In the Sky This Week – December 18, 2018
Venus shines so brightly in the southeastern predawn sky, you can practically read by it! Jupiter makes its reappearance this week, joining Mercury, Venus and the star Spica.
Jupiter, Mercury, Venus and Spica in the eastern predawn sky - Dec. 18, 2018. Credit: Stellarium / Bob Trembley.
Mars is high in southern sky after sunset all week; the waxing gibbous Moon appears to the east of Mars on Dec. 18th.
The Moon and Mars high in the south-southeastern sky after sunset - Dec. 18, 2018. Credit: Stellarium / Bob Trembley.
The star Altair is now the "evening star" to the west at dusk; Saturn has almost vanished into the glare of the Sun.
Saturn very low in the southwestern sky at dusk on Dec. 18, 2018. Credit: Stellarium / Bob Trembley.
The Moon appears very near the star Aldebaran high in the western sky around 3:30 AM on Dec. 21st.
The Moon very near the star Aldebaran at 3:35 AM on Dec. 21, 2018. Credit: Stellarium / Bob Trembley.
On Christmas Eve, the waning gibbous Moon will appear in the eastern sky after sunset.
The Moon hight in the eastern sky near midnight on Dec. 24, 2018. Credit: Stellarium / Bob Trembley.
Observing Target: M1 - The Crab Nebula
M1, the Crab Nebula, is a supernova remnant located in the constellation of Taurus. The supernova was so bright in 1054 that it could be seen during the day for nearly a month; the supernova was documented by astronomers in several countries.
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| X-Ray: Chandra | Ultraviolet: ASTRO-1 | Visible: DSS | Visible: Color VLT |
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| Near-Infrared: 2MASS | Mid-Infrared: Spitzer | Far-Infrared: IRAS | Radio: NRAO |
Images from http://coolcosmos.ipac.caltech.edu/cosmic_classroom/multiwavelength_astronomy/multiwavelength_museum/m1.html
Location of M1 - the Crab Nebula. Credit: Stellarium / Bob Trembley.
The Moon
The Moon is a waxing gibbous - visible to the southeast in early evening, up for most of the night. The full Moon occurs on Dec. 22nd - rising at sunset, high in the sky around midnight, and visible all night. After the 22nd, the Moon will be a waning gibbous - rising after sunset, high in the sky after midnight, visible to the southwest after sunrise.
The Moon from Dec. 18-24, 2018. Visualizations by Ernie Wright.
The Sun
A bright region of coronal loop activity appears near the Sun's equator, but no sunspot is associated with it; the Sun as been spot-free for 2 days. Large coronal holes continue to remain open at both poles.
SpaceWeather.com says "The solar cycle is at low ebb. Today marks the 208th day in 2018 that the sun has been without spots, doubling the number of spotless days in 2017. The count won't be able to double again in 2019; there aren't enough days in the year! However, we can expect a further deepening of Solar Minimum in the year ahead with, literally, hundreds of spotless days to come."
Several small prominences have appeared on the Sun's limb over the last couple days - one loop (lower right) and several short-lived pillars, but no "OH WOWs" like happened last week.
The solar wind speed is 411.4 km/sec (↓), with a density of 6.5 protons/cm3 (↑).
Animated LASCO C2 Coronograph showing the solar corona above the Sun's limb (the white circle).
You 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.
Asteroids
Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT)
|
Miss Distance
|
Velocity (km/s)
|
Diameter (m)
|
| 2018 XM2 |
2018-Dec-12
|
14 LD
|
12.9
|
31
|
| 2018 XT4 |
2018-Dec-12
|
14.6 LD
|
5.1
|
18
|
| 2018 XL1 |
2018-Dec-12
|
2.4 LD
|
6.2
|
15
|
| 2018 XJ1 |
2018-Dec-13
|
5.6 LD
|
6.3
|
18
|
| 2018 XF4 |
2018-Dec-13
|
7.6 LD
|
14.6
|
34
|
| 2018 XZ4 |
2018-Dec-13
|
12 LD
|
10
|
81
|
| 2015 XX169 |
2018-Dec-13
|
17 LD
|
5.8
|
12
|
| 2018 XE2 |
2018-Dec-14
|
10.7 LD
|
21.1
|
39
|
| 2018 XB5 |
2018-Dec-14
|
7 LD
|
15.2
|
51
|
| 2018 XG4 |
2018-Dec-15
|
2.7 LD
|
7.8
|
11
|
| 2018 VO9 |
2018-Dec-15
|
2.6 LD
|
2.9
|
15
|
| 2018 XH1 |
2018-Dec-15
|
11.6 LD
|
6.7
|
25
|
| 2018 XS4 |
2018-Dec-16
|
2.8 LD
|
8.6
|
32
|
| 2018 XR4 |
2018-Dec-17
|
5.3 LD
|
11.4
|
15
|
| 2018 XC4 |
2018-Dec-21
|
1.6 LD
|
7.8
|
20
|
| 2017 XQ60 |
2018-Dec-21
|
11.3 LD
|
15.6
|
47
|
| 163899 |
2018-Dec-22
|
7.4 LD
|
6.2
|
1232
|
| 418849 |
2018-Dec-23
|
16.6 LD
|
17.6
|
269
|
| 2018 XN5 |
2018-Dec-24
|
3 LD
|
6.4
|
26
|
| 2018 XE4 |
2018-Dec-26
|
5.4 LD
|
9.4
|
18
|
| 2014 AD16 |
2019-Jan-04
|
12.9 LD
|
9.4
|
12
|
| 2018 XO4 |
2019-Jan-06
|
7.9 LD
|
4
|
30
|
| 2016 AZ8 |
2019-Jan-07
|
11.6 LD
|
9.1
|
224
|
| 2013 YM2 |
2019-Jan-09
|
7.3 LD
|
4.3
|
20
|
| 2018 XN |
2019-Jan-14
|
11.9 LD
|
5.6
|
59
|
| 2013 CW32 |
2019-Jan-29
|
13.9 LD
|
16.4
|
148
|
| 2013 RV9 |
2019-Feb-06
|
17.9 LD
|
5.9
|
68
|
| 2017 PV25 |
2019-Feb-12
|
7.3 LD
|
6.1
|
43
|
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com
Near-Earth objects (NEOs) discovered this month: 85, this year: 1929, all time: 19328.
