This week, Mars continues its retrograde-motion conjunction with Saturn in the southern predawn sky.
Southern predawn sky, Apr. 2-9, 2018. Credit: Stellarium / Bob Trembley.Venus is low and bright in the western sky after sunset all week long.
Venus in the western sky shortly after 8:00 PM, Apr. 3, 2018. Credit: Stellarium / Bob Trembley.The Moon
The Moon Mar. 27-Apr. 2 2018. Visualizations by Ernie WrightThe Moon is a waning gibbous heading towards third-quarter this weekend. Afterwards, the Moon will be a waning crescent, visible during the morning hours.
The Sun
The Sun has been spot-free for 2 days. There are large coronal holes at both the Sun’s poles, and a smaller one is rotating into view along the Sun’s equator.
The solar wind speed is 401km/sec, with a density of 2.0 protons/cm3. The Sun’s chromosphere has prominences all over the place for the last couple days.
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 EB |
2018-Apr-04
|
10.4 LD
|
15.1
|
165
|
| 2018 FW4 |
2018-Apr-05
|
9.8 LD
|
11.6
|
35
|
| 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
|
| 2018 FV4 |
2018-Apr-29
|
17.7 LD
|
6.5
|
61
|
| 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
|
| 68347 |
2018-May-29
|
9.5 LD
|
13.3
|
389
|
| 2013 LE7 |
2018-May-31
|
17.8 LD
|
1.7
|
12
|
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 Apr 2, 2018, the NASA All Sky Fireball Network reported 5 fireballs.
China’s Tiangong-1 space station reentered the atmoshpere and pieces crashed into the Pacific ocean, thankfully avoiding any populated areas.
NW of Tahiti – it managed to miss the ‘spacecraft graveyard’ which is further south! pic.twitter.com/Sj4e42O7Dc
— Jonathan McDowell (@planet4589) April 2, 2018
Tiangong-1 Reentry simulated in Kerbal Space Program. Credit: Bob TrembleyThe Solar System
This is the position of the planets in the solar system:
Position of the planets in the solar system, Apr. 3, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Position of the planets in the solar system, Apr. 3, 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.
