The past couple days have certainly been a “voyage of discovery” for me. It started when I saw this tweet showing a massive release of energy from the Milky Way’s central black hole: Sagittarius A*.
The outburst took place over the short span of two and a half hours! WOW and then some! I stopped everything I was doing and went upstairs to show my wife, who also said WOW! I showed the tweet to some members of the Warren Astronomical Society at last Sunday’s Perseid Party at Stargate Observatory – they said WOW too… and then they cajoled me into presenting something about it at the W.A.S. meeting Thursday night – so go me!
Dr. Do was incredibly informative with his answers to a multitude of questions to his original tweet – a couple of them made me laugh out loud! I followed him on Twitter.
I then started with what I thought was going to be a “simple” search of the interwebs on Sagittarius A*… BOY did that turn into a trip down the rabbit-hole! There is an imperial boatload of articles, papers and resources about that black hole; it would take me days (if not weeks) to become comfortably conversant on the subject… I’m including some of the interesting things I found in this post.
The Moon appears near Saturn in the southern sky after sunset on August 13th. A reader asked me what the (x4) he sometimes saw on the images of the Moon I create for this section were – I use the app Stellarium to create images for my “In the Sky” posts; Stellarium allows you to magnify the size of the Moon so you can see it better, otherwise, unless you zoom WAYYY in you can hardly see the disk of the Moon. If you DO zoom in, you can’t fit very many constellations in the sky, so there’s a trade-off… Below are images of the same patch of sky with the Moon scaled and unscaled.
The full Moon appears in the southwestern sky before sunrise on August 15th.
The full Moon in the southwestern sky before sunrise on August 15th. Credit: Stellarium / Bob Trembley.The waning gibbous Moon is pretty lonely in the eastern sky at midnight on August 19th.
The Moon in the eastern sky at midnight on August 19th. Credit: Stellarium / Bob Trembley.The Moon is high in the southern sky around sunrise on August 19th,
The Moon high in the southern sky before sunrise on August 19th. Credit: Stellarium / Bob Trembley.Mercury is heading away from us in its orbit, and appears lower in the eastern predawn sky each morning this week.
Mercury low in the eastern predawn sky on August 14th. Credit: Stellarium / Bob Trembley.
Sagittarius A*
“I can’t see you, but I know you’re there…” – Genesis, All In A Mouse’s Night
I’m totally cheating here – you and your amateur telescope don’t have any hope of seeing the black hole in the core of the galaxy… but you can point to where it is!
Location of Sagittarius A* in the southern sky after sunset this week. Credit: Stellarium / Bob Trembley.These guys, however… they CAN see it! The lasers coming out of the telescopes are part of the telescope’s adaptive optics system.
Here’s a very cool zoom to Sgr A*, and animation of the stars orbiting it.
https://youtu.be/C0YCWziAPng
Coincidentally, the science fiction story I’m currently listening to on audio has the main characters in a spacecraft, in very close proximity to Sgr A*!
The Moon is a waxing gibbous, visible to the southeast in early evening, up for most of the night.
The full Moon occurs on August 15th, rising at sunset, visible high in the sky around midnight, and up all night.
After August 15th, the Moon will be a waning gibbous, rising after sunset, visible high in the sky after midnight, and visible to the southwest after sunrise.
The Moon from Aug. 13-19, 2019. Visualizations by Ernie Wright / NASA’s Scientific Visualization Studio.Moon News
The Sun has been spot-free for 6 days. Both the Sun’s poles have large coronal holes, the north hole is has been huge for weeks!
One prominence gave a great show for several hours during the afternoon of August 12!
https://www.facebook.com/photo.php?fbid=10219504083853635&set=gm.2595140127163982&type=3&theater&ifg=1
The solar wind speed is 452.4 km/sec (↓), with a density of 2.4 protons/cm3 (↑) at 1300 UT.
Animated LASCO C2 Coronograph showing the solar corona above the Sun’s limb (the white circle). Credit: NASA/JPL-CaltechYou can create your own time-lapse movies of the Sun here: AIA/HMI Browse Data.
You can browse all the SDO images of the Sun from 2010 to the present here: Browse SDO archive.
Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT)
|
Miss Distance
|
Velocity (km/s)
|
Diameter (m)
|
| 454094 |
2019-Aug-12
|
17 LD
|
8.2
|
148
|
| 2019 PX |
2019-Aug-12
|
19.6 LD
|
12
|
35
|
| 2019 PJ |
2019-Aug-16
|
8.8 LD
|
14.2
|
59
|
| 2018 PN22 |
2019-Aug-17
|
17.1 LD
|
2.3
|
11
|
| 2019 PK |
2019-Aug-18
|
11 LD
|
7.4
|
30
|
| 2016 PD1 |
2019-Aug-26
|
11.3 LD
|
5.9
|
65
|
| 2002 JR100 |
2019-Aug-27
|
19.4 LD
|
8.4
|
49
|
| 2019 OU1 |
2019-Aug-28
|
2.7 LD
|
13
|
95
|
| 2019 OF2 |
2019-Sep-03
|
18.3 LD
|
10.7
|
53
|
| 2018 DE1 |
2019-Sep-03
|
12.7 LD
|
6.6
|
28
|
| 2019 GT3 |
2019-Sep-06
|
19.5 LD
|
13.6
|
227
|
| 2010 RM82 |
2019-Sep-13
|
18.2 LD
|
14.6
|
23
|
| 2013 CV83 |
2019-Sep-13
|
15.7 LD
|
13.1
|
62
|
| 504800 |
2019-Sep-14
|
13.9 LD
|
14.4
|
155
|
| 467317 |
2019-Sep-14
|
13.9 LD
|
6.4
|
389
|
| 2019 JF1 |
2019-Sep-16
|
11.2 LD
|
4.3
|
61
|
| 2018 FU1 |
2019-Sep-16
|
18.4 LD
|
4.7
|
16
|
| 2017 SL16 |
2019-Sep-21
|
7.9 LD
|
6.5
|
25
|
| 2017 SM21 |
2019-Sep-21
|
11.5 LD
|
9.6
|
20
|
| 523934 |
2019-Sep-24
|
10.9 LD
|
22.3
|
257
|
| 2017 KP27 |
2019-Sep-26
|
6.2 LD
|
4.8
|
25
|
| 2006 QV89 |
2019-Sep-27
|
18.1 LD
|
4.1
|
31
|
| 2018 FK5 |
2019-Oct-01
|
13.3 LD
|
10.5
|
8
|
| 2018 LG4 |
2019-Oct-02
|
13.8 LD
|
8.1
|
12
|
| 2017 TJ4 |
2019-Oct-05
|
13.5 LD
|
8.9
|
32
|
Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Red highlighted entries are asteroids that either pass very close, or very large with high relative velocities to the Earth. Table from SpaceWeather.com
Potentially hazardous asteroids: 1983 (last updated May 8, 2019)
Minor Planets discovered: 796,541
On Aug. 12, 2019, the NASA All Sky Fireball Network reported 116 fireballs.
(76 Perseids, 38 sporadics, 1 Northern delta Aquariid, 1 Southern delta Aquariid)
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.comFireball & Meteor News:
This is the position of the planets and a couple bodies in the solar system:
Solar System News – Jupiter Gets Hit, Again!
OSIRIS-REx Asteroid Sample Return Mission – Final Four Sample Site Candidates
LightSail2 Solar Sail – Raises Orbit Around Earth Using Sunlight
Parker Solar Probe – Into its Second Year
Landsat – Images Siberian Fires
Climate
Data from the NASA Exoplanet Archive
Exoplanet Artwork by Bob Trembley
In my travels in SpaceEngine, I found a (hypothetical) system in a satellite galaxy of our Milky Way galaxy containing a gas giant with several moons. The moon I selected was tidally-locked to its gas giant parent – so the giant always hung at the same spot on the horizon. I took several screenshots from the same location – that I named my “camping spot,” running time forward through an entire day. The landscape displayed interesting differences depending on the lighting, and I couldn’t decide which image I wanted to show, so I put them ALL into a gallery:
[gallery type=”slideshow” size=”large” ids=”https://www.vaticanobservatory.org/wp-content/uploads/2019/08/Camping-Spot-Contact.jpg|Camping Spot – Cont
