Mars opposition happened last week with the Earth overtaking Mars in its orbit; the Earth will now pull ahead of Mars as the distance between the two planets increases over the next several months. Mars will slowly dim, and shrink in size in telescopes, but should still be a good observing target for several weeks.
Mars and Saturn are bright in the early morning sky to the south on July 31, 2018. The Moon also be visible in the early morning sky all week. Credit: Stellarium / Bob Trembley.Jupiter is in the southwestern sky at dusk and sets around 11:30 PM; Saturn is an excellent observing target all night long in the southern sky.
Jupiter and Saturn in the southern sky at 10:00 PM, July 31 2018. Credit: Stellarium / Bob Trembley.Jupiter continues a slow crawl towards the Venus in the west; Venus appears a bit lower in the western sky each evening.
Venus and Jupiter are in the southwestern sky at dusk, July 31, 2018. Credit: Stellarium / Bob Trembley.Southern Hemisphere:
From Montevideo, Uruguay, Venus is high in the west-northwestern sky at 5:00 PM on July 31 2018, and as you’ll note, it’s dark. Jupiter is VERY high in the northwestern sky.
From Montevideo, Uruguay, Venus is high in the west-northwestern sky at 5:00 PM July 31 2018. Jupiter appears in the northwestern sky, and is much higher than in the northern hemisphere.Mars is high in the eastern sky from Montevideo at 5:00 PM on July 31 2018, Saturn appearing much higher and opposite side from Mars as it appears in the northern hemisphere.
From Montevideo, Uruguay, Mars and Saturn are high in the eastern sky at 5:00 PM July 31 2018. Saturn appears much higher in the sky, and is on the opposite side from Mars than in the northern hemisphere.The Moon
The Moon is a waning gibbous, rising after dark and setting in the mid-morning. The Moon will be at third quarter on August 4th, setting around 12:30 PM. After the 4th the Moon will be a waning crescent, visible in the southeastern sky before sunrise.
The Moon from July 31-Aug. 6, 2018. Visualizations by Ernie WrightObserving Target: Mars
Mars is just about as close to Earth as it gets – I’m seeing several posts saying that Mars is closer to Earth than it’s been in 15 years. Even though Mars is experiencing a global dust storm, telescopes across the globe will be pointed at Mars, and photos will be taken. Even the Hubble Space Telescope is gazing at Mars:
Image of the week: @NASAHubble’s close-up view of the Mars dust storm. See details at https://t.co/zxNTGLIK1i
Now is a great time to see #Mars for yourself in the night sky. See where and when to look: https://t.co/arcHOPfSKA pic.twitter.com/PqxYjLn0oZ
— NASA Solar System (@NASASolarSystem) July 31, 2018
The Sun
The Sun as been spot-free for 9 days – an active region with some coronal loops activity is rotating into view. There is a HUGE coronal hole at the north pole, and the hole at the south pole appears to have diminished quite a bit. There are a couple small equatorial holes within a boiling region where it appears holes are trying to form and connect.
The solar wind speed is 317.1 km/sec, with a density of 8.7 protons/cm3.
SpaceWeather.com says: “The sun has been without sunspots for 33 of the past 34 days. To find a similar stretch of blank suns, you have to go back to 2009 when the sun was experiencing the deepest solar minimum in a century. Solar minimum has returned, bringing extra cosmic rays, long-lasting holes in the sun’s atmosphere, and strangely pink auroras.”
Some nice-sized prominence activity on the Sun over the last couple days; that active region I mentioned above appears as the bright orange area 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.
Asteroids
Upcoming Earth-asteroid encounters:
| Asteroid |
Date(UT)
|
Miss Distance
|
Velocity (km/s)
|
Diameter (m)
|
| 2018 NR1 |
2018-Jul-27
|
17.1 LD
|
5.1
|
35
|
| 2018 OZ |
2018-Aug-06
|
7 LD
|
9.6
|
34
|
| 2018 LQ2 |
2018-Aug-27
|
9.4 LD
|
1.5
|
39
|
| 2016 GK135 |
2018-Aug-28
|
16.8 LD
|
2.8
|
9
|
| 2016 NF23 |
2018-Aug-29
|
13.3 LD
|
9
|
93
|
| 1998 SD9 |
2018-Aug-29
|
4.2 LD
|
10.7
|
51
|
| 2018 DE1 |
2018-Aug-30
|
15.2 LD
|
6.5
|
28
|
| 2001 RQ17 |
2018-Sep-02
|
19.3 LD
|
8.3
|
107
|
| 2015 FP118 |
2018-Sep-03
|
12.3 LD
|
9.8
|
490
|
| 2017 SL16 |
2018-Sep-20
|
8.5 LD
|
6.4
|
25
|
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: 82, this year: 972, all time: 18523.
Potentially hazardous asteroids: 1912 (as of July 31, 2018)
Minor Planets discovered: 779,736 (as of July 31, 2018)
Fireballs
On July 30, 2018, the NASA All Sky Fireball Network reported 21 fireballs.
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point–Earth. Source: Spaceweather.comThe 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 – a few days after Mars opposition – July 31, 2018. Credit: NASA Eyes on the Solar System / Bob Trembley.Exoplanets
Confirmed Exoplanets: 3,774 (7/19/2018)
Multi-Planet Systems: 625 (7/19/2018 )
Kepler Candidate Exoplanets: 4,496 (8/31/2017)
TESS Candidate Exoplanets: 0
Data from the NASA Exoplanet Archive
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.
2018 is NASA’s 60th anniversary!