Tag Archives: Dark Energy

NASA Space Place – The Heavyweight Champion Of The Cosmos

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in February, 2015.

By Dr. Ethan Siegel

2013february2_spaceplaceAs crazy as it once seemed, we once assumed that the Earth was the largest thing in all the universe. 2,500 years ago, the Greek philosopher Anaxagoras was ridiculed for suggesting that the Sun might be even larger than the Peloponnesus peninsula, about 16% of modern-day Greece. Today, we know that planets are dwarfed by stars, which themselves are bound together by the billions or even trillions into galaxies.

But gravitationally bound structures extend far beyond galaxies, which themselves can bind together into massive clusters across the cosmos. While dark energy may be driving most galaxy clusters apart from one another, preventing our local group from falling into the Virgo Cluster, for example, on occasion, huge galaxy clusters can merge, forming the largest gravitationally bound structures in the universe.

Take the “El Gordo” galaxy cluster, catalogued as ACT-CL J0102-4915. It’s the largest known galaxy cluster in the distant universe. A galaxy like the Milky Way might contain a few hundred billion stars and up to just over a trillion (1012) solar masses worth of matter, the El Gordo cluster has an estimated mass of 3 × 1015 solar masses, or 3,000 times as much as our own galaxy! The way we’ve figured this out is fascinating. By seeing how the shapes of background galaxies are distorted into more elliptical-than-average shapes along a particular set of axes, we can reconstruct how much mass is present in the cluster: a phenomenon known as weak gravitational lensing.

That reconstruction is shown in blue, but doesn’t match up with where the X-rays are, which are shown in pink! This is because, when galaxy clusters collide, the neutral gas inside heats up to emit X-rays, but the individual galaxies (mostly) and dark matter (completely) pass through one another, resulting in a displacement of the cluster’s mass from its center. This has been observed before in objects like the Bullet Cluster, but El Gordo is much younger and farther away. At 10 billion light-years distant, the light reaching us now was emitted more than 7 billion years ago, when the universe was less than half its present age.

It’s a good thing, too, because about 6 billion years ago, the universe began accelerating, meaning that El Gordo just might be the largest cosmic heavyweight of all. There’s still more universe left to explore, but for right now, this is the heavyweight champion of the distant universe!

Learn more about “El Gordo” here: www.nasa.gov/press/2014/april/nasa-hubble-team-finds-monster-el-gordo-galaxy-cluster-bigger-than-thought/

El Gordo is certainly huge, but what about really tiny galaxies? Kids can learn about satellite galaxies at NASA’s Space Place spaceplace.nasa.gov/satellite-galaxies/.


Image credit: NASA, ESA, J. Jee (UC Davis), J. Hughes (Rutgers U.), F. Menanteau (Rutgers U. and UIUC), C. Sifon (Leiden Observatory), R. Mandelbum (Carnegie Mellon U.), L. Barrientos (Universidad Catolica de Chile), and K. Ng (UC Davis). X-rays are shown in pink from Chandra; the overall matter density is shown in blue, from lensing derived from the Hubble space telescope. 10 billion light-years distant, El Gordo is the most massive galaxy cluster ever found.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

TACNY Junior Cafe Scientifique: “The Dark Side of the Universe”

Saturday – September 20, 9:30-11:00am

Milton J Rubenstein Museum of Science & Technology – Syracuse, NY

View Larger Map

We’re back!! Stuff that most of us have seen is made of atoms, tiny particles that cause scientists headaches and lead to inventions like microwaves. However, current observations beyond our planet have led to astonishing mysteries. It seems most of the universe is made of things called dark matter and dark energy. These strange substances are not like anything we have encountered and they imply bizarre consequences for the past and eventual fate of our universe. Dr. Scott Watson will discuss both the evidence and the consequences of nature living on the dark side of the universe.

People interested in learning more about dark matter are invited to attend the free Junior Cafe presentation on Saturday, September 20, from 9:30 a.m. to 11 a.m. at the Milton J. Rubenstein Museum of Science and Technology (MOST) in Syracuse’s Armory Square. Walk-ins are welcome, but we ask that people RSVP by emailing jrcafe@tacny.org by September 17, 2014.


Watson _small001Prof. Watson is an assistant professor at Syracuse University, working in the fields of theoretical particle physics and cosmology. He received his doctorate in physics from Brown University under the supervision of Robert Brandenberger. He held research positions at the University of Toronto and the University of Michigan before joining the faculty at Syracuse in 2010. He also holds visiting positions at Cornell University and with Stephen Hawking’s group at Cambridge University in England.

Prof. Watson’s research is focused on fundamental questions related to the origin of the universe and its ultimate fate. How did the universe begin? What is its eventual fate? Do atoms represent all of the stuff making up the universe, or do things like dark energy and dark matter control our ultimate fate? Questions like these are at the center of Prof. Watson’s research. Present theories suggest that the seeds for the growth of structures like galaxies and eventually life resulted from the quantum behavior of particles and fields in the very early universe — when it was less than a fraction of a second old. Such a description requires a quantum understanding of gravity with string theory being our leading candidate for such a theory. And so Prof. Watson’s research is also involved in establishing observational implications of string theory.

TACNY Junior Cafe Scientifique

TACNY Junior Cafe Scientifique, a program for middle-school students founded in 2005, features discussions about topics in the fields of science, technology, engineering and mathematics in an informal atmosphere and seeks to encourage students to consider careers in these areas. Students must be accompanied by an adult and can explore the MOST at no cost after the event.

Technology Alliance of Central New York

Founded in 1903 as the Technology Club of Syracuse, the nonprofit Technology Alliance of Central New York’s mission is to facilitate community awareness, appreciation, and education of technology; and to collaborate with like-minded organizations across Central New York.

For more information about TACNY, visit www.tacny.org.

NASA News Digest: Space Science For 22 July – 31 July 2014

Greetings fellow astrophiles,

The NASA News service provides up-to-date announcements of NASA policy, news events, and space science. A recent selection of space science articles are provided below, including direct links to the full announcements. Those interested in receiving these news announcements directly from NASA can subscribe to their service by sending an email to:


NASA’s Chandra X-Ray Observatory Celebrates 15th Anniversary

RELEASE 14-196 (Click here for the full article) – 22 July 2014

14_196_smallFifteen years ago, NASA’s Chandra X-ray Observatory was launched into space aboard the Space Shuttle Columbia. Since its deployment on July 23, 1999, Chandra has helped revolutionize our understanding of the universe through its unrivaled X-ray vision.

Chandra, one of NASA’s current “Great Observatories,” along with the Hubble Space Telescope and Spitzer Space Telescope, is specially designed to detect X-ray emission from hot and energetic regions of the universe.

With its superb sensitivity and resolution, Chandra has observed objects ranging from the closest planets and comets to the most distant known quasars. It has imaged the remains of exploded stars, or supernova remnants, observed the region around the supermassive black hole at the center of the Milky Way, and discovered black holes across the universe. Chandra also has made a major advance in the study of dark matter by tracing the separation of dark matter from normal matter in collisions between galaxy clusters. It also is contributing to research on the nature of dark energy.

Additional details, images and an animation are available at: www.ciclops.org/view_event/202
More information about Cassini is available at: www.nasa.gov/cassini and saturn.jpl.nasa.gov

Hubble Finds Three Surprisingly Dry Exoplanets

RELEASE 14-197 (Click here for the full article) – 24 July 2014

14_197_smallAstronomers using NASA’s Hubble Space Telescope have gone looking for water vapor in the atmospheres of three planets orbiting stars similar to the sun — and have come up nearly dry.
The three planets, known as HD 189733b, HD 209458b, and WASP-12b, are between 60 and 900 light-years away from Earth and were thought to be ideal candidates for detecting water vapor in their atmospheres because of their high temperatures where water turns into a measurable vapor.

These so-called “hot Jupiters” are so close to their star they have temperatures between 1,500 and 4,000 degrees Fahrenheit, however, the planets were found to have only one-tenth to one one-thousandth the amount of water predicted by standard planet-formation theories.

For images and more information about Hubble, visit: www.nasa.gov/hubble and hubblesite.org/news/2014/36

Cassini Spacecraft Reveals 101 Geysers and more on Icy Saturn Moon

RELEASE 14-203 (Click here for the full article) – 28 July 2014

14_203_smallScientists using mission data from NASA’s Cassini spacecraft have identified 101 distinct geysers erupting on Saturn’s icy moon Enceladus. Their analysis suggests it is possible for liquid water to reach from the moon’s underground sea all the way to its surface.

These findings, and clues to what powers the geyser eruptions, are presented in two articles published in the current online edition of the Astronomical Journal.

Over a period of almost seven years, Cassini’s cameras surveyed the south polar terrain of the small moon, a unique geological basin renowned for its four prominent “tiger stripe” fractures and the geysers of tiny icy particles and water vapor first sighted there nearly 10 years ago. The result of the survey is a map of 101 geysers, each erupting from one of the tiger stripe fractures, and the discovery that individual geysers are coincident with small hot spots. These relationships pointed the way to the geysers’ origin.

Additional details, images and an animation are available at: www.ciclops.org/view_event/202

More information about Cassini is available at: www.nasa.gov/cassini and saturn.jpl.nasa.gov

Hubble Shows Farthest Lensing Galaxy Yields Clues to Early Universe

RELEASE 14-205 (Click here for the full article) – 31 July 2014

14_205_smallAstronomers using NASA’s Hubble Space Telescope have unexpectedly discovered the most distant galaxy that acts as a cosmic magnifying glass. Seen here as it looked 9.6 billion years ago, this monster elliptical galaxy breaks the previous record-holder by 200 million years.

These “lensing” galaxies are so massive that their gravity bends, magnifies, and distorts light from objects behind it, a phenomenon called gravitational lensing. Finding one in such a small area of the sky is so rare that you would normally have to survey a region hundreds of times larger to find just one.

For images and more information about Hubble, visit: www.nasa.gov/hubble and hubblesite.org/news/2014/33

NASA’s Fermi Space Telescope Reveals New Source of Gamma Rays

RELEASE 14-209 (Click here for the full article) – 31 July 2014

14_209_smallObservations by NASA’s Fermi Gamma-ray Space Telescope of several stellar eruptions, called novae, firmly establish these relatively common outbursts almost always produce gamma rays, the most energetic form of light.

“There’s a saying that one is a fluke, two is a coincidence, and three is a class, and we’re now at four novae and counting with Fermi,” said Teddy Cheung, an astrophysicist at the Naval Research Laboratory in Washington, and the lead author of a paper reporting the findings in the Aug. 1 edition of the journal Science.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star caused by a thermonuclear explosion on the surface of a white dwarf, a compact star not much larger than Earth. Each nova explosion releases up to 100,000 times the annual energy output of our sun. Prior to Fermi, no one suspected these outbursts were capable of producing high-energy gamma rays, emission with energy levels millions of times greater than visible light and usually associated with far more powerful cosmic blasts.

For more information about Fermi, visit: www.nasa.gov/fermi