Svensmark, Henrik Evidence
of nearby supernovae affecting life on Earth Mon..
As he puts it: «Today the Royal Astronomical Society in London publishes (online) Henrik Svensmark's latest paper entitled «Evidence
of nearby supernovae affecting life on Earth».
By comparing the brightness of distant, far - away supernovae with the brightness
of nearby supernovae, the scientists discovered that the far - away supernovae were about 25 percent too faint.
A new analysis
of nearby supernovae suggests space might not be expanding as quickly as it once was, a tantalising hint that the source of dark energy may be more exotic than we thought.
2) The nebula began a contraction that may have been triggered by the shock wave
of a nearby supernova.
«CAT scan
of nearby supernova remnant reveals frothy interior.»
Using elaborate computer simulations, a team of researchers from RIKEN in Japan and the Max Planck Institute for Astrophysics (MPA) were able to explain the recently measured spatial distributions of radioactive titanium and nickel in Cassiopeia A, a roughly 340 year old gas remnant
of a nearby supernova.
The cloud may even be much closer than most astronomers think and be part of the debris
of a nearby supernova.
Measurements based on the cosmic microwave background, the earliest light in the universe, suggest one rate of expansion, while measurements
of nearby supernovas suggest a faster one.
Not exact matches
Cause really accretion and a
nearby second generation star going
supernova disturbing a dust cloud thus explaining our high abundance
of higher elements seems like a very excellent explanation.
The
supernova, known as SN1987A, was first seen by observers in the Southern Hemisphere in 1987 when a giant star suddenly exploded at the edge
of a
nearby dwarf galaxy called the Large Magellanic Cloud.
«If the cosmos had been expanding rapidly, the redshifts
of distant
supernovae would be more pronounced when compared to the light emanating from
nearby supernovae.
A new influx
of metalrich dust to the solar system, perhaps from a
nearby supernova, would have augmented isotopes in the outer asteroids but not the inner ones.
Here's a map
of six
supernovas directly seen by human eyes throughout history, and one
nearby explosion that went unnoticed.
Unlike most
supernovae surveys, which look for bright bursts
of light, Kochanek would monitor about 30
nearby galaxies for curious patches
of darkness where a star had suddenly disappeared.
«Massive fails» like this one in a
nearby galaxy could explain why astronomers rarely see
supernovae from the most massive stars, said Christopher Kochanek, professor
of astronomy at The Ohio State University and the Ohio Eminent Scholar in Observational Cosmology.
A good example is the
Nearby Supernova Factory, an experiment that has turned up more than 500 Type Ia
supernovas to help explore the nature
of dark energy.
If shells
of material do exist near bursts, they probably come from the massive stars themselves or from other
supernovas popping off
nearby, he adds.
The savannahs early hominins occupied might have appeared thanks to a spate
of wildfires 8 million years ago — which might in turn be linked to a
nearby supernova
He adds that the technique will improve measurements
of astronomical distances, which build on the distances
of nearby objects such as M33 to estimate the distances to other «standard candles» farther away, such as
supernovae.
In the early 2000s, when looking for other objects in a
nearby galaxy, he and his colleagues captured an image filled with the echoing light
of three known
supernovas.
Shortly after a burst
of neutrinos from a
nearby supernova, the detector could direct astronomers to zero in on a few degrees
of sky.
In that case, faraway
supernovas (which we see as they were billions
of years ago, when the growth was more rapid) would have accumulated redshift more quickly relative to their distance than
nearby ones.
Galactic Ice Age Threat When a colleague asked him how a
nearby supernova blast might affect life on Earth, astrophysicist Nir Shaviv
of the Hebrew University
of Jerusalem thought he knew what to expect: a lot
of mutations from radiation.
Now, using precise chemical measurements
of seafloor rock and moon samples, scientists have shown that
nearby supernovas rained down radioactive iron and potentially influenced life on Earth.
Most such explosions are thought to have an identical intrinsic brightness, which Sandage and his colleagues have found by measuring the distances
of two
nearby galaxies that have spawned type Ia
supernovae.
Rob Beswick, a co-author
of the research paper from the University
of Manchester's Jodrell Bank Centre for Astrophysics added: «The explosion
of a Type Ia
supernova is a rare event in the
nearby Universe.
