The distance between Mars and Saturn in the southern predawn sky continues to grow with each passing morning. Jupiter is slowly making its way towards the southwest.
Southern predawn sky, Apr. 10 2018. Credit: Stellarium / Bob Trembley.Venus is low in the western sky near sunset, getting slightly higher with each evening.
Venus in the western sky shortly at 8:30 PM, Apr. 10, 2018. The yellow circles show the change in position of Venus over the next week. Credit: Stellarium / Bob Trembley.At midnight, Ursa Major is almost directly overhead; the “Big Dipper” is an asterism in Ursa Major – a prominent pattern or group of stars, typically having a popular name but smaller than a constellation. The Big Dipper can be used to “star-hop” to other stars and constellations all over the sky. The first star-hop I can remember learning was following the handle of the dipper to Arcturus, and on to Spica.
The sky overhead at midnight, Apr. 11, 2018, “star-hopping” from the “Big Dipper” asterism to the stars Arcturus and Spica. Credit: Stellarium / Bob Trembley.The Moon
The Moon Apr. 10-16 2018. Visualizations by Ernie WrightThe Moon is a waning crescent visible in the southeastern predawn sky, and traveling westward across the southern sky after dawn. The new Moon will occur late April 15th / early April 16th.
The Sun
The Sun has been spot-free for 9 days. There is a coronal hole at the Sun’s south pole, and one along the equator. SpaceWeather.com says: “NOAA forecasters say there is a 55% chance of minor G1-class geomagnetic storms on April 10th and 11th as a stream of solar wind gently buffets Earth’s magnetic field. The gaseous material is flowing from a wide hole in the sun’s atmosphere. Arctic sky watchers should be alert for auroras mixed with spring twilight.”
The solar wind speed is 522km/sec, with a density of 8.0 protons/cm3. – the densest I’ve seen the solar wind since I started reporting it!
The Sun’s chromosphere had only a few prominences the last couple days; you can see some bright coronal activity boiling-up near the Sun’s equator in this video:
Here’s another view of the activity in Sun’s corona:
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 GG |
2018-Apr-11
|
4.7 LD
|
13.9
|
44
|
| 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
|
| 2018 GH |
2018-Apr-25
|
14.6 LD
|
10.7
|
93
|
| 2013 US3 |
2018-Apr-29
|
10.1 LD
|
7.7
|
214
|
| 2018 FV4 |
2018-Apr-29
|
17.7 LD
|
6.5
|
59
|
| 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
Near-Earth objects discovered this month: 11, this year: 494, all time: 18045. As of April 10, 2018 there are 1882 known potentially hazardous asteroids.
Meteor Showers
The Lyrids Meteor shower runs from April 16-25, peaking April 21-22. More info next week.
Fireballs
On Apr 9, 2018, the NASA All Sky Fireball Network reported 3 fireballs.
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth.The Solar System
This is the position of the planets in the solar system:
Position of the planets in the solar system, Apr. 10, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.
Position of the planets in the solar system, Apr. 10, 2018 – alternate view. Credit: NASA Eyes on the Solar System / Bob Trembley.The Kepler Spacecraft
The Kepler exoplanet-hunting spacecraft has discovered thousands of planets orbiting stars in the vicinity of our Sun. Launched in 2009 on a 2-year mission, Kepler exoplanet discoveries started pouring-in! Until, disaster – three of Kepler’s four reaction wheels failed, hobbling the spacecraft as it was unable to point steadily at its target.
Mission engineers devised an ingenious method of using the solar wind to help keep the spacecraft pointed properly; the mission was extended in 2013, and the spacecraft resumed its hunt for exoplanets. Unfortunately, Kepler will soon run out of maneuvering propellant, effectively ending its historic mission.
Kepler exoplanet-hunting spacecraft . Credit: NASA Eyes on the Solar System / Bob Trembley.The Eyes on Exoplanets module within NASA’s Eyes on the Solar System app allows you to explore exoplanet systems that the Kepler spacecraft discovered.
NASA Eyes on Exoplanets: an interactive app that let’s you explore exoplanet systems discovered by the Kepler exoplanet-hunting spacecraft . Credit: NASA Eyes on the Solar System / Bob Trembley.Using Eyes on Exoplanets, you can zoom-in to exoplanet systems and get information on the host star and planetary system, see the system’s habitable zone, and compare the exoplanet system with our solar system.
Exoplanet system K2-138 simulated in NASA Eyes on Exoplanets. 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.
