Archiv: solar activity / solar wind


04.11.2019 - 19:38 [ ScienceNews.org ]

Voyager 2 reveals the dynamic, complex nature of the solar system’s edge

Despite encountering the heliopause at different times and locations — the two spacecraft are farther from each other than each are from the sun — some things looked similar. The magnetic field looked pretty much the same on the inside and the outside of the boundary: Somehow, the sun’s magnetic field lines up nearly perfectly with the local galactic field, contrary to expectations. “We could dismiss that as coincidence in one case, but we can’t do that twice,” study coauthor Leonard Burlaga, of NASA’s Goddard Space Flight Center in Greenbelt, Md., said in the news conference.

04.11.2019 - 19:30 [ Nature ]

Energetic charged particle measurements from Voyager 2 at the heliopause and beyond

Here, we report measurements of energetic (>28 keV) charged particles on V2 from the interface region between the heliosheath, dominated by heated solar wind plasma, and the VLISM, expected to contain cold non-solar plasma and the Galactic magnetic field. The number of particles of solar origin began a gradual decrease on 7 August 2018 (118.2 au), while those of Galactic origin (Galactic cosmic rays) increased ~20% in number over a period of a few weeks. An abrupt change occurred on 5 November when V2 was located at 119 au, with a decrease in the number of particles at energies of >28 keV and a corresponding increase in the number of Galactic cosmic rays of energy E > 213 MeV. T

04.11.2019 - 19:19 [ theGuardian.com ]

Nasa’s Voyager 2 sends back its first signal from interstellar space

The shape depends, in a complex way, on the relative strengths of the magnetic fields inside and outside of the heliosphere, and the latest measurements are suggestive of a more spherical form.

01.11.2019 - 06:33 [ Telegraph.co.uk ]

Sun’s protective ‚bubble‘ is shrinking

(18.10.2008)

The protective bubble around the sun that helps to shield the Earth from harmful interstellar radiation is shrinking and getting weaker, Nasa scientists have warned.

01.11.2019 - 06:29 [ National Aeronautics and Space Administration ]

Solar Activity Forecast for Next Decade Favorable for Exploration

(12.06.2019)

The Sun’s activity rises and falls in an 11-year cycle. The forecast for the next solar cycle says it will be the weakest of the last 200 years. The maximum of this next cycle – measured in terms of sunspot number, a standard measure of solar activity level – could be 30 to 50% lower than the most recent one. The results show that the next cycle will start in 2020 and reach its maximum in 2025.

01.11.2019 - 06:23 [ National Aeronautics and Space Administration ]

Pressure Runs High at Edge of Solar System

(08.10.2019)

The scientists noted that the change in galactic cosmic rays wasn’t exactly identical at both spacecraft. At Voyager 2 inside the heliosheath, the number of cosmic rays decreased in all directions around the spacecraft. But at Voyager 1, outside the solar system, only the galactic cosmic rays that were traveling perpendicular to the magnetic field in the region decreased.

01.11.2019 - 06:17 [ Sciencealert.com ]

Voyager Mission Reveals Unexpected Pressure at The Edge of The Solar System

(10.10.2019)

There was one other surprise to come. The wave’s passage lined up with an apparent drop in the intensity of high speed particles called cosmic rays. The fact each of the probes experienced this same thing in two different ways gives astrophysicists yet another mystery to solve.

„Trying to understand why the change in the cosmic rays is different inside and outside of the heliosheath remains an open question,“ says Rankin.

01.11.2019 - 06:03 [ EOS.org ]

What Inflates the Solar Bubble? Voyagers Count What’s Missing

(17.10.2019)

We’re all living in a bubble.

In fact, the Sun and the entire solar system exist in a bubble that separates us from interstellar space. But what keeps that bubble inflated? A recent paper found that scientists can account for only 82% of the pressure that steadies the solar bubble, or heliosphere, against pressure from galactic headwinds. The source of 18% of the pressure is still unknown.

