Mars continues its retrograde motion towards Saturn, as Jupiter moves slowly towards the west in the southern predawn sky.
Southern predawn sky, Mar. 20, 2018. Credit: Stellarium / Bob Trembley.A thin waxing crescent Moon joins Mercury and Venus in the western sky at dusk on March 20th; Mercury is getting dimmer each passing evening.
Mercury and Venus in the western sky shortly after 8:00 PM, Mar. 20, 2018. Credit: Stellarium / Bob Trembley.The bright stars Deneb and Altair are in the east as Mars and Saturn rise early in the morning sky.
Eastern sky at 4:15 AM, Mar. 20, 2018. Credit: Stellarium / Bob Trembley.
The Moon
The Moon Mar 20-26 2018. Visualizations by Ernie WrightThe Moon is a waxing crescent visible in the west near sunset. The Moon will be at first quarter on March 25th, and afterwards it will be a waxing gibbous – this whole week will be great for observing the Moon with a telescope!
The Sun
The Sun had a small spot last week, but has been spot-free for a day now. There is coronal hole at the Sun’s south pole with a tendril stretching north past the equator.
The solar wind speed is 449 km/sec, with a density of 5.0 protons/cm3. SpaceWeather.com says “NOAA forecasters say there is a 55% chance of G1-class geomagnetic storms on March 22nd when the solar wind currently blowing around Earth is expected to intensify. Arctic auroras are likely on the first nights of northern spring.”
The Sun’s chromosphere had a couple small prominences that lasted for several days – look at the 4:00 o’clock position on the Sun’s disk in the image below.
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.
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Asteroids
Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT)
|
Miss Distance
|
Velocity (km/s)
|
Diameter (m)
|
| 2018 EV1 |
2018-Mar-22
|
7.8 LD
|
11.3
|
29
|
| 2018 DH1 |
2018-Mar-27
|
9.2 LD
|
14.4
|
224
|
| 2016 SR2 |
2018-Mar-28
|
18.7 LD
|
7.3
|
20
|
| 2018 FB |
2018-Mar-29
|
4.9 LD
|
8.5
|
65
|
| 2010 GD35 |
2018-Mar-31
|
15.5 LD
|
11.6
|
45
|
| 2018 EM4 |
2018-Apr-01
|
6.2 LD
|
6.2
|
29
|
| 2004 FG29 |
2018-Apr-02
|
4 LD
|
14.9
|
22
|
| 2018 ER1 |
2018-Apr-02
|
15.6 LD
|
4
|
26
|
| 2018 EB |
2018-Apr-04
|
10.4 LD
|
15.1
|
162
|
| 363599 |
2018-Apr-12
|
19.3 LD
|
24.5
|
224
|
| 2014 UR |
2018-Apr-14
|
9.3 LD
|
4.4
|
17
|
| 2016 JP |
2018-Apr-20
|
12 LD
|
12.7
|
214
|
| 2012 XL16 |
2018-Apr-23
|
15.8 LD
|
6.1
|
28
|
| 2013 US3 |
2018-Apr-29
|
10.1 LD
|
7.7
|
214
|
| 2002 JR100 |
2018-Apr-29
|
10.8 LD
|
7.7
|
49
|
| 1999 FN19 |
2018-May-07
|
9.7 LD
|
5.7
|
118
|
| 2016 JQ5 |
2018-May-08
|
6.3 LD
|
10.4
|
9
|
| 388945 |
2018-May-09
|
6.5 LD
|
9
|
295
|
| 1999 LK1 |
2018-May-15
|
13.3 LD
|
10
|
141
|
Notes: LD means “Lunar Distance.” 1 LD = 384,401 km, the distance between Earth and the Moon. Table from SpaceWeather.com
As of March 20, 2018 there are 1882 known potentially hazardous asteroids.
Fireballs
On Mar. 19, 2018, the NASA All Sky Fireball Network reported 8 fireballs.
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). Credit: NOOA/SpaceWeather.comThe Solar System
This is the position of the planets in the solar system:
Position of the planets in the solar system, Mar. 20, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Position of the planets in the solar system, Mar. 20, 2018 – alternate view. Credit: NASA Eyes on the Solar System / Bob Trembley.Apps used for this post:
Stellarium: a free open source planetarium app for PC/MAC/Linux. It’s a great tool for planning observing sessions.
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.
