Archiv: solar systems


15.11.2019 - 15:31 [ Carnegie Science / Youtube ]

Hypervelocity star

(12.11.2019)

The artist impression of the ejection mechanism by the supermassive black hole. Credit: James Josephides (Swinburne Astronomy Productions)

15.11.2019 - 15:21 [ Carnegie Science ]

Runaway star was ejected from the “heart of darkness”

“My favorite part of this discovery is thinking about where this star came from and where it’s going,” said Ji. “It was born in one of the craziest places in the universe, near a supermassive black hole with lots of other nearby star friends; but it’s going to leave our galaxy and die all alone, out in the middle of nowhere. Quite a fall from grace.”

15.11.2019 - 15:06 [ CBS News ]

Supermassive black hole throws star out of Milky Way galaxy at speed of 3.7 million mph

Five million years ago, when humanity’s ancestors were just learning to walk upright, a star was ejected from Sagittarius A*, the supermassive black hole at the center of the Milky Way Galaxy, at a staggering 3.7 million mph. This month, a group of researchers spotted the superfast star traveling relatively close to Earth.

15.11.2019 - 15:00 [ businessinsider.fr ]

A NASA scientist’s incredible animation shows how dinosaurs roamed the Earth on the other side of the Milky Way galaxy

Our sun orbits the galaxy’s center, so many dinosaurs roamed the Earth while the planet was on the other side of the Milky Way.

Our solar system’s orbit keeps us just the right distance from the galaxy’s chaotic center for life to exist.

15.11.2019 - 12:27 [ Dr. Jessie Christiansen ‏/ Twitter ]

I have always been interested in galactic archaeology, but I don’t think this is what they meant. Did you know that dinosaurs lived on the other side of the Galaxy?

15.10.2019 - 18:46 [ CNN ]

Interstellar comet fits right in with our solar system

At the end of August, amateur astronomer Gennady Borisov spotted a new comet while at the MARGO observatory in Crimea. The amateur astronomer used a 0.65-meter telescope he built and saw something that resembled a comet with a short tail.

Observations by NASA’s Jet Propulsion Laboratory Solar System Dynamics Group have supported that …

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.

11.08.2019 - 19:02 [ arxiv.org ]

Anomalous post-newtonian terms and the secular increase of the astronomical unit

(14.10.2018)

In 2004 Krasinsky and Brumberg indicated that the analysis of all available radiometric measurements of distances between the Earth and the planets, and also the observations of martian landers and orbiters, showed that the Astronomical Unit is increasing at a rate 15 ± 4 meters per century [14]. Later on, a more careful analysis by Standish has shown that the secular rate is closer to 7 ± 2 meters per century [26]. Anyway, this is by far too large to be explained by the loss of solar mass due to solar wind and electromagnetic radiation. An explanation based upon tidal friction caused by the bulge produced by Earth gravity on the Sun has been proposed [17]. However, this model has not been validated and the detailed mechanism for this tidal friction is hypothetical. A secular effect on the eccentricity of planetary motions have been also unveiled by the recent detailed analysis of the Lunar orbit. The secular increase of the eccentricity is very small but, however, is clearly within the range of precision of Lunar laser ranging. This kind of unexplained observations,
after discarding any possible conventional explanation, could give rise to an arena where the status of General Relativity as a complete theory of gravity (at least, at the macroscopic level) could be tested.

In this paper we have assumed that a conventional explanation is not possible and that an extra force term is necessary in order to incorporate this behaviour in the post-newtonian formalism.

11.08.2019 - 18:45 [ Newsweek ]

NASA Shows Einstein Was Right: Our Sun Is Losing Mass—and Its Grip on Our Solar System

(19.01.2018)

As our sun gets older, it’s losing mass, and so its gravitational pull becomes weaker. As a result, the orbits of all the planets in our solar system are expanding, not unlike „the waistband of a couch potato in midlife,“ according to a new NASA press statement.

A team of researchers from the Massachusetts Institute of Technology, the University of Maryland and the NASA Goddard Space Flight Center has shown that the aging sun is behaving according to Albert Einstein’s theory of general relativity.