25.09.2019 - 19:31 [ 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.

25.09.2019 - 19:23 [ Phys.org ]

Strong planetary magnetic fields like Earth’s may protect oceans from stellar storms

(14.03.2019)

„Magnetic fields appear to play an essential role in making planets habitable, so I wanted to find out how Earth’s magnetic field compared to those of other potentially habitable planets,“ she said.

Ms McIntyre said Earth’s strong magnetic field had probably played an important role in protecting the atmosphere from the solar wind and keeping the planet wet and habitable.

„Venus and Mars have negligible magnetic fields and do not support life, while Earth’s magnetic field is relatively strong and does,“ she said.

25.09.2019 - 19:19 [ NASA ‏/ Twitter ]

Unlike Earth, Mars does not have a magnetic field to shield its atmosphere from solar wind:

(05.11.2015)

25.09.2019 - 19:12 [ NationalGeographic.com ]

Rewind the Red Planet: See the Surprising Ways Mars Has Changed in 3 Billion Years

(21.11.2016)

Mars today is a chilly desert. But ancient landscapes reveal a times when water may have flowed freely. Scroll to see how the red planet has evolved

25.09.2019 - 18:56 [ National Aeronautics and Space Administration ]

Why doesn’t Venus have a magnetic field ?

Current theories of the formation and evolution of the terrestrial planets do support an Earth scale magnetic dipole (magnetic field) on Venus for perhaps the first billion years or so after formation.

25.09.2019 - 18:47 [ European Planetary Science Congress / American Astronomical Society's Division for Planetary Sciences ]

A view to the possible habitability of ancient Venus over three billion years

(20.09.2019)

The long-term evolutionary history of Venus’ climate largely remains a mystery.

11.08.2019 - 21:54 [ Observatoire de Paris ]

Centennial cycles of the solar activity and Earth rotation

(Oktober 2011)

The irregular and long-term variations of the Earth rotation are mainly caused by the displacements
of matter in different parts of the planet which excitation mechanism is the influence of the Sun and
solar activity cycles. The solar cycles can drive great number of geodynamical processes connected with the convections of the Earth fluids on the surface and inside the Earth. Many of climate and weather parameters are affected directly by the variations of the solar activity.

11.08.2019 - 21:47 [ Harvard.edu ]

Centennial cycles of the solar activity and Earth rotation

(Oktober 2011)

The centennial variations of the Universal Time UT1 and Length of Day LOD are investigated by means of long historical observational series of UT1 and LOD variations, which cover time span more than 3 centuries long. The correlation between the centennial cycles of the Earth rotation, climate and Total Solar Irradiance TSI is determined using the time series of North America temperature (2.2Ka) and precipitation (8Ka), Mean Sea Level MSL variations at Stockholm tide gauge station since 1774 and reconstructed TSI variations since 843. The model of the solar influences on the centennial and decadal cycles of the Earth rotation is based on a main centennial cycle and harmonics, ending by oscillation with period around 9a.

11.08.2019 - 21:38 [ Nils-Axel Mörner / suanet.ac.tz ]

Solar Wind, Earth’s Rotation and Changes in Terrestrial Climate

(08.03.2013)

Another effect of the interaction between the Solar Wind and the Earth’s magnetic field seems to be that it affects the Earth’s rate of rotation where Solar Minima lead to accelerations and Solar Maxima to decelerations (as discussed in previous papers; [2,5-10]). Several authors have noted a correlation between sunspot activity and Earth’s rotation [2,8-23] or Solar-planetary cycles and Earth’s rotation [10,24-32].

Golovkov [13] plotted Earth’s rate of rotation (spin rate) against sunspot numbers and found that high spin rates correlated with low sunspot numbers and low spin rates with high sunspot numbers. Mörner [2] plotted LOD against sunspot numbers for the period 1831–1995 and found a linear relationship where low LOD values (high spin rate) correlated with low sunspot numbers and high LOD values with high sunspot numbers. Consequently, the Earth’s rotation accelerates at low solar activity and decelerates at high solar activity.

