Comet 21P Flys By

What a very nice image of Comet 21 P//Giacobini-Zinner by Greg Ruppel (this image via ESA). Very nice indeed, it’s not as easy to do as one might think. Heh, I came to that conclusion about 2 seconds after I tried it. Fun though.

I wanted to mention we could have a naked-eye comet on the way. The comet is 46P/Wirtanen and could be down around a magnitude 3 in December and with decent skies it should be visible. Note that comets are not necessarily like stars in terms of brightness as comets are more diffuse. More on 46P/Wirtanen later.

As for comet 21P ESA included a great companion story: Something small and green recently flittered across our skies. On 10 September, comet 21P/Giacobini-Zinner made its closest approach to the Sun in 72 years — 151 million km from our star and just 58.6 million km away from Earth (about a third of the distance from here to the Sun).Discovered in 1900, this small comet reappears every 6.6 years. At just two km in diameter, 21P’s cometary tail contains a stream of ‘cometary crumbs’, and as Earth moves through this stream of debris it creates the Draconid meteor shower which peaks every year around 8 October.

Comets are leftovers of the formation of the Solar System, and while they are typically less dense than asteroids they pass Earth at relatively higher speeds, meaning the impact energy of a comet’s nucleus is slightly larger than that of a similar-sized asteroid.

Although no comet is conclusively known to have impacted Earth, there are many proponents of the theory that a fragment of Comet Encke — a periodic comet that orbits the Sun every 3.3 years — resulted in one of the most well-known impact events in our planet’s history.

In 1930, the British astronomer F.J.W. Whipple suggested that the Tunguska event of 1908 — in which an explosion over Eastern Siberia Taiga flattened 2000 square km of forest — was in fact the result of a cometary impact.

No impact crater was ever found, and glowing skies were reported across Europe for several evenings after the event, both supporting the notion that a comet, composed of dust and volatiles — such as water ice and frozen gases — could have been completely vaporised as it smashed into Earth’s atmosphere leaving no obvious trace.

In order to better understand the risk that asteroids and comets pose to our planet, we need to better understand their orbit and composition. Missions such as Rosetta — the first spacecraft to orbit a comet’s nucleus — play a vital role in deepening our understanding of the objects in our Solar System that could pose some risk. ESA’s planned Hera mission to a binary asteroid to test asteroid deflection will be an important step in doing something about them.


This stunning image was taken on 9 September 2018 by Greg Ruppel, at his robotic observatory in Animas, New Mexico. For more of Greg’s images of Comet 21P/Giacobini-Zinner, and more, visit his website.

History in the Making

Who will be the first passenger to go to the moon and back (hopefully)? SpaceX has signed a passenger and that person will be the first to ride the SpaceX BFR Mission to the Moon. The trip has been made by just 24 people in history.

We are about to find out who, when, and why! History in the making.

When? The SpaceX website says 18 Sept 2018 at 01:00 UT / 21:00 ET (on 17 Sept). However if one actually does the math using the little “timer to live” they give on the link, the start times are an hour BEFORE that.  It can be confusing, that’s why I will almost always use UTC and the prevailing US Eastern time, I figure people in the states and Canada will easily convert that to what ever timezone they are in.

I am going to err on the side of caution and publish an hour before hand (the 1 am time). The 21:00 ET / 01:00 UT time makes more sense because that is 18:00 PDT.

India Launches Two British Satellites

Coverage from India of the ISRO launch of two British Satellites, the NovaSAR-1 and SSTL S1-4 satellites into a 583 km Sun Synchronous Orbit from the First Launch Pad (FLP) of Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota

I think India has shown it’s ability to provide commercial launch capabilities — excellent work.

By the way, speaking of commercial / private space services, one of the world’s leaders Space X is about to make a major announcement.

I Like a Good Mystery Now and Then

Image: NSO

UPDATE 2:  News reports say the Observatory is re-opening this week and the shut down was due to “criminal activity”. That’s about all we know for certain at the moment. I’d wager that unless what ever “criminal activity” means it better be big and made public because the conspiracy theory side of things is running amok as things stand now and ANYTHING less than “significant” will just feed that narrative.

There is a mystery in the United States astronomical community.

What is going on here? Hmmmm?

This from the Association of Universities for Research in Astronomy:

AURA Addressing Security Issue at NSO Facility

September 14, 2018

The Association of Universities for Research in Astronomy (AURA) is addressing a security issue at the National Solar Observatory (NSO) facility at Sacramento Peak, New Mexico and has decided to temporarily vacate the facility as a precautionary measure until further notice. All other NSO facilities are open and operating normally. AURA, which manages Sacramento Peak with funding from the National Science Foundation, is working with the proper authorities on this issue.


As with any “hush-hush” sort of thing rumors are sure to get going and really big things move the rumor-mill into full fledged conspiracy theories. Conspiracy theories? Of course we have conspiracy theories, a bit of inappropriate language taints what could have been a great article it’s still pretty good, have a look.

There are a multitude of stories on this, I like the Daily Mail account.

Here is the FB page.

Sooner or later we’ll find out what happened, until then enjoy the mystery.

ICESat-2 Launching Today

NASA is launching a mission called ICESat=2 today. The ICESat-2 spacecraft has a single instrument, the Advanced Topographic Laser Altimeter System (ATLAS), which will send 10,000 laser pulses a second to Earth’s surface and measure the height of ice sheets, glaciers, sea ice and vegetation. The time for the laser to return will determine the height, pretty straight forward even if technically challenging.

The launch will be from Vandenberg California so no tropical systems to get in the way.

Coverage starts at 12:10 UTC / 08:10 EDT / 05:46 PDT with the launch window opening up at 12:46 UTC / 08:46 EDT / 05:46 PDT.

Coverage is via NASA, the link below will go to NASA TV programming so will be active before hand.

Here is a replay from “VideoFromSpace”. I was a bit tardy about this, spent too much time looking around for information on the Solar Observatory closure – and I found nothing much.

Florence from the ISS

Florence is not as strong as it could have been, the problem with this is everybody thinks in terms of wind speed and sure 160 kmh (100 mph) is much-much better than 225 kmh (140 mph). No doubt about it but the BIG problem, apathy aside, is the water and the very slow motion of this storm, days of rain, flooding rains for days!

Apathy? Well yes, that happens when earlier reports were for those 225 kmh winds and then they are “only” 160, people could let down their guard — it’s very common.