Category Archives: Astrophysics

Breaking the warp barrier for faster-than-light travel

Artistic impression of different spacecraft designs considering theoretical shapes of different kinds of “warp bubbles”.
CREDIT: E Lentz

Astrophysicist at Göttingen University discovers new theoretical hyper-fast soliton solutions

If travel to distant stars within an individual’s lifetime is going to be possible, a means of faster-than-light propulsion will have to be found. To date, even recent research about superluminal (faster-than-light) transport based on Einstein’s theory of general relativity would require vast amounts of hypothetical particles and states of matter that have “exotic” physical properties such as negative energy density. This type of matter either cannot currently be found or cannot be manufactured in viable quantities. In contrast, new research carried out at the University of Göttingen gets around this problem by constructing a new class of hyper-fast ‘solitons’ using sources with only positive energies that can enable travel at any speed. This reignites debate about the possibility of faster-than-light travel based on conventional physics. The research is published in the journal Classical and Quantum Gravity.

The author of the paper, Dr Erik Lentz, analysed existing research and discovered gaps in previous ‘warp drive’ studies. Lentz noticed that there existed yet-to-be explored configurations of space-time curvature organized into ‘solitons’ that have the potential to solve the puzzle while being physically viable. A soliton – in this context also informally referred to as a ‘warp bubble’ – is a compact wave that maintains its shape and moves at constant velocity. Lentz derived the Einstein equations for unexplored soliton configurations (where the space-time metric’s shift vector components obey a hyperbolic relation), finding that the altered space-time geometries could be formed in a way that worked even with conventional energy sources. In essence, the new method uses the very structure of space and time arranged in a soliton to provide a solution to faster-than-light travel, which – unlike other research – would only need sources with positive energy densities. No “exotic” negative energy densities needed.

If sufficient energy could be generated, the equations used in this research would allow space travel to Proxima Centauri, our nearest star, and back to Earth in years instead of decades or millennia. That means an individual could travel there and back within their lifetime. In comparison, the current rocket technology would take more than 50,000 years for a one-way journey. In addition, the solitons (warp bubbles) were configured to contain a region with minimal tidal forces such that the passing of time inside the soliton matches the time outside: an ideal environment for a spacecraft. This means there would not be the complications of the so-called “twin paradox” whereby one twin travelling near the speed of light would age much more slowly than the other twin who stayed on Earth: in fact, according to the recent equations both twins would be the same age when reunited.

“This work has moved the problem of faster-than-light travel one step away from theoretical research in fundamental physics and closer to engineering. The next step is to figure out how to bring down the astronomical amount of energy needed to within the range of today’s technologies, such as a large modern nuclear fission power plant. Then we can talk about building the first prototypes,” says Lentz.

Currently, the amount of energy required for this new type of space propulsion drive is still immense. Lentz explains, “The energy required for this drive travelling at light speed encompassing a spacecraft of 100 meters in radius is on the order of hundreds of times of the mass of the planet Jupiter. The energy savings would need to be drastic, of approximately 30 orders of magnitude to be in range of modern nuclear fission reactors.” He goes on to say: “Fortunately, several energy-saving mechanisms have been proposed in earlier research that can potentially lower the energy required by nearly 60 orders of magnitude.” Lentz is currently in the early-stages of determining if these methods can be modified, or if new mechanisms are needed to bring the energy required down to what is currently possible.

###

Original publication: Erik W Lentz, Breaking the Warp Barrier: Hyper-Fast Solitons in Einstein-Maxwell-Plasma Theory, Classical and Quantum Gravity, March 2021. DOI: 10.1088/1361-6382/abe692

SOURCE: EurekaAlert

Comet Catalina suggests comets delivered carbon to rocky planets

SW News Staff/Source

False color image of Comet C/2013 US10 (Catalina) based on data taken at the Lowell Discovery Telescope near Happy Jack, AZ with the Large Monolithic Imager on February 13, 2016. In this composite, stars show up as red, green, and blue artifacts, due to the comet’s motion on the sky during the image sequence. Credit: M.S.P. Kelley (University of Maryland)/S. Protopapa (Southwest Research Institute)/Lowell Discovery Telescope

MINNEAPOLIS / ST. PAUL (03/05/2021) — In early 2016, an icy visitor from the edge of our solar system hurtled past Earth. It briefly became visible to stargazers as Comet Catalina before it slingshotted past the Sun to disappear forevermore out of the solar system.

