Hundreds of New Gravitational Lenses Discovered to Help Study the Distant Universe

These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)
These two columns show side-by-side comparisons of gravitational lens candidates imaged by the ground-based Dark Energy Camera Legacy Survey (color) and the Hubble Space Telescope (black and white). (Credit: Dark Energy Camera Legacy Survey, Hubble Space Telescope)

General relativity tells us that everything, even light, is affected by the mass of an object. When a beam of light passes near a large mass, its path is deflected. This shift in the direction of light is known as gravitational lensing, and it was one of the first confirmed effects of Einstein’s theory.

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New observations show that the Universe might not be expanding at the same rate in all directions

How cosmic expansion is measured. Credit: NASA, ESA and A. Feild (STScI)

When we look at the world around us, we see patterns. The Sun rises and sets. The seasons cycle through the year. The constellations drift across the night sky. As we’ve studied these patterns, we’ve developed scientific laws and theories that help us understand the cosmos. While our theories are powerful, they are still rooted in some fundamental assumptions. One of these is that the laws of physics are the same everywhere. This is known as cosmic isotropy, and it allows us to compare what we see in the lab with what we see light-years away.

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The Chemicals That Make Up Exploding Stars Could Help Explain Away Dark Energy

An illustration of cosmic expansion. Credit: NASA's Goddard Space Flight Center Conceptual Image Lab

Astronomers have a dark energy problem. On the one hand, we’ve known for years that the universe is not just expanding, but accelerating. There seems to be a dark energy that drives cosmic expansion. On the other hand, when we measure cosmic expansion in different ways we get values that don’t quite agree. Some methods cluster around a higher value for dark energy, while other methods cluster around a lower one. On the gripping hand, something will need to give if we are to solve this mystery.

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WFIRST Passes an Important Milestone, it’s Time to Begin Development and Testing

This graphic shows a simulation of a WFIRST observation of M31, also known as the Andromeda galaxy. Hubble used more than 650 hours to image areas outlined in blue. Using WFIRST, covering the entire galaxy would take only three hours. Credits: DSS, R. Gendle, NASA, GSFC, ASU, STScI, B. F. Williams

Soon, astronomers and astrophysicists will have more observing power than they know what to do with. Not only will the James Webb Space Telescope one day, sometime in the next couple years, we hope, if all goes well, and if the coronavirus doesn’t delay it again, launch and begin operations. But another powerful NASA space telescope called WFIRST has passed an important stage, and is one step closer to reality.

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There’s a new method to measure the expansion rate of the Universe, but it doesn’t resolve the Crisis in Cosmology

The venerable Hubble Space Telescope. After 30 years, it's still a productive scientific workhorse. Image Credit: NASA/ESA

In a recent post I wrote about a study that argued dark energy isn’t needed to explain the redshifts of distant supernovae. I also mentioned we shouldn’t rule out dark energy quite yet, because there are several independent measures of cosmic expansion that don’t require supernovae. Sure enough, a new study has measured cosmic expansion without all that mucking about with supernovae. The study confirms dark energy, but it also raises a few questions.

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This Simulation Shows what We’ll be Able to See with WFIRST

Credits: NASA's Goddard Space Flight Center

When it takes to space in 2025, the Wide-Field Infrared Survey Telescope (WFIRST) will be the most powerful observatory ever deployed, succeeding the venerable Hubble and Spitzer space telescopes. Relying on a unique combination of high resolution with a wide field of view, WFIRST will be able to capture the equivalent of 100 Hubble-quality images with a single shot and survey the night sky with 1,000 times the speed.

In preparation for this momentous event, astronomers at NASA’s Goddard Space Flight Center have been running simulations to demonstrate what the WFIRST will be able to see so they can plan their observations. To give viewers a preview of what this would look like, NASA’s Goddard Space Flight Center has shared a video that simulates the WFIRST conducting a survey of the neighboring Andromeda Galaxy (M31).

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New Research Casts A Shadow On The Existence Of Dark Energy

The cosmic distance ladder for measuring galactic distances.
The cosmic distance ladder for measuring galactic distances. Credit: NASA,ESA, A. Feild (STScI), and A. Riess (STScI/JHU)

The universe is expanding. When we look in all directions, we see distant galaxies speeding away from us, their light redshifted due to cosmic expansion. This has been known since 1929 when Edwin Hubble calcuated the relation between a galaxy’s distance and its redshift. Then in the late 1990s, two studies of distant supernovae found that the expansion of the universe is accelerating. Something, some dark energy, must be driving cosmic expansion.

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A Fifth Fundamental Force Could Really Exist, But We Haven’t Found It Yet

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

The universe is governed by four fundamental forces: gravity, electromagnetism, and the strong and weak nuclear forces. These forces drive the motion and behavior of everything we see around us. At least that’s what we think. But over the past several years there’s been increasing evidence of a fifth fundamental force. New research hasn’t discovered this fifth force, but it does show that we still don’t fully understand these cosmic forces.

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New Telescope Instrument Will Watch the Sky with 5,000 Eyes

DESI's 5000 spectroscopic "eyes" can cover an area of sky about 38 times larger than that of the full moon, as seen in this overlay of DESI's focal plane on the night sky (top). Each one of these robotically controlled eyes can fix a fiber-optic cable on a single object to gather its light. Credit: DESI Collaboration

Dark Energy is the mysterious force driving the expansion of the Universe. We don’t know what dark energy is, even though it makes up about 68% of the Universe. And the expansion is accelerating, which only adds to the mystery.

A new instrument called the Dark Energy Spectroscopic Instrument (DESI) will study dark energy. It’s doing so with 5,000 new robotic “eyes.”

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