Supernova explosions in older,
nearby galaxies, says Lee, may have fertilized the nascent Milky Way — and in particular its center — with some
of the heavy elements we now find here.
According to a summary
of Barstow's talk released by the Royal Astronomical Society, the most probable explanation for the missing gas is that the area was swept clear
of material by a
nearby star that went
supernova within the last few million years.
Two
nearby supernovae explosions may have increased cancer rates and changed the behaviour
of early humans - but that's a pretty big may
Nearby, large stars erupt in cataclysmic
supernova explosions, sparking additional emissions from gas heated to millions
of degrees.
When our solar system was nothing but a cloud
of gas and dust, what was likely a shock wave from a
nearby supernova bounced up against it and caused it to collapse.
A direct comparison can thus be made, Hoscheit says, between the «cosmic» determination
of the Hubble Constant and the «local» determination derived from observations
of light from relatively
nearby supernovae.
Two previously undetected molecules, formylium (HCO +) and sulphur monoxide (SO), were found in the cooling aftermath
of Supernova 1987A, located 163,000 light years away in a
nearby neighbour
of our own Milky Way galaxy.
Each stretches tens
of light - years across and three are associated with
nearby supernova remnants.
No, it was one
of the things I was doing, but my main project was working on the robotic
nearby -
supernova search.
Part
of the Large Magellanic Cloud, a
nearby galaxy, has significantly more huge stars than we would expect to see, which could mean there are more
supernovae and black holes all over.
By measuring about 2,400 Cepheid stars in 19
nearby galaxies and comparing the apparent brightness
of both types
of stars, they accurately determined the true brightness
of the Type Ia
supernovae.
«We have found a remarkably large dust mass concentrated in the central part
of the ejecta from a relatively young and
nearby supernova,» said Remy Indebetouw, an astronomer at the National Radio Astronomy Observatory (NRAO) and the University
of Virginia, both in Charlottesville, USA.
Other discoveries in the Milky Way detailed in the special edition include the sharpest image yet
of a gamma ray source — a
nearby supernova remnant — which will enable researchers to study this object at finer scale than before — and three new «gamma ray shells» that are possibly examples
of a new type
of supernova remnant.
«We believe that the Solar System received an extra slug
of radioactive aluminum and iron from a
nearby supernova explosion at the time Vesta was forming,» explains Russell.
«The formation
of our own Sun and planets probably was heavily influenced, if not triggered, by a
nearby supernova explosion,» Lockman said.
A new study challenges the idea that a
nearby supernova forced the formation
of our solar system.
Type Ia
supernovae are fairly rare in the
nearby Universe and represent the explosion
of at least one white dwarf star in a binary system.
They made their best measurement to date in a recent study
of a
supernova first seen 27 years ago in a
nearby galaxy.
(iii) Far - infrared spectroscopy
of dust and ice features will address uncertainties in the mass and composition
of dust in galaxies, and the contributions
of supernovae to the interstellar dust budget will be quantified by photometry and monitoring
of supernova remnants in
nearby galaxies.
By comparing the observed brightness
of both types
of stars in those
nearby galaxies, the astronomers could then accurately measure their true brightness and therefore calculate distances to roughly 300 Type Ia
supernovae in far - flung galaxies.
The youngest stars in the galactic region surrounding around the Solar Neighborhood are associated with «subgroup B1»
of the Pleiades (M 45) stellar moving group, and astronomers hypothesize that the more massive stars born in this group may have already exploded as 20 or so
supernovae over the past 10 to 20 million years as the entire group
of stars moved through a
nearby region
of the Local Bubble (Berghoefer and Breitschwerdt, 2002).
After a
nearby sun goes
supernova, an astrophysicist puts together a desperate plan to shield the earth from the destrutive burst
of radiation.
GCRs are modulated by both solar magnetic field, which is largely unpredictable in strength except for generalities associated with 11 - year sunspot cycle and is also modulated by unpredictable events like
nearby supernovas, and by more predictable very very long slow changes in intensity due to the solar system traversing spiral arms
of our galaxy and wandering above and below the galactic plane in cycles lasting tens and hundreds
of millions
of years.