The relations among solar activity, Solar Wind, variations in Earth’s atmospheric shielding capacity and variations in the Earth’s rate of rotation are expressed in Fig. 1

11.08.2019 - 21:32 [ Nils-Axel Mörner / core.ac.uk ]

Solar Wind, Earth’s Rotation and Changes in Terrestrial Climate

(2013)

Solar variability affects Earth climate. It is proposed that this forcing primarily goes via the interaction of the Solar Wind with the Earth’s magnetosphere, rather than via changes in irradiance, which is generally assumed. The cyclic variations in Solar Wind emission generate corresponding changes in the Earth’s rate of rotation (LOD), as recorded by correlations between sunspot numbers and LOD-variations. Variations in Earth’s rotation affect not only the atmospheric circulation but also the ocean circulation.

11.08.2019 - 15:25 [ Harvard.edu ]

Equatorial solar rotation and its relation to climatic changes

(29. September 1977)

During the years from 1965 to 1976, the magnitude of the solar rotation speed averaged annually showed a good inverse correlation with the annual relative sunspot numbers. It is suggested that this variation of the equatorial solar rotation speed may be responsible for the earth’s present unusual climatic conditions. A similarity concerning the low sunspot activity for 1976 and the year 1643, just before the beginning of the Maunder Minimum (1645-1715) with its very severe climatic conditions, is pointed out. It appears, therefore, likely that the present unusual climatic conditions will remain as long as the solar activity continues to decrease.

11.08.2019 - 14:14 [ National Aeronautics and Space Administration ]

The Space Station Crosses a Spotless Sun

(15.07.2019)

Transiting the Sun is not very unusual for the ISS, which orbits the Earth about every 90 minutes, but getting one’s timing and equipment just right for a great image is rare. Strangely, besides that fake spot, in this recent two-image composite, the Sun lacked any real sunspots. The featured picture combines two images — one capturing the space station transiting the Sun — and another taken consecutively capturing details of the Sun’s surface. Sunspots have been rare on the Sun since the dawn of the current Solar Minimum, a period of low solar activity. For reasons not yet fully understood, the number of sunspots occurring during both the previous and current solar minima have been unusually low.

11.08.2019 - 14:03 [ Global Warming Policy Forum (GWPF) ]

Solar Cycle 25: May Be The Smallest In Over 300 Years

(26.01.2012)

Livingston and Penn provided the first hard estimate of Solar Cycle 25 amplitude based on a physical model. That estimate is 7, which would make it the smallest solar cycle for over 300 years.

This is figure 2 from their paper:

Livingston and Penn have been tracking the decline in sunspot magnetic field, predicting that sunspots will disappear when the umbral magnetic field strength falls below 1,500 gauss, as per this figure from their 2010 paper:

11.08.2019 - 13:58 [ NationalGeographic.com ]

Sun Headed Into Hibernation, Solar Studies Predict: Sunspots may disappear altogether in next cycle.

(14.06.2011)

This time, however, the rush to the poles is more of a crawl, which means we could be headed toward a very weak solar maximum in 2013—and it may delay or even prevent the start of the next solar cycle.

Taken together, the three lines of evidence strongly hint that Solar Cycle 25 may be a bust, the scientists said today during a meeting of the American Astronomical Society in Las Cruces, New Mexico.

11.08.2019 - 13:45 [ National Aeronautics and Space Administration ]

Long Range Solar Forecast: Solar Cycle 25 peaking around 2022 could be one of the weakest in centuries.

(10.05.2006)

How do you observe a belt that plunges 200,000 km below the surface of the sun?

