In the Sky This Week – July 30, 2019

I went outside this morning before sunrise to see the thin waning crescent Moon above the horizon – although it was clear overhead, clouds stubbornly clung to my eastern horizon, obscuring my view…

Very thin waning crescent Moon in the east-northeastern sky before sunrise on July 30th. Credit: Stellarium / Bob Trembley.

So I found this tweet with an image of the Moon I had wanted to see.

Saturn and Jupiter continue to make excellent observing targets in the southern sky after sunset.

Saturn and Jupiter high in the southern sky after sunset all week. Credit: Stellarium / Bob Trembley.

The Andromeda galaxy is visible in the east-northeastern sky around midnight.

Andromeda in the east-northeastern sky after sunset all week. Credit: Stellarium / Bob Trembley.

You can explore the Andromeda galaxy – and zoom waaaaaaay in here: [Link]

By the beginning of August, Mercury will be visible in the same patch of east-northeastern predawn sky.

Mercury low in the east-northeastern sky before sunrise on August 6th. Credit: Stellarium / Bob Trembley.

The waxing crescent Moon appears near the star Spica after sunset on August 5th.

The Moon near the star Spica on August 5th after sunset. Credit: Stellarium / Bob Trembley.

M 24 – The Small Sagittarius Cloud

Small Sagittarius Cloud/ Credit” Caustiche /Creative Commons

The Sagittarius Star Cloud (also known as Messier 24 and IC 4715) is a star cloud in the constellation of Sagittarius, approximately 600 light years wide, which was discovered by Charles Messier in 1764. It is sometimes known as the Small Sagittarius Star Cloud to distinguish it from the Great Sagittarius Star Cloud located to the north of Gamma Sagittarii and Delta Sagittarii.

The stars, clusters and other objects comprising M24 are part of the Sagittarius or Sagittarius-Carina arms of the Milky Way galaxy. Messier described M24 as a “large nebulosity containing many stars” and gave its dimensions as being some 1.5° across. Some sources, improperly, identify M24 as the faint cluster NGC 6603. The location of the Sagittarius Star Cloud is near the Omega Nebula (also known as M17) and open cluster Messier 18, north of M24. M24 is one of only three Messier objects that are not deep sky objects.

M24 fills a space of significant volume to a depth of 10,000 to 16,000 light-years. This is the most dense concentration of individual stars visible using binoculars, with around 1,000 stars visible within a single field of view. The star cloud can be seen visible when the Milky Way itself is visible as well. Without the dust and gas that conceals the Milky Way, M24 holds a collection of numerous kinds of stars that are placed along the Milky Way and through the galaxy’s obscuring band of interstellar dust. – Wikipedia

The Moon is a waning crescent, visible low to the east before sunrise.

The new Moon occurs on August 1^st.

After August 1st, the Moon will be a waxing crescent, v2isible toward the southwest in early evening.

The Moon from July 30-August 5, 2019. Visualizations by Ernie Wright / NASA’s Scientific Visualization Studio.

Moon News

The Sun has been spot-free for 7 days. SpaceWeather.com says “Earth is about to be strobed by three streams of solar wind–each flowing from a hole the sun’s atmosphere.” These coronal holes are clearly visible in the video below from NASA’s Solar Dynamics Observatory on July 29th ” The southern coronal hole seems to have reduced in size – the northern hole remains open and huge.

Some fantastic prominence activity over the last couple days gave solar photographers another chance to capture some great photos.

https://www.facebook.com/photo.php?fbid=10219389848237816&set=gm.2570443586300303&type=3&theater&ifg=1

The solar wind speed is 356.6 km/sec (↓), with a density of 2.9 protons/cm³ (↑).

Animated LASCO C2 Coronograph showing the solar corona above the Sun’s limb (the white circle). Credit: NASA/JPL-Caltech

Upcoming Earth-asteroid encounters:

Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com

On July 29, 2019, the NASA All Sky Fireball Network reported 29 fireballs.
(20 sporadics, 5 Perseids, 2 Southern delta Aquariids, 2 alpha Capricornids)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). From: Spaceweather.com

Fireball & Meteor News:

This is the position of the planets and a couple bodies in the solar system:

OSIRIS-REx Asteroid Sample Return Mission

Landsat

Climate

Data from the NASA Exoplanet Archive

PDS 70. CREDITS: ESO and S. Haffert (Leiden Observatory)

PDS 70 is only the second multi-planet system to be directly imaged. Through a combination of adaptive optics and data processing, astronomers were able to cancel out the light from the central star (marked by a white star) to reveal two orbiting exoplanets. PDS 70 b (lower left) weighs 4 to 17 times as much as Jupiter while PDS 70 c (upper right) weighs 1 to 10 times as much as Jupiter.

Exoplanet Artwork by Bob Trembley

Hypothetical Earthlike exoplanet in the Large Magellanic Cloud (LMC). Credit: SpaceEngine/Bob Trembley

a

Galaxy Mergers

These images reveal the final stage of a union between pairs of galactic nuclei in the messy cores of colliding galaxies. CREDITS: NASA, ESA, and M. Koss (Eureka Scientific, Inc.); Hubble image: NASA, ESA, and M. Koss (Eureka Scientific, Inc.); Keck images: W. M. Keck Observatory and M. Koss (Eureka Scientific, Inc.); Pan-STARRS images: Panoramic Survey Telescope and Rapid Response System and M. Koss (Eureka Scientific, Inc.)

The image at top left, taken by Hubble’s Wide Field Camera 3, shows the merging galaxy NGC 6240. A close-up of the two brilliant cores of this galactic union is shown at top right. This view, taken in infrared light, pierces the dense cloud of dust and gas encasing the two colliding galaxies and uncovers the active cores. The hefty black holes in these cores are growing quickly as they feast on gas kicked up by the galaxy merger. The black holes’ speedy growth occurs during the last 10 million to 20 million years of the merger.

Images of four other colliding galaxies, along with close-up views of their coalescing nuclei in the bright cores, are shown beneath the snapshots of NGC 6240. The images of the bright cores were taken in near-infrared light by the W. M. Keck Observatory in Hawaii, using adaptive optics to sharpen the view.

The reference images (left) of the merging galaxies were taken by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS).

The two nuclei in the Hubble and Keck Observatory photos are only about 3,000 light-years apart — a near-embrace in cosmic terms. If there are pairs of black holes, they will likely merge within the next 10 million years to form a more massive black hole.

These observations are part of the largest-ever survey of