What Drives Universe’s Expansion?

Astronomy experiments could soon test an idea developed by Albert Einstein almost exactly a century ago, scientists say.

Tests using advanced technology could resolve a longstanding puzzle over what is driving the accelerated expansion of the Universe.

Researchers have long sought to determine how the Universe’s accelerated expansion is being driven. Calculations in a new study could help to explain whether dark energy- as required by Einstein’s theory of general relativity — or a revised theory of gravity are responsible.

Einstein’s theory, which describes gravity as distortions of space and time, included a mathematical element known as a Cosmological Constant. Einstein originally introduced it to explain a static universe, but discarded his mathematical factor as a blunder after it was discovered that our Universe is expanding.

Research carried out two decades ago, however, showed that this expansion is accelerating, which suggests that Einstein’s Constant may still have a part to play in accounting for dark energy. Without dark energy, the acceleration implies a failure of Einstein’s theory of gravity across the largest distances in our Universe.

Scientists from the University of Edinburgh have discovered that the puzzle could be resolved by determining the speed of gravity in the cosmos from a study of gravitational waves -space-time ripples propagating through the universe.

The researchers’ calculations show that if gravitational waves are found to travel at the speed of light, this would rule out alternative gravity theories, with no dark energy, in support of Einstein’s Cosmological Constant. If however, their speed differs from that of light, then Einstein’s theory must be revised.

Such an experiment could be carried out by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US, whose twin detectors, 2000 miles apart, directly detected gravitational waves for the first time in 2015.

Experiments at the facilities planned for this year could resolve the question in time for the 100th anniversary of Einstein’s Constant.

The study, published in Physics Letters B, was supported by the UK Science Technology Facilities Council, the Swiss National Science Foundation, and the Portuguese Foundation of Science and Technology.

Dr Lucas Lombriser, of the University of Edinburgh’s School of Physics and Astronomy, said: “Recent direct gravitational wave detection has opened up a new observational window to our Universe. Our results give an impression of how this will guide us in solving one of the most fundamental problems in physics.”

Ancient Signals From The Early Universe

For the first time, theoretical physicists from the University of Basel have calculated the signal of specific gravitational wave sources that emerged fractions of a second after the Big Bang. The source of the signal is a long-lost cosmological phenomenon called “oscillon.” The journal Physical Review Letters has published the results.

Although Albert Einstein had already predicted the existence of gravitational waves, their existence was not actually proven until fall 2015, when highly sensitive detectors received the waves formed during the merging of two black holes. Gravitational waves are different from all other known waves. As they travel through the universe, they shrink and stretch the space-time continuum; in other words, they distort the geometry of space itself. Although all accelerating masses emit gravitational waves, these can only be measured when the mass is extremely large, as is the case with black holes or supernovas.

Gravitational waves transport information from the Big Bang

However, gravitational waves not only provide information on major astrophysical events of this kind but also offer an insight into the formation of the universe itself. In order to learn more about this stage of the universe, Prof. Stefan Antusch and his team from the Department of Physics at the University of Basel are conducting research into what is known as the stochastic background of gravitational waves. This background consists of gravitational waves from a large number of sources that overlap with one another, together yielding a broad spectrum of frequencies. The Basel-based physicists calculate predicted frequency ranges and intensities for the waves, which can then be tested in experiments.

A highly compressed universe

Shortly after the Big Bang, the universe we see today was still very small, dense, and hot. “Picture something about the size of a football,” Antusch explains. The whole universe was compressed into this very small space, and it was extremely turbulent. Modern cosmology assumes that at that time the universe was dominated by a particle known as the inflaton and its associated field.

Oscillons generate a powerful signal

The inflaton underwent intensive fluctuations, which had special properties. They formed clumps, for example, causing them to oscillate in localized regions of space. These regions are referred to as oscillons and can be imagined as standing waves. “Although the oscillons have long since ceased to exist, the gravitational waves they emitted are omnipresent — and we can use them to look further into the past than ever before,” says Antusch.

Using numerical simulations, the theoretical physicist and his team were able to calculate the shape of the oscillon’s signal, which was emitted just fractions of a second after the Big Bang. It appears as a pronounced peak in the otherwise rather broad spectrum of gravitational waves. “We would not have thought before our calculations that oscillons could produce such a strong signal at a specific frequency,” Antusch explains. Now, in a second step, experimental physicists must actually prove the signal’s existence using detectors.million years.”

Dwarf Star 200 Light Years Away Contains Life’s Building Blocks

Many scientists believe the Earth was dry when it first formed, and that the building blocks for life on our planet — carbon, nitrogen and water — appeared only later as a result of collisions with other objects in our solar system that had those elements.

Today, a UCLA-led team of scientists reports that it has discovered the existence of a white dwarf star whose atmosphere is rich in carbon and nitrogen, as well as in oxygen and hydrogen, the components of water. The white dwarf is approximately 200 light years from Earth and is located in the constellation Boötes.

Benjamin Zuckerman, a co-author of the research and a UCLA professor of astronomy, said the study presents evidence that the planetary system associated with the white dwarf contains materials that are the basic building blocks for life. And although the study focused on this particular star — known as WD 1425+540 — the fact that its planetary system shares characteristics with our solar system strongly suggests that other planetary systems would also.

“The findings indicate that some of life’s important preconditions are common in the universe,” Zuckerman said.

The scientists report that a minor planet in the planetary system was orbiting around the white dwarf, and its trajectory was somehow altered, perhaps by the gravitational pull of a planet in the same system. That change caused the minor planet to travel very close to the white dwarf, where the star’s strong gravitational field ripped the minor planet apart into gas and dust. Those remnants went into orbit around the white dwarf — much like the rings around Saturn, Zuckerman said — before eventually spiraling onto the star itself, bringing with them the building blocks for life.

The researchers think these events occurred relatively recently, perhaps in the past 100,000 years or so, said Edward Young, another co-author of the study and a UCLA professor of geochemistry and cosmochemistry. They estimate that approximately 30 percent of the minor planet’s mass was water and other ices, and approximately 70 percent was rocky material.

The research suggests that the minor planet is the first of what are likely many such analogs to objects in our solar system’s Kuiper belt. The Kuiper belt is an enormous cluster of small bodies like comets and minor planets located in the outer reaches of our solar system, beyond Neptune. Astronomers have long wondered whether other planetary systems have bodies with properties similar to those in the Kuiper belt, and the new study appears to confirm for the first time that one such body exists.

White dwarf stars are dense, burned-out remnants of normal stars. Their strong gravitational pull causes elements like carbon, oxygen and nitrogen to sink out of their atmospheres and into their interiors, where they cannot be detected by telescopes.

The research, published in the Astrophysical Journal Letters, describes how WD 1425+540 came to obtain carbon, nitrogen, oxygen and hydrogen. This is the first time a white dwarf with nitrogen has been discovered, and one of only a few known examples of white dwarfs that have been impacted by a rocky body that was rich in water ice.

“If there is water in Kuiper belt-like objects around other stars, as there now appears to be, then when rocky planets form they need not contain life’s ingredients,” said Siyi Xu, the study’s lead author, a postdoctoral scholar at the European Southern Observatory in Germany who earned her doctorate at UCLA.

“Now we’re seeing in a planetary system outside our solar system that there are minor planets where water, nitrogen and carbon are present in abundance, as in our solar system’s Kuiper belt,” Xu said. “If Earth obtained its water, nitrogen and carbon from the impact of such objects, then rocky planets in other planetary systems could also obtain their water, nitrogen and carbon this way.”

A rocky planet that forms relatively close to its star would likely be dry, Young said.

“We would like to know whether in other planetary systems Kuiper belts exist with large quantities of water that could be added to otherwise dry planets,” he said. “Our research suggests this is likely.”

According to Zuckerman, the study doesn’t settle the question of whether life in the universe is common.

“First you need an Earth-like world in its size, mass and at the proper distance from a star like our sun,” he said, adding that astronomers still haven’t found a planet that matches those criteria.

The researchers observed WD 1425+540 with the Keck Telescope in 2008 and 2014, and with the Hubble Space Telescope in 2014. They analyzed the chemical composition of its atmosphere using an instrument called a spectrometer, which breaks light into wavelengths. Spectrometers can be tuned to the wavelengths at which scientists know a given element emits and absorbs light; scientists can then determine the element’s presence by whether it emits or absorbs light of certain characteristic wavelengths. In the new study, the researchers saw the elements in the white dwarf’s atmosphere because they absorbed some of the background light from the white dwarf.

February 11th 2017 Penumbral Lunar Eclipse

An eclipse of the moon can only happen at full moon, when the Sun, Earth and moon line up, with Earth in the middle. There are three kinds of lunar eclipses: Total, Partial and Penumbral – At such times, Earth’s shadow falls on the moon creating a lunar eclipse. Lunar eclipse(s) develop at a minimum of two times – to a maximum of five times per year.

In a total eclipse of the moon, the inner part of Earth’s shadow, called the umbra, falls on the moon’s face. At mid-eclipse, the entire moon is in shadow, which mostly appear as shades of gray, and on occasion will appear as shades of reddish/gray.

In a partial lunar eclipse, the umbra appears to take a swath out of a circumference of the moon. The darken shadow grows larger, and then recedes, never reaching the total phase.

In a penumbral lunar eclipse, the diminished outer shadow of Earth falls on the moon’s face. This third kind of eclipse is more subtle and difficult to observe. It is absent of the darker shadow as in a partial eclipse. This eclipse stops short of presenting the dramatic minutes of totality. For those using simple field binoculars or moderate telescopes will be able to witness the transition. If there are clear skies and at the right geographical locations, you will be able to see the event with the naked eye.

NASA astrophysicist Fred Espenak, tells us about 35% of all eclipses are penumbral. Another 30% are partial eclipses, where it appears as if a darkened scoop has been taken out of the moon. And the final 35% go all the way to becoming total eclipses of the moon, a glorious event.

Black Hole Feeding Frenzy Breaks Records

A giant black hole ripped apart a nearby star and then continued to feed off its remains for close to a decade, according to research led by the University of New Hampshire. This black hole meal is more than 10 times longer than any other previous episode of a star’s death.

“We have witnessed a star’s spectacular and prolonged demise,” said Dacheng Lin, a research scientist at UNH’s Space Science Center and the study’s lead author. “Dozens of these so-called tidal disruption events have been detected since the 1990s, but none that remained bright for nearly as long as this one.”

Using data from a trio of orbiting X-ray telescopes, NASA’s Chandra X-ray Observatory and Swift Satellite as well as ESA’s XMM-Newton, researchers found evidence of a massive “tidal disruption event” (TDE). Tidal forces, due to the intense gravity from the black hole, can destroy an object — such as a star — that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inward, and is ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare.

These multiwavelength flares, which can be viewed by the satellites, help to study otherwise dormant massive back holes. Previous flares were short-lived, typically becoming very faint in a year, but this super-long X-ray flare has been persistently bright for close to a decade. The extraordinary long bright phase of this TDE means that either this was the most massive star ever to be torn apart during one of these events, or the first where a smaller star was completely torn apart.

The X-ray source containing this force-fed black hole, known by its abbreviated name of XJ1500+0154, is located in a small galaxy about 1.8 billion light years from Earth. The X-ray data also indicates that radiation from material surrounding this black hole has consistently surpassed the so-called Eddington limit, defined by a balance between the outward pressure of radiation from the hot gas and the inward pull of the gravity of the black hole.

The conclusion that supermassive black holes can grow, from TDEs and perhaps other means, at rates above those corresponding to the Eddington limit has important implications. Such rapid growth may help explain how supermassive black holes were able to reach masses about a billion times higher than the sun when the universe was only about a billion years old.

Based on the modeling by the researchers the black hole’s feeding supply should be significantly reduced in the next decade and begin to fade in the next several years.

Planet’s Atmospheric Oxygen Rose Through Glaciers

A University of Wyoming researcher contributed to a paper that determined a “Snowball Earth” event actually took place 100 million years earlier than previously projected, and a rise in the planet’s oxidation resulted from a number of different continents — including what is now Wyoming — that were once connected.

“Isotopic dating of the Ongeluk large igneous province, South Africa, revealed that the first Paleoproterozoic global glaciation and the first significant step change in atmospheric oxygenation likely occurred between 2,460 and 2,426 million years ago, approximately 100 million years earlier than previous estimates,” says Kevin Chamberlain, a UW research professor in the Department of Geology and Geophysics. “And the rise of atmospheric oxygen was not monotonic but, instead, was characterized by significant oscillations before irreversible oxygenation of the atmosphere 2,250 million years ago.”

Chamberlain is the second author of a paper, titled “Timing and Tempo of the Great Oxidation Event,” which appears in the Proceedings of the National Academy of Sciences (PNAS).

Ashley Gumsley, a doctoral student at Lund University in Lund, Sweden, is the paper’s lead author. Other contributors were from the Geological Survey of Canada in Ottawa; Swedish Museum of Natural History; University of Johannesburg, South Africa; and the University of California-Riverside.

The research relates to a period in Earth’s history about 2.45 billion years ago, when climate swung so extremely that the polar ice caps extended to the equator and Earth was a snowball, and the atmosphere was largely isolated from the hydrosphere, Chamberlain says. Recovery from this Snowball Earth led to the first and largest, rapid rise in oxygen content in the atmosphere, known as the Great Oxygenation Event (GOE), setting the stage for the dominance of aerobic life, he says.

A later, and better known, Snowball Earth period occurred at about 700 million years ago, and led to multicellular life in the Cambrian period, Chamberlain says. The events show there was not one event, but an oscillation of oxygen over time that led to Earth’s conditions today.

“So, both Snowball Earth periods had extreme impacts on the development of life,” he says. “It helps us understand the evolution of Earth and Earth’s atmosphere, and evolution of life, for that matter.”

Chamberlain’s contribution focuses on igneous rocks exposed in South Africa that record the existence of equatorial glaciers and contain chemical indicators for the rise of atmospheric oxygen. Chamberlain’s in situ method to determine the age of the rocks does not require removing baddeleyite crystals from the rock. This process allows for analysis of key samples with smaller crystals than previously allowed. Using a mass spectrometer, the age of the rocks is determined by measuring the buildup of lead from the radioactive decay of uranium, he says.

“The basic story had been worked out earlier by others, but our results have significantly refined the timing and duration of the ‘event,’ which is more of a transition actually,” Chamberlain explains. “With all the discussion of climate change in the present day, understanding how Earth responded and the effects on the atmosphere in the past may help us predict the future.”

Chamberlain points to a Wyoming connection in this research. From paleomagnetic data, many of the continents, at the time, including the basement rocks of Wyoming, were all connected into a single, large continent and situated near the equator. Other continents connected included parts of what are now Canada and South Africa. This situation is part of the trigger for the “Snowball Earth” conditions.

“There are glacial deposits exposed in the Medicine Bow Mountains and Sierra Madre that are from this same event,” he says.

These rocks, known as diamictites, have large drop stones that depress very fine-grained mudstone. The large stones dropped from the underside of glacial sheets as they spread out and melted over shallow seas, similar to sediments beneath the Ross sea ice sheet of Antarctica today.

“The fact that these sediments were at the equator at 2.45 billion years ago comes from the paleomagnetic data from associated igneous rocks,” Chamberlain says.

BREAKING NEWS: New Findings Illustrate Secondary Extended Solar Cycles Far Greater Danger than Previously Known

Based on a new study, space scientists at the University of Reading are predicting we are witness to the beginning of a longer-term solar cycle, which will exceed the better-known 11 year and 22 year cycles. Each cycle consist of a ‘solar minimum’ and ‘solar maximum’ measured by the number of sunspots during these periods – and the waxing and waning of charged particles produced by solar flares, coronal mass ejections, coronal holes, and charged filaments.

This research is produced by Dr Mathew Owens, from the University of Reading’s Meteorology department, and Co-author Professor Mike Lockwood FRS, University of Reading. Their paper was published in the journal ‘Scientific Reports’. “The magnetic activity of the Sun ebbs and flows in predictable cycles, but there is also evidence that it is due to plummet, possibly by the largest amount for 300 years”; said Owens.

As the Sun becomes less active, sunspots and coronal ejections will become less frequent. As this trend continues over time, the escalating reduction in solar wind has a direct causal effect on the layers of the Sun’s atmosphere. The most significant effect will be on the ‘heliosphere’ – which like Earth’s magnetic field, shields the Earth dangerous charged particles and radiation.

**I am working on the completion of this study – hope to have it published tomorrow. STAY TUNED…..