„We do it using sunspots,“ Hathaway explains. Sunspots are magnetic knots that bubble up from the base of the conveyor belt, eventually popping through the surface of the sun. Astronomers have long known that sunspots have a tendency to drift—from mid solar latitudes toward the sun’s equator. According to current thinking, this drift is caused by the motion of the conveyor belt. „By measuring the drift of sunspot groups,“ says Hathaway, „we indirectly measure the speed of the belt.“

11.08.2019 - 13:22 [ National Oceanic and Atmospheric Administration (NOAA.gov) ]

Space Weather Impacts On Climate

All weather on Earth, from the surface of the planet out into space, begins with the Sun. Space weather and terrestrial weather (the weather we feel at the surface) are influenced by the small changes the Sun undergoes during its solar cycle.

(…)

The duration of solar minimum may also have an impact on Earth’s climate. During solar minimum there is a maximum in the amount of Cosmic rays, high energy particles whose source is outside our Solar system, reaching earth. There is a theory that cosmic rays can create nucleation sites in the atmosphere which seed cloud formation and create cloudier conditions. If this were true, then there would be a significant impact on climate, which would be modulated by the 11-year solar cycle.

02.08.2019 - 02:09 [ CNN ]

Bill Nye’s experimental spacecraft that sails on sunlight declares mission success

The Planetary Society spent a decade working up to the LightSail 2 mission and scraping together the $7 million needed to get the project off the ground. All told, 50,000 supporters from 109 countries donated to the initiative, according to Planetary Society COO Jennifer Vaughn.

13.07.2019 - 16:40 [ EOS.org ]

The Thermosphere Responds to a Weaker Than Normal Solar Cycle

The cooling near solar minimum is natural and specific to the thermosphere. The cooling thermosphere does not affect the troposphere, the layer of the atmosphere closest to Earth’s surface where people live. The temperatures we experience on the ground do not get colder because of this solar cycle. NASA and other climate researchers continue to see a warming trend in the troposphere. These two effects are ongoing but unrelated.

Nitric oxide and carbon dioxide play important roles in cooling the thermosphere.

16.06.2019 - 11:31 [ Christina H Koch, current resident of the International @Space_Station / Twitter ]

Years ago at the South Pole, I looked up to the aurora for inspiration through the 6-month winter night. Now I know they’re just as awe inspiring from above. #nofilter

(10.06.2019)

05.06.2019 - 20:00 [ Phys.org ]

Earth’s magnetic poles could start to flip. What happens then?

(07.12.2018)

‚The geomagnetic field has been decaying for the last 3,000 years,‘ said Dr. Nicolas Thouveny from the European Centre for Research and Teaching of Environmental Geosciences (CEREGE) in Aix-en-Provence, France. ‚If it continues to fall down at this rate, in less than one millennium we will be in a critical (period).‘

05.06.2019 - 19:41 [ Metro.co.uk ]

The sun has ‘reached solar minimum’ and its surface is ominously calm

But Nasa images have revealed that the face of our star is looking ominously calm right now, prompting claims it’s reached a stage of its cycle called the solar minimum.

During the minimum, there are significantly fewer sunspots and its magnetic field weakens, allowing cosmic rays from outside our solar system to rain down on Earth.

30.05.2019 - 16:24 [ scitecheuropa.eu ]

Solving a century-long mystery: the origin of galactic cosmic rays

(04.04.2019)

The word ‘astronomy’ means the direct observations of extra-terrestrial objects. This definition is relevant to photons, neutrinos, and gravitational waves, i.e. massless, neutral and stable particles. But for cosmic ray electrons, protons, and nuclei, the term ‘astronomy’ is used with a certain reservation. Because of the deflections of electrically charged particles in the chaotic interstellar and intergalactic magnetic fields, the information about their original directions pointing to the sites of their production is lost. Instead, on the Earth, we detect an (almost) isotropic flux of cosmic rays contributed by a huge number of galactic and extragalactic sources.

