‘s #NewHorizons flew by Arrokoth, the farthest object ever explored by spacecraft. Arrokoth is about about 50 AU, or 4 billion miles from the Sun. New Horizons is ~56 AU from Earth and will join Voyagers 1 & 2 in interstellar space in the 2040s.

14.06.2023 - 12:59 [ Youtube ]

5 Spacecraft Are Leaving The Solar System. What Did They See In Their Journey?

Pioneer 10: Pioneer 10 was launched in 1972 to explore the planets of the solar system. It achieved the first flyby of Mars, the first trip through the asteroid belt, and Jupiter‘s first flyby. It was the first time NASA had used nuclear energy to power its spacecraft. So, after Pioneer 10 passed Jupiter in 1973, it still had ample energy to keep going. Initially planned for 21 months, it continued to communicate with Earth for a total of 30 years.

14.06.2023 - 12:50 [ Space.com ]

What Spacecraft Will Enter Interstellar Space Next?

(January 30, 2019)

This milestone — reaching interstellar space — can be considered leaving the solar system by a certain definition. Let‘s be clear about what that entails. In 1990, the New York Times reported that Pioneer was reported to leave the solar system when it flew past Neptune‘s orbit. That‘s not what Voyager 2‘s scientists used to make their determination, however. Instead, the more recent measurements consider the crossing of the sun‘s heliopause, the theoretical boundary to its heliosphere, to be the determining factor for entering interstellar space. The heliosphere is a bubble of charged particles created by and flowing past the sun. Scientists use it to mark where interstellar space begins.

14.06.2023 - 12:47 [ ORF.at ]

Raumsonde „Pioneer 10“ 40 Jahre aus Sonnensystem heraus

Am 13. Juni 1983 durchflog „Pioneer 10“ die Umlaufbahn des Neptun und wurde so laut NASA zum ersten menschengemachten Raumschiff, das am weitestentfernten bekannten Planeten unseres Sonnensystems vorbeiflog. Neptun ist im Mittel etwa 4,5 Milliarden Kilometer von der Sonne entfernt.

Mit „Pioneer 11“ und den beiden „Voyager“-Sonden folgten später ähnliche Missionen. „Voyager 1“ überholte „Pioneer 10“ schließlich als am weitesten von der Erde entferntes menschengemachtes Objekt. Zum bisher letzten Mal schickte „Pioneer 10“ im Jänner 2003 Daten, ein Kontaktversuch im März 2006 scheiterte.

24.04.2023 - 15:18 [ New York Times ]

Northern Lights Are Seen in Places Where They Normally Aren’t

“The sun spit off a big blob of plasma,” Mr. Steenburgh said. The burst of energy, which has its own magnetic field, had been moving through space and reached Earth’s magnetic field on Sunday, when the two collided to create a geomagnetic storm, he said. “It got our magnetosphere pretty revved up.”

When this happens, the aurora can be seen closer to the Equator, Mr. Steenburgh said. Such events are not that uncommon, with about 100 occurring every 11 years, he said, adding that the storm can also disturb high frequency radio used at sea and by airlines.

24.04.2023 - 15:14 [ AccuWeather.com ]

RECORD BREAKING: More than 400 tornadoes in the first three months of 2023

According to the National Weather Service, 466 tornadoes have struck since the beginning of the year. That’s the highest number since they started keeping track in 1950.

24.04.2023 - 13:21 [ Science.org ]

A global environmental crisis 42,000 years ago

(19 Feb 2021)

Do terrestrial geomagnetic field reversals have an effect on Earth‘s climate? Cooper et al. created a precisely dated radiocarbon record around the time of the Laschamps geomagnetic reversal about 41,000 years ago from the rings of New Zealand swamp kauri trees. This record reveals a substantial increase in the carbon-14 content of the atmosphere culminating during the period of weakening magnetic field strength preceding the polarity switch. The authors modeled the consequences of this event and concluded that the geomagnetic field minimum caused substantial changes in atmospheric ozone concentration that drove synchronous global climate and environmental shifts.

(…)

We precisely characterize the geomagnetic reversal and perform global chemistry-climate modeling and detailed radiocarbon dating of paleoenvironmental records to investigate impacts. We find that geomagnetic field minima ~42 ka, in combination with Grand Solar Minima, caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record.

24.04.2023 - 13:16 [ ORF.at ]

Erdmagnetfeld: Polwanderung veränderte das Weltklima

Ungefilterte Strahlung aus dem Weltraum zerriss Luftpartikel in der Erdatmosphäre, trennte Elektronen ab und emittierte Licht. Diese ionisierte Luft brutzelte die Ozonschicht weg, heißt es in einer Presseaussendung zur Studie. In Folge dürften überall auf dem Globus Polarlichter aufgetaucht sein, nicht nur rund um den geographischen Nord- und Südpol wie heute. (…)

Das Erdmagnetfeld schwächelt bereits seit rund 2.000 Jahren wieder. Verglichen mit den ersten direkten Messungen vor 170 Jahren wurde eine Abschwächung um neun Prozent festgestellt, im Bereich des Südatlantiks sogar um dreißig Prozent.

24.04.2023 - 13:11 [ rp-online.de ]

Magnetfeld der Erde beeinflusst das Klima

(12.01.2009)

Allerdings könne die Studie nicht in einen direkten Zusammenhang mit der Erderwärmung gestellt werden, betonte der Wissenschaftler. Hier sei es vor allem das Kohlendioxid (CO2), das die entscheidende Rolle spiele.

24.04.2023 - 12:25 [ Geophysical Research Letters 35(16) / researchgate.net ]

Magnetic effect on CO 2 solubility in seawater: A possible link between geomagnetic field variations and climate

(August 2008)

Correlations between geomagnetic-field and climate parameters have been suggested repeatedly, but possible links are controversially discussed. Here we test if weak (Earth-strength) magnetic fields can affect climatically relevant properties of seawater. We found the solubility of air in seawater to be by 15% lower under reduced magneticfield (20 mT) compared to normal field conditions (50 mT). The magnetic-field effect on CO2 solubility is twice as large, from which we surmise that geomagnetic field variations modulate the carbon exchange between atmosphere and ocean. A 1% reduction in magnetic dipole moment may release up to ten times more CO2 from the surface ocean than is emitted by subaerial volcanism.