Perseid Meteor Shower 2017

 

Just after moonrise on August 12 this grain of cosmic sand fell by the sea, its momentary flash part of the annual Perseid Meteor Shower. To create the Perseid meteors, dust along the orbit of periodic comet Swift-Tuttle is swept up by planet Earth.

Perseid Meteor Shower 2017

The cometary debris plows through the atmosphere at nearly 60 kilometers per second and is quickly vaporized at altitudes of 100 kilometers or so. Perseid meteors are often bright and colorful, like the one captured in this sea and night skyscape.

Against starry sky and faint Milky Way the serene view looks south and west across the Adriatic Sea, from the moonlit Dalmatian coast toward the island of Brac.

Image Credit & CopyrightTamas Ladanyi (TWAN), NASA

Perseid meteors from the 2016 meteor shower

Perseid Meteor Shower 2016

Normally bright and colorful, the Perseid shower meteors are produced by dust swept up by planet Earth from the orbit of Comet Swift-Tuttle. They streak from a radiant in Perseus, above the horizon in clear predawn skies.

Frames used in this composite view capture bright Perseid meteors from the 2016 meteor shower set against a starry background along the Milky Way, with even the faint Andromeda Galaxy just above center.

In the foreground, astronomers of all ages have gathered on a hill above the Slovakian village of Vrchtepla.

Image Credit & CopyrightPetr Horálek

New Horizons Flies Over Charon Pluto Moon

 

The New Horizons spacecraft flies over Charon a Pluto Moon in 2015 July. The images recorded allowed for a digital reconstruction of much of Charon’s surface, further enabling the creation of fictitious flights over Charon created from this data.

Video credit: NASA, JHUAPL, SwRI, P. Schenk & J. Blackwell (LPI)

This minute-long, time-lapse video is shown with vertical heights and colors of surface features digitally enhanced. Your journey begins over a wide chasm that divides different types of Charon’s landscapes, a chasm that might have formed when Charon froze through.

You soon turn north and fly over a colorful depression dubbed Mordor that, one hypothesis holds, is an unusual remnant from an ancient impact. The voyage continues over an alien landscape rich with never-before-seen craters, mountains, and crevices.

The robotic New Horizons spacecraft has now been targeted at Kuiper Belt object 2014 MU 69, which it should zoom past on New Year’s Day 2019.

Charon, also known as (134340) Pluto I is the largest of the five known natural satellites of the dwarf planet Pluto. It was discovered in 1978 at the United States Naval Observatory in Washington, D.C., using photographic plates taken at the United States Naval Observatory Flagstaff Station (NOFS).

It is a very large moon in comparison to its parent body. Its gravitational influence is more powerful than that of Pluto. In September 2016, astronomers announced that the reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be essential ingredients of life.

Produced from methane, nitrogen and related gases released from the atmosphere of Pluto and transferred over about 19,000 km (12,000 mi) distance to the orbiting moon.

The New Horizons spacecraft is the only probe that has visited the Pluto system. It approached Charon to within 27,000 km (17,000 mi) in 2015.

Charon and Pluto orbit each other every 6.387 days. The two objects are gravitationally locked to one another, so each keeps the same face towards the other.

This is a case of mutual tidal locking, as compared to that of the Earth and the Moon, where the Moon always shows the same face to Earth, but not vice versa. The average distance between Charon and Pluto is 19,570 kilometers (12,160 mi). (See Below)

Pluto-Charon_System

 

Milky Way and Exploding Meteor

Next weekend the Perseid Meteor Shower reaches its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth’s atmosphere.

These grains were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle’s orbit, and are typically the most active meteor shower of the year.

Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute. This year’s Perseids peak nearly a week after full Moon, and so some faint meteors will be lost to the lunar skyglow.

Meteor showers in general are best be seen from a relaxing position, away from lights. Featured here is a meteor caught exploding during the 2015 Perseids above Austria next to the central band of our Milky Way Galaxy.

Credit: NASA, APOD, vanderHoeven

JunoCam Stormy Cloud Towers on Jupiter

JunoCam Stormy Cloud Towers on Jupiter

 

JunoCam Stormy Cloud Towers on Jupiter
Click image and zoom in to view in full resolution.

Small bright clouds dot Jupiter’s entire south tropical zone in this image acquired by JunoCam. Taken on NASA’s Juno spacecraft on May 19, 2017, at an altitude of 7,990 miles (12,858 kilometers).

Although the bright clouds appear tiny in this vast Jovian cloudscape, they actually are cloud towers. At roughly 30 miles (50 kilometers) wide and 30 miles (50 kilometers) high that cast shadows on the clouds below.

Clouds on Jupiter

On Jupiter, clouds this high are almost certainly composed of water and/or ammonia ice. They may be sources of lightning. This is the first time so many cloud towers have been visible. This is possibly because the late-afternoon lighting is particularly good at this geometry.

JunoCam’s raw images are available at www.missionjuno.swri.edu/junocam for the public to peruse and process into image products.

NASA’s Jet Propulsion Laboratory manages the Juno mission.  The principal investigator is Scott Bolton, of Southwest Research Institute in San Antonio.

Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center. Located in Huntsville, Alabama, for NASA’s Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. Caltech in Pasadena, California, manages JPL for NASA.

More information about Juno is online at http://www.nasa.gov/juno and http://missionjuno.swri.edu.

Image Credit:NASA/SWRI/MSSS/Gerald Eichstadt/Sean Doran