30.05.2019 - 16:11 [ arxiv.org ]

Hypothesis: Muon Radiation Dose and Marine Megafaunal Extinction at the end-Pliocene Supernova

(November 2018)

Considerable data and analysis support the detection of one or more supernovae (SNe) at a distance of about 50 pc, ∼2.6 million years ago. This is possibly related to the extinction event around that time and is a member of a series of explosions that formed the Local Bubble in the interstellar medium. We build on previous work, and propagate the muon flux from SN-initiated cosmic rays from the surface to the depths of the ocean. We find that the radiation dose from the muons will exceed the total present surface dose from all sources at depths up to 1 km and will persist for at least the lifetime of marine megafauna. It is reasonable to hypothesize that this increase in radiation load may have contributed to a newly documented marine megafaunal extinction at that time.

30.05.2019 - 15:55 [ New York Times ]

STUDY HINTS EXTINCTIONS STRIKE IN SET INTERVALS

(11. Dezember 1983)

At a conference on mass extinctions, held in August at Northern Arizona University in Flagstaff, Dr. Sepkoski said the timing of these events suggested that “there is indeed a statistically significant periodicity in the observed distribution of events of mass or accelerated extinction over the last 250 million years.“ Search for Answers

He confessed this “stumped“ him and Dr. Raup, saying: “We are aware of no documented process with a cycling time approximately 26 million years. But with that long a cycle, we suspect that the forcing agent will not be terrestrial but rather solar or galactic.“

30.05.2019 - 15:49 [ Harvard.edu ]

Cosmic-ray volleys from the Galactic Center and their recent impact on the earth environment

Authors: Laviolette, P. A.
Journal: Earth, Moon, and Planets (ISSN 0167-9295), vol. 37, March 1987, p. 241-286.

25.05.2019 - 15:17 [ Phys.org ]

Scientists predict sun’s activity will be weak during next solar cycle

(08.04.2019)

„We expect Solar Cycle 25 will be very similar to Cycle 24: another fairly weak cycle, preceded by a long, deep minimum,“ said panel co-chair Lisa Upton, Ph.D., solar physicist with Space Systems Research Corp. „The expectation that Cycle 25 will be comparable in size to Cycle 24 means that the steady decline in solar cycle amplitude, seen from cycles 21-24, has come to an end and that there is no indication that we are currently approaching a Maunder-type minimum in solar activity.“

25.05.2019 - 15:09 [ NationalGeographic.com ]

Surprise: Solar System „Force Field“ Shrinks Fast

(01.10.2010)

„If we’ve learned anything from IBEX so far, it is that the models that we’re using for interaction of the solar wind with the galaxy were just dead wrong,“ David McComas, principal investigator for the IBEX program, said during a NASA press conference Thursday.

For starters, it’s been assumed that the heliosphere’s expansion and contraction follows the sun’s roughly 11-year activity cycle, during which the flow rate of charged particles, or solar wind, fluctuates.

25.05.2019 - 14:49 [ voyager.jpl.nasa.gov ]

NASA Voyager 2 Could Be Nearing Interstellar Space

(05.10.2018)

NASA’s Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system.

25.05.2019 - 14:49 [ scitechdaily.com ]

NASA Voyager 2 Nearing Interstellar Space, Measures Increase in Cosmic Rays

(06.10.2018)

NASA’s Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system.

25.05.2019 - 14:36 [ NASA Solar System ‏/ Twitter ]

The Space Between: interstellar space is often called the space between the stars, but more specifically, it’s the region between our Sun’s heliosphere and the astrospheres of other stars. Find out how that works

(27.03.2019)

25.05.2019 - 13:27 [ HNGN.com ]

Sun’s Magnetic Field To ‚Flip‘ Causing ‚A Ripple Effect‘ Past Pluto (VIDEO)

(06.08.2013)

The polar switch also affects cosmic rays, which can endanger satellites and astronauts. Disturbances in the rays could even affect Earth’s climate.

The sheet acts as a „shield“ against these rays, and a wavy current sheet can be even more effective.

25.05.2019 - 13:09 [ Gizmodo.com ]

Pluto Is Emitting X-Rays, and That’s Really Weird

(16.09.2016)

The most likely explanation, according to Wolk, is that high energy particles from the solar wind are colliding with escaped bits of Pluto’s atmosphere—which is mostly nitrogen, carbon, and oxygen—stripping away electrons, and producing an x-ray flare. If true, that’s a very important insight, because it means Pluto’s atmosphere is boiling away into space. Slowly.

(…)

Clearly, more research is needed to figure out exactly why Pluto’s atmosphere is leaky, and what’s responsible.

25.05.2019 - 12:48 [ Obspm.fr - Observatoire de Paris ]

Spring on Pluto: an analysis over 30 years

(10.05.2019)

Thus Pluto had its equinox in 1988, before moving to perihelion (at 30 au) in 1989. Since then, the dwarf planet has continually moved away from the Sun to reach 32 ua in 2016, which represents a loss of 25 % of his average insolation.

Naively, a sharp fall in atmospheric pressure could be expected. In fact, the gas-ice balance of nitrogen imposes that for each degree Kelvin lost at the surface, the pressure should decrease by a factor of two.

But the exact opposite occurs.

25.05.2019 - 12:15 [ Cornell University ]

Pluto’s lower atmosphere and pressure evolution from ground-based stellar occultations, 1988-2016

(06.03.2019)

Results: (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived;

25.05.2019 - 12:09 [ SkepticalScience.com ]

Pluto warms while the sun cools

(Last updated on 15 September 2010 by gpwayne)

Claims that solar system bodies are heating up due to increased solar activity are clearly wrong. The sun’s output has declined in recent decades. Only Pluto and Neptune are exhibiting increased brightness.

25.05.2019 - 11:07 [ National Aeronautics and Space Administration ]

A Gloomy Mars Warms Up

(14.05.2007)

They discovered that a wind-whipped, dusty surface has a measurable effect on the amount of sunlight that is reflected by the planet. The results of this research show that an increase in darkened surface areas may account for a one degree Fahrenheit rise in the surface air temperature of the planet.

25.05.2019 - 09:25 [ Nature.com ]

Less absorbed solar energy and more internal heat for Jupiter

(13.09.2018)

The radiant energy budget and internal heat are fundamental properties of giant planets, but precise determination of these properties remains a challenge.

(…)

Furthermore, the significant wavelength dependency of Jupiter’s albedo implies that the radiant energy budgets and internal heat of the other giant planets in our solar system should be re-examined.

(…)

Furthermore, the transfer and distribution of radiant energy within the atmospheric systems modify the thermal structure and hence generate the mechanical energy to drive atmospheric circulation, weather, and climate. The radiant energy budget and the related internal heat of the giant planets also bear upon their evolutionary history.

29.04.2019 - 13:21 [ 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.

29.04.2019 - 13:15 [ Stanford University ]

ON THE WEAKENING OF THE POLAR MAGNETIC FIELDS DURING SOLAR CYCLE 23

(20. Dezember 2009)

The Sun’s polar fields are currently ∼40% weaker than they were during the previous three sunspot minima. This weakening has been accompanied by a corresponding decrease in the interplanetary magnetic field (IMF) strength, by a ∼20% shrinkage in the polar coronal-hole areas, and by a reduction in the solar-wind mass flux over the poles. It has also been reflected in coronal streamer structure and the heliospheric current sheet, which only showed the expected flattening into the equatorial plane after sunspot numbers fell to unusually low values in mid-2008. From latitude–time plots of the photospheric field, it has long been apparent that the polar fields are formed through the transport of trailing-polarity flux from the sunspot latitudes to the poles.

29.04.2019 - 12:48 [ Nature.com ]

Earth’s magnetic field is acting up and geologists don’t know why

(9. Januar 2019)

The magnetic pole is moving so quickly that it has forced the world’s geomagnetism experts into a rare move.

On 15 January, they are set to update the World Magnetic Model, which describes the planet’s magnetic field and underlies all modern navigation, from the systems that steer ships at sea to Google Maps on smartphones.