Dark Energy - NASA Goddard

Roman will help illuminate the dark energy puzzle by using multiple methods to explore how the universe has evolved throughout cosmic history.

The universe is ballooning outward as space itself stretches, perhaps under the force of a mysterious cosmic pressure known as dark energy. 

Galaxies like our own are hurtling away from each other at an ever-increasing clip, swept apart by an unseen power. All the stars in our galaxy, the particles in our planet, and even the atoms in our bodies would immediately fly apart if they weren't held together by stronger forces. 

Though weak on small scales, dark energy dominates across vast stretches of the cosmos. It makes up about 68% of the universe's total contents, but so far we don't know much more about it. In some ways, the mystery has gotten even more confusing as we've learned more — the latest and most thorough observations seem to show that the strange pressure is shifting over time, holding the fate of the universe in the balance. NASA’s Nancy Grace Roman Space Telescope will usher in a new era of dark energy exploration, potentially solving the mystery of its true nature.  

Until the 20th century, most scientists believed the universe was static, remaining essentially unchanged throughout eternity. Gradually, astronomers discovered that not only is our universe expanding — its expansion is inexplicably speeding up, possibly due to a mysterious forced dubbed dark energy. The next wave of dark energy missions, including NASA's Nancy Grace Roman Space Telescope, will search for clues by mapping galaxies and watching how they move, grow, and bend light to track expansion more precisely over longer stretches of cosmic time.

NASA's Goddard Space Flight Center

Illuminating Dark Energy

To figure out whether dark energy truly exists (and, if so, what it actually is), scientists are studying how it behaves. But it seems the more we learn about the mystery, the more perplexing it becomes. Recent results hint that dark energy may be changing over time in ways we don't yet understand. 

The next wave of dark energy missions will search for clues by mapping galaxies and watching how they move, grow, and bend light to track expansion more precisely over longer stretches of cosmic time. 

Together, Roman, Rubin, and Euclid will usher in a new era of dark energy discovery 

When Roman opens its eyes to the cosmos, its large field of view and crisp infrared vision will help scientists collect a treasure trove of valuable data. The mission will use several different measurement techniques to test our model of the universe between early and modern periods, with each method cross-checking the others.  

The recent discovery that dark energy may be evolving could mean that dark energy began influencing the universe’s expansion earlier than scientists thought. Roman will explore cosmic expansion during earlier epochs, providing unique information that remains shrouded from other telescopes. 

This could confirm whether dark energy is really changing over time and offer clues to explain such unexpected behavior.  

Source: Dark Energy - NASA Science

New findings overturn 100-year-old assumption about common bacteria in the lungs - Biology Cell & Microbiology

Credit: Pixabay/CC0 Public Domain

The human body is teeming with more than 35 trillion bacteria, coexisting in microbiomes inside the gut, mouth, lungs, skin and urogenital tract. While it's now clear these microbes are associated with health and disease, scientists have only begun to uncover the full scale of their biology and functions.

In a striking example of just how much is still unknown, a new University of Michigan study overturns a 100-year-old assumption about one common bacterial resident of the lungs, Prevotella melaninogenica. The research is published in the Journal of Bacteriology.

The lab led by Ariangela Kozik, Ph.D., assistant professor of internal medicine at U-M Medical School and assistant professor of molecular, cellular and developmental biology at U-M, is interested in Prevotella because the bacteria are commonly found in the respiratory tract and reportedly associated with all manner of chronic conditions, yet are also found in healthy people. The genus is also widely thought to be an obligate anaerobe, incapable of surviving in the presence of oxygen.

What, they wondered, is it doing in the lungs?

Testing a lung microbe's limits

Kozik, an asthma researcher, notes that Prevotella are found in differing amounts inside the respiratory tract in both healthy people and people with asthma and COPD, accounting for roughly 10% of microbial populations in healthy lungs and up to 13%, on average, among individuals with respiratory disease.

To unravel this paradox, Kozik's team subjected cultures of P. melaninogenica to increasing percentages of oxygen, comparing the rates of growth and survival.

They found that the upper threshold for growth was between 5–8% oxygen, and the bacteria could briefly survive oxygen levels as high as 21%.

Furthermore, the study found, using a new real-time sensor platform and RNA sequencing, that Prevotella appear to be consuming oxygen and dealing with oxidative stress and DNA damage differently than other aerobic bacteria.

"Prevotella has all of these mechanisms to allow it to survive in oxygenated environments that previously were not appreciated for this organism at all, changing what we thought we knew," said Kozik.

The ability to exist in the presence of oxygen may lie along a spectrum and not be as clear-cut as scientists have traditionally defined, she notes.

Questions beyond oxygen tolerance

Kozik and her lab hope to next interrogate how the immune system responds to Prevotella and dive deeper into lung bacteriology to understand specifically how these microbes affect the body.

"We need to work to look at the bacterial community and ask, how does this community currently function? What metabolites are they making, what signals are they sending to the immune system? How's the immune system responding to it? How does this activity differ in health versus in the context of chronic lung diseases?" said Kozik.

This deeper understanding of the body's various microbiomes could help drive more targeted therapies, she adds.

"Those kinds of questions about the relationships between bacteria and the body are a big black box right now." 

Provided by University of Michigan 

by University of Michigan

edited by Sadie Harley, reviewed by Robert Egan 

Source: New findings overturn 100-year-old assumption about common bacteria in the lungs