Archiv: interstellar medium


15.11.2019 - 17:47 [ arxiv.org ]

The large-scale ionization cones in the Galaxy

(05.10.2019)

Our time-dependent Seyfert flare models adequately explain the observations and indicate the Seyfert flare event took place T_o = 3.5 +/- 1 Myr ago.

15.11.2019 - 17:32 [ ScienceAlert.com ]

Something in The Centre of Our Galaxy Colossally Erupted 3.5 Million Years Ago

(06.10.2019)

In 2013, astrophysicist Joss Bland-Hawthorn of the University of Sydney and the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and colleagues estimated that the event occurred between 1 and 3 million years ago.

Now, more observations taken using the Hubble Space Telescope – and therefore a bigger dataset – have provided even more compelling evidence for the event. And the team has been able to narrow down a timeframe for both when the event occurred, as well as its duration.

15.11.2019 - 17:29 [ arxiv.org ]

Fossil imprint of a powerful flare at the Galactic Centre along the Magellanic Stream

(21.09.2013)

Thus it is likely that the Stream emission arose from a `Seyfert flare‘ that was active 1-3 Myr ago, consistent with the cosmic ray lifetime in the Fermi bubbles. Sgr A* activity today is greatly suppressed (70-80 dB) relative to the Seyfert outburst…

15.11.2019 - 17:16 [ Forbes ]

The Milky Way’s Supermassive Black Hole Erupted Two Million Years Ago

(25.09.2013)

The key the astronomers found was actually discovered 20 years old, in the form of a strange glow that astronomers had noticed in the Magellanic Stream. The Magellanic Stream is composed of large clouds of gas – mostly hydrogen – that stretch for light years in the wake of the Milky Way’s two companion Galaxies, the Large and Small Magellanic Clouds. The Stream is about 2 billion years old.

„We didn’t understand the cause. Then suddenly we realised it must be the mark, the fossil record, of a huge outburst of energy from the centre of our Galaxy,“ remarked researcher Joss Bland-Hawthorn in a press release.

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.

04.11.2019 - 18:51 [ ORF ]

„Magnetische Wand“ im interstellaren Raum

Nach Jahrzehnten haben sie nun die Grenze der Heliosphäre passiert und sind damit auf dem Weg zu den Sternen.

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.

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.

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)

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.

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

20.11.2018 - 13:16 [ CBNcom ]

Something’s Happening to the Sun Right Now, Here’s What It Means for Earth

(13.11.2018) If the trend continues, the NASA scientist says we could see record cold in a matter of months.

„The thermosphere always cools off during Solar Minimum. It’s one of the most important ways the solar cycle affects our planet,“ Mlynczak said.

20.11.2018 - 13:15 [ National Aeronautics and Space Administration ]

Solar Wind Loses Power, Hits 50-year Low

Sept. 23, 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.“

20.11.2018 - 13:13 [ 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 - 13:08 [ National Aeronautics and Space Administration ]

Excitement Increases as Voyager 2 sees a decrease in Heliospheric Particles

(14.11.2018) In the following graph of the Low Energy Telescope data, right around the beginning of November, you’ll notice a pretty dramatic change: All of a sudden, the Voyager 2 counting rate of low-energy particles dropped, although it hasn’t yet dropped to nearly zero as it did when Voyager 1 entered interstellar space. Scientists will keep their eye on these graphs …

20.11.2018 - 13:05 [ NASA Sun & Space ‏/ Twitter ]

Excitement goes up ? as @NASAVoyager 2’s count of heliospheric particles goes down These low-energy particles originate within the Sun’s bubble of magnetic influence — the heliosphere — and their count should drop to near-zero in interstellar space:

(17.11.2018)

20.11.2018 - 12:40 [ Scienceblogs.com ]

Why the Earth wears an Antimatter Belt!

(9.8.2011) The Earth’s magnetic field — the same field that causes your compass needle to point North — extends far out into space, and shields us from the high-energy, charged particles that come from not only the Sun, but also from powerful galactic and extra-galactic sources!

The Solar Wind, however, would by far be the most deadly to us, were it not for this magnetic „shield“ that the Earth produces.

20.11.2018 - 12:23 [ qrz.com ]

A new solar index number is being published – Thermosphere Climate Index

(1.10.2018) Hi Everybody;

As the sun plummets into the solar minimum a new index is derived to measure the total energy budget of the planet.

20.11.2018 - 12:20 [ spaceweatherarchive.com ]

The Chill of Solar Minimum

(27.9.2018) As 2018 comes to an end, the Thermosphere Climate Index is on the verge of setting a Space Age record for Cold. “We’re not there quite yet,” says Mlynczak, “but it could happen in a matter of months.”

20.11.2018 - 12:18 [ Phys.org ]

Solar activity is declining—what to expect?

(17.8.2015) The solar cycle is the periodic change in the Sun’s activity and appearance like changes in the number of sunspots. It has an average duration of about 11 years. The current solar cycle began on in January 2008, with minimal activity until early 2010. The sun is now on track to have the lowest recorded sunspot activity since accurate records began in 1750.

01.10.2018 - 20:38 [ 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.

01.10.2018 - 20:31 [ 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.