Among the many observatories that captured a view of this comet, which appeared near the Big Dipper, was the Stratospheric Observatory for Infrared Astronomy (SOFIA), NASA’s telescope on an airplane. Using one of its unique infrared instruments, SOFIA was able to pick out a familiar fingerprint within the dusty glow of the comet’s tail—carbon. 

Now this one-time visitor to our inner solar system is helping explain more about our own origins as it becomes apparent that comets like Catalina could have been an essential source of carbon on planets like Earth and Mars during the early formation of the solar system. 

New results from SOFIA, a joint project of NASA and the German Aerospace Center, were published in the Planetary Science Journal

“Carbon is key to learning about the origins of life,” said the paper’s lead author, Charles “Chick” Woodward, an astrophysicist and professor in the University of Minnesota Twin Cities Minnesota Institute of Astrophysics. “We’re still not sure if Earth could have trapped enough carbon on its own during its formation, so carbon-rich comets could have been an important source delivering this essential element that led to life as we know it.” 

Frozen in Time

Originating from the Oort Cloud at the farthest reaches of our solar system, Comet Catalina and others of its type have such long orbits that they arrive on our celestial doorstep relatively unaltered. This makes them effectively frozen in time, offering researchers rare opportunities to learn about the early solar system from which they come.

SOFIA’s infrared observations were able to capture the composition of the dust and gas as it evaporated off the comet, forming its tail. The observations showed that Comet Catalina is carbon-rich, suggesting that it formed in the outer regions of the primordial solar system, which held a reservoir of carbon that could have been important for seeding life. 

This illustration of a comet from the Oort Cloud as it passes through the inner solar system with dust and gas evaporating into its tail. SOFIA’s observations of Comet Catalina reveal that it’s carbon-rich, suggesting that comets delivered carbon to the terrestrial planets like Earth and Mars as they formed in the early solar system. Credit: NASA/SOFIA/ Lynette Cook

While carbon is a key ingredient of life, early Earth and other terrestrial planets of the inner solar system were so hot during their formation that elements like carbon were lost or depleted. While the cooler gas giants like Jupiter and Neptune could support carbon in the outer solar system, Jupiter’s jumbo size may have gravitationally blocked carbon from mixing back into the inner solar system. 

Primordial Mixing

So how did the inner rocky planets evolve into the carbon-rich worlds that they are today?

Researchers think that a slight change in Jupiter’s orbit allowed small, early precursors of comets to mix carbon from the outer regions into the inner regions, where it was incorporated into planets like Earth and Mars. 

Comet Catalina’s carbon-rich composition helps explain how planets that formed in the hot, carbon-poor regions of the early solar system evolved into planets with the life-supporting element.

“All terrestrial worlds are subject to impacts by comets and other small bodies, which carry carbon and other elements,” Woodward said. “We are getting closer to understanding exactly how these impacts on early planets may have catalyzed life.”

Observations of additional new comets are needed to learn if there are many other carbon-rich comets in the Oort Cloud, which would further support that comets delivered carbon and other life-supporting elements to the terrestrial planets. As the world’s largest airborne observatory, SOFIA’s mobility allows it to quickly observe newly discovered comets as they make a pass through the solar system. 

SOFIA is a joint project of NASA and the German Aerospace Center. NASA’s Ames Research Center in California’s Silicon Valley manages the SOFIA program, science, and mission operations in cooperation with the Universities Space Research Association, headquartered in Columbia, Maryland, and the German SOFIA Institute at the University of Stuttgart. The aircraft is maintained and operated by NASA’s Armstrong Flight Research Center Building 703, in Palmdale, California.