Potentially hazardous asteroids: 1936 (as of Nov. 20, 2018)
Minor Planets discovered: 789,069 (as of Oct. 30, 2018)
Fireballs
On Dec. 17, 2018, the NASA All Sky Fireball Network reported 14 fireballs.
(9 sporadics, 2 Quadrantids, 2 sigma Hydrids, 1 Comae Berenicid)
In this diagram of the inner solar system, all of the fireball orbits from Dec. 17, 2018 intersect at a single point--Earth. Source: Spaceweather.com
Watch this meteor go behind the roof and then wait for it. A very interesting fireball from Church Crookham pic.twitter.com/Z5hq99tZ5G
— UK Meteor Network (@UKMeteorNetwork) December 17, 2018
Comets
Comet 46P/Wirtanen made its closest approach to Earth on Dec. 17th. Social media has been flooded with images.
Geminids, Pleiades, comet 46P/Wirtanen... can it get any better?? The clouds moved away at the @OOCC_IAC to give us an incredible show with hundreds of meteors falling over our heads. These are some of the brightest meteors captured in this field over 2 hours @TheUniverse_TM pic.twitter.com/vECBBJpQj6
— Antonio Martin-Carrillo (@antmarcarr) December 16, 2018
This weekend, Wirtanen became one of the closest comets to pass Earth in decades — and #NASAMarshall caught it as it flew by in this 120-second exposure.
Learn more about Comet 46P/Wirtanen >> https://t.co/eoLnJC7DP7 pic.twitter.com/hp3tSNsBsZ
— NASA Marshall (@NASA_Marshall) December 17, 2018
A comet called 46P/Wirtanen is giving Earth an unusually good view of its greenish glow this week. If weather allows, it will be visible until Dec. 22.https://t.co/EDdzo3AxH1
— NPR (@NPR) December 17, 2018
The Solar System
This is the position of the planets and a couple spacecraft in the solar system.
Position of the planets in the inner solar system, Dec. 18, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Position of the planets in the middle solar system, Dec. 18, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Comet 67P/Churyumov–Gerasimenko continues it's slow crawl by the planet Jupiter!
Comet 67P/Churyumov–Gerasimenko near Jupiter, Dec. 18, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Check out NASA's Interactive Solar System Orrery at: https://solarsystem.nasa.gov - click on the animated Orrery icon to launch the browser app.
It's kinda like NASA Eyes on the Solar System LITE, but for the browser; it can be used on computers where you cannot install the full Eyes client app.
Note: The Orrery is a WebGL browser app, and its performance is better on systems with hardware-accelerated graphics.
Spacecraft
OSIRIS-REx - Maneuvering around Asteroid Bennu
I've been at Bennu for two weeks now and the adventure is just getting started.
Mostly, I've been perfecting the flip turn - in space, not the swimming pool - and working on my other precision maneuvers.Here are details on my activities since arrival: https://t.co/Ygc94cgXEz pic.twitter.com/XZ7wKl78rH
— NASA's OSIRIS-REx (@OSIRISREx) December 17, 2018
Mars InSight - Prepares to Deploy Seismometer
Easy does it...
Who knew that practicing the claw game would come in handy for exploring #Mars? I’ve got a grip on my seismometer and am preparing to set it down. https://t.co/tjr8tfaCg5 pic.twitter.com/IsOAlXfiUt
— NASA InSight (@NASAInSight) December 18, 2018
Parker Solar Probe - Views the Sun's Corona Closer than any Spacecraft Before!
It's #SunDay! ☀️ This new view of the Sun's corona — a dynamic part of the solar atmosphere — was captured by #ParkerSolarProbe when it was just 16.9 million miles from the Sun, much closer than any spacecraft has ever gone before. https://t.co/kec0t4mey5 pic.twitter.com/omExgpMyvX
— NASA Sun & Space (@NASASun) December 16, 2018
Dec. 24th is 50th Anniversary of Apollo 8 Orbiting the Moon!
Launched on December 21, 1968, Apollo 8 became the first piloted spacecraft to leave low Earth orbit, reach the Moon, orbit it, and return safely to Earth.
Recreation of the iconic "Earthrise" image taken by Apollo 8's William Anders, using image data from the Lunar Reconnaissance Orbiter (LRO), with an added model of the Apollo 8 spacecraft. Visualization by Ernie Wright.
-Data from the NASA Exoplanet Archive
Apps used for this post:
NASA Eyes on the Solar System: an immersive 3D solar system and space mission simulator - free for the PC /MAC.
I maintain the unofficial NASA Eyes Facebook page.
Stellarium: a free open source planetarium app for PC/MAC/Linux. It's a great tool for planning observing sessions.
2018 is NASA's 60th Anniversary!