Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The moon is front and center during a total solar eclipse

24.07.2017

In the lead-up to a total solar eclipse, most of the attention is on the sun, but Earth's moon also has a starring role.

"A total eclipse is a dance with three partners: the moon, the sun and Earth," said Richard Vondrak, a lunar scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It can only happen when there is an exquisite alignment of the moon and the sun in our sky."


In the lead-up to a total solar eclipse, most of the attention is on the sun, but Earth's moon also has a starring role.

Credit: NASA's Goddard Space flight Center/SVS

During this type of eclipse, the moon completely hides the face of the sun for a few minutes, offering a rare opportunity to glimpse the pearly white halo of the solar corona, or faint outer atmosphere. This requires nearly perfect alignment of the moon and the sun, and the apparent size of the moon in the sky must match the apparent size of the sun.

On average, a total solar eclipse occurs about every 18 months somewhere on Earth, although at any particular location, it happens much less often.

The total eclipse on Aug. 21, 2017, will be visible within a 70-mile-wide path that will cross 14 states in the continental U.S. from Oregon to South Carolina. Along this path of totality, the umbra, or dark inner shadow, of the moon will travel at speeds of almost 3,000 miles per hour in western Oregon to 1,500 miles per hour in South Carolina.

In eclipse maps, the umbra is often depicted as a dark circle or oval racing across the landscape. But a detailed visualization created for this year's eclipse reveals that the shape is more like an irregular polygon with slightly curved edges, and it changes as the shadow moves along the path of totality.

"With this new visualization, we can represent the umbral shadow with more accuracy by accounting for the influence of elevation at different points on Earth, as well as the way light rays stream through lunar valleys along the moon's ragged edge," said NASA visualizer Ernie Wright at Goddard.

This unprecedented level of detail was achieved by coupling 3-D mapping of the moon's surface, done by NASA's Lunar Reconnaissance Orbiter, or LRO, with Earth elevation information from several datasets.

LRO's mapping of the lunar terrain also makes it possible to predict very accurately when and where the brilliant flashes of light called Baily's Beads or the diamond-ring effect will occur. These intense spots appear along the edge of the darkened disk just before totality, and again just afterward, produced by sunlight peeking through valleys along the uneven rim of the moon.

In the very distant future, the spectacular shows put on by total solar eclipses will cease. That's because the moon is, on average, slowly receding from Earth at a rate of about 1-1/2 inches, or 4 centimeters, per year. Once the moon moves far enough away, its apparent size in the sky will be too small to cover the sun completely.

"Over time, the number and frequency of total solar eclipses will decrease," said Vondrak. "About 600 million years from now, Earth will experience the beauty and drama of a total solar eclipse for the last time."

###

NASA's Goddard Space Flight Center in Greenbelt, Md.

For more information about the upcoming 2017 solar eclipse, visit: https://eclipse2017.nasa.gov

For more information about NASA's Lunar Reconnaissance Orbiter, visit: http://www.nasa.gov/lro

Video link: https://youtu.be/jxanWTR8-yM

Elizabeth Zubritsky | EurekAlert!

More articles from Physics and Astronomy:

nachricht First evidence on the source of extragalactic particles
13.07.2018 | Technische Universität München

nachricht Simpler interferometer can fine tune even the quickest pulses of light
12.07.2018 | University of Rochester

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Research finds new molecular structures in boron-based nanoclusters

13.07.2018 | Materials Sciences

Algae Have Land Genes

13.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>