SOURCE: CSE.UMN.EDU

New data locates hundreds of millions of objects throughout space

Survey has mapped one-eighth of the skies, studying dark energy

This irregular dwarf galaxy, named IC 1613, and discovered through the Dark Energy Survey, contains some 100 million stars (bluish in this portrayal). It is a member of our Local Group of galaxy neighbors, a collection which also includes our Milky Way, the Andromeda spiral and the Magellanic clouds.Credit: DES/NOIRLab/NSF/AURA. Acknowledgments: Image processing: DES, Jen Miller (Gemini Observatory/NSF’s NOIRLab), Travis Rector (University of Alaska Anchorage), Mahdi Zamani & Davide de Martin

A longstanding project designed to study dark energy throughout the cosmos has released a second data set showing 300 million objects throughout space, one of the largest data releases of its kind. Combined with an initial release, the survey has now cataloged about 700 million objects in the universe.

The data was released by the Dark Energy Survey, an international collaboration of about 500 scientists from the U.S., Europe and South America, to map hundreds of millions of galaxies and thousands of supernovae in an attempt to understand more about dark energy, the force that is causing the universe to expand. The Ohio State University has played a primary role in the survey from the beginning.

The survey, started in 2013, has so far mapped about one-eighth of the skies.

The release was announced Friday, Jan. 15, at the American Astronomical Society’s annual meeting, held virtually this year.

Klaus Honscheid

“This release tells the world, ‘If you ever want to see any of these galaxies, here’s where they are and here’s what they look like,’ said Klaus Honscheid, a physics professor at Ohio State and member of Ohio State’s Center for Cosmology and Astroparticle Physics. “And people can use this info and do their own analysis – look for objects of a certain property or compare to theoretical models. This is really enabling a lot of people to do work now outside the DES collaboration.”

Last week’s release is the second from the Dark Energy Survey. The data builds on the 400 million objects cataloged in the survey’s previous data release, and improves on the first release by refining calibration techniques and including deeper combined images of the objects throughout space. That combination, scientists say, led to improved estimates of the amount and distribution of matter in the universe.

The data allows researchers to determine the size, shape and location of objects – most of them galaxies, but also quasars, stars, interstellar gas clouds and asteroids – throughout space, and to build a catalog of those objects

“These images combine data from the same locations in the skies – images of the same spot, multiple times,” said Ami Choi, co-convener of the DES science working group on weak gravitational lensing and a CCAPP fellow. “And it’s three-dimensional, so it allows us to build a map that looks deep into this one part of the universe.”

The new data should make it easier for astronomers, astrophysicists and cosmologists – both professional and amateur – to locate those objects in the night skies, and to build models around the distance those objects may have moved away from one another over time.

“The catalog contains these objects with their properties and their location, and anyone else who has this information and a big enough telescope can go look at the location we specified and repeat these observations,” Honscheid said.

The expansion of the universe is the key to understanding dark energy. Previous work has shown that the universe has been expanding since its birth some 13.8 billion years ago, and that for approximately the last 7 billion years the universe’s expansion is accelerating.

The next set of results from the survey is expected later this spring, said Jack Elvin-Poole, co-convener of the DES science working group on large scale structure and a CCAPP fellow.

Scientists at the Dark Energy Survey, including those at Ohio State, are still analyzing data released last week to discern what it might say about dark energy and the expansion of the universe. The data are online and available to the public; the survey’s scientists will make their analysis available after it is complete.

“We are very interested in cosmology – the history of the universe – so we are looking for these dark energy signatures in this data,” Honscheid said. “If you think about dark energy, it’s something that pulls the universe apart, that pushes objects further apart.”

The survey involves taking photographs of light produced by each object and analyzing the wavelengths of that light.

This analysis is built on a concept called “redshifting,” which gets its name from the way wavelengths of light lengthen as they travel through the expanding universe.

“The farther away something is in the universe, the longer its wavelength of light – and longer wavelengths appear red, while shorter wavelengths appear blue,” said Anna Porredon, a CCAPP fellow who worked on the survey. “Scientists who study the cosmos call that lengthening the redshift effect.”

There are a number of other researchers at Ohio State who have worked on the DES project, including David Weinberg, Paul Martini, Chris Hirata and Ashley Ross.

SOURCE:NEWS.OSU.EDU Credit: Laura Arenschield