11.08.2019 - 17:11 [ National Aeronautics and Space Administration ]

NASA Team Studies Middle-aged Sun by Tracking Motion of Mercury

(18.01.2018)

Like the waistband of a couch potato in midlife, the orbits of planets in our solar system are expanding. It happens because the Sun’s gravitational grip gradually weakens as our star ages and loses mass.

11.08.2019 - 17:08 [ Sparkonit.com ]

The Orbits Of All The Planets In Our Solar System Are Expanding As The Sun Gets Older, Study On Mercury’s Orbit Reveals

(25.01.2018)

“Mercury is the perfect test object for these experiments because it is so sensitive to the gravitational effect and activity of the Sun,” explained Antonio Genova, the lead author of the study and a MIT researcher working at NASA’s Goddard Space Flight Center.

Researchers were able to make these calculations from the data gathered by NASA’s MESSENGER spacecraft which made three ‘flybys’ of Mercury in 2008 and 2009 and orbited Mercury between March 2011 and April 2015 before it crashed into Mercury in 2015, Mail noted.

11.08.2019 - 16:58 [ ScientificAmerican.com ]

„Astronomical Unit,“ or Earth-Sun Distance, Gets an Overhaul

(14.09.2012)

Without fanfare, astronomers have redefined one of the most important distances in the Solar System. The astronomical unit (au) — the rough distance from the Earth to the Sun — has been transformed from a confusing calculation into a single number. The new standard, adopted in August by unanimous vote at the International Astronomical Union’s meeting in Beijing, China, is now 149,597,870,700 meters — no more, no less.

11.08.2019 - 16:51 [ NewScientist.com ]

Why is the Earth moving away from the sun?

(01.06.2009)

It’s not much – just 15 cm per year – but since that’s 100 times greater than the measurement error, something must really be pushing Earth outward. But what?

One idea is that the Sun is losing enough mass, via fusion and the solar wind, to gradually be losing its gravitational grip (see Astronomical unit may need to be redefined). Other possible explanations include a change in the gravitational constant G, the effects of cosmic expansion, and even the influence of dark matter. None have proved satisfactory.

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.

20.06.2019 - 10:48 [ ABC Australia ]

Our solar system is weird

Saturn is essential for the Grand Tack theory. If there was no Saturn, Jupiter would have stayed close in near the Sun, and some of the super-Earths would have survived, making our solar system just like all those exoplanetary systems out there.

That’s a pretty sweet explanation of how our solar system came to be so unusual. But is the Grand Tack theory right?

Only time – and observational-data-confirming-or-rejecting-testable-predictions – will tell.

05.06.2019 - 20:29 [ University College London ]

Magnetic Rope observed for the first time between Saturn and the Sun

(06.07.2016)

The Cassini spacecraft has been in orbit around Saturn since 2004, and after many years analyzing the data collected, Cassini has observed the first FTE at Saturn.

05.06.2019 - 20:27 [ ScienceMag.org ]

Magnetic Reconnection in the Near Venusian Magnetotail

(04.05.2012)

Observations with the Venus Express magnetometer and low-energy particle detector revealed magnetic field and plasma behavior in the near-Venus wake that is symptomatic of magnetic reconnection, a process that occurs in Earth’s magnetotail but is not expected in the magnetotail of a nonmagnetized planet such as Venus.

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.

29.04.2019 - 10:51 [ Phys.org ]

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

(8. April 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.“

29.04.2019 - 10:50 [ Phys.org ]

Rapid destruction of Earth-like atmospheres by young stars

(24.04.2019)

The high energy radiation is important because it is absorbed high in the atmosphere of a planet, causing the gas to be heated. For the Earth, the gas is heated to temperatures of more than 1000 degrees Celsius in the upper region known as the thermosphere. This is the region in which spacecraft such as satellites and the International Space Station fly. When orbiting young stars with high activity levels, the thermospheres of planets are heated to much higher temperatures which, in extreme cases, can cause the gas to flow away from the planet.

14.04.2019 - 19:50 [ Washington Post ]

Scientists predict a new solar cycle is about to begin and that it might be stronger than the last one

(11. April 2019)

The decline in sunspot activity through cycle 24 was worrisome to some space weather scientists in that it suggested a return to a lengthy “solar drought,” reminiscent of the Maunder Minimum period of 1645-1715. Records show the sun was essentially spotless for this lengthy period, coinciding with the “Little Ice Age” in Europe and tickling the interest of scientists to wonder whether there is a cause-and-effect relationship between solar behavior and Earth’s climate.

14.04.2019 - 19:47 [ Phys.org ]

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

(8. April 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.“

14.04.2019 - 19:46 [ National Aeronautics and Space Administration ]

Solar Wind Loses Power, Hits 50-year Low

(23. September 2008)

In a briefing today at NASA headquarters, solar physicists announced that the solar wind is losing power.

„The average pressure of the solar wind has dropped more than 20% since the mid-1990s,“ says Dave McComas of the Southwest Research Institute in San Antonio, Texas. „This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.“

14.04.2019 - 18:54 [ 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.

11.12.2018 - 02:40 [ BBC ]

Nasa’s Voyager 2 probe ‚leaves the Solar System‘

Decades and billions of kilometres. Voyager 1 departed Earth on 5 September 1977, a few days after its sister spacecraft, Voyager 2.

The pair’s primary objective was to survey the planets Jupiter, Saturn, Uranus and Neptune – a task they completed in 1989.

08.12.2018 - 15:32 [ Huffington Post ]

Waiting For The Next Sunspot Cycle: 2019-2030

(6.12.2017) By Cycle 25 or 26, magnetic fields may be too weak to punch through the solar surface and form recognizable sunspots at all,

08.12.2018 - 15:25 [ Resonance.is ]

Is our solar system heating up?

With the decrease of solar activity, the magnetic field of oursun is losing power too. This heliosphere shields us forming a gigantic bubble which surrounds and protects our solar system from harmful galactic cosmic rays, these high-energy particles that zip through the universe. Thanks to Voyagers 1 leaving the Solar system, we now have a good vision of it and of its shielding effect. It appears to be an indispensable protection for our fast moving throughout the Universe. But, with a weaker heliosphere Earth will begin to endure more and more the cosmic rays.

08.12.2018 - 15:19 [ ScienceMag.com ]

Decades-Long Changes of the Interstellar Wind Through Our Solar System

(6.9.2013) The flow of interstellar gas and dust through the solar system was thought to be unvarying, but Frisch et al. (p. 1080) show that there has been a significant variation of the direction of the flow of interstellar helium through the solar system over the past 40 years.

08.12.2018 - 15:14 [ 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.

20.11.2018 - 15:45 [ NASA Goddard / Youtube ]

NASA | Thermonuclear Art – The Sun In Ultra-HD (4K)

Presented in ultra-high definition, the video presents the dance of the ultra-hot material on our life-giving star in extraordinary detail, offering an intimate view of the grand forces of the solar system.

20.11.2018 - 15:35 [ NASASolarSystem / Youtube ]

Voyager Satellites Find Magnetic Bubbles at Edge of Solar System

(9.11.2011) This ribbon shows the emission of energetic particles and seems to indicate some interaction with interstellar space.

20.11.2018 - 15:33 [ NASA Goddard / Youtube ]

Understanding the Magnetic Sun

(29.1.2016) Grasping what drives that magnetic system is crucial for understanding the nature of space throughout the solar system: The sun’s invisible magnetic field is responsible for everything from the solar explosions that cause space weather on Earth – such as auroras – to the interplanetary magnetic field and radiation through which our spacecraft journeying around the solar system must travel.

20.11.2018 - 15:05 [ 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.

20.11.2018 - 14:47 [ Institute of Electrical and Electronics Engineers ]

The Case of Earth’s Incredible Shrinking Field

(1.11.2006) Earth’s magnetic field has been monitored carefully since the 1830s, when the German polymath Karl Friedrich Gauss invented a way to measure its intensity. Since then, the field has decayed at the ­startling rate of about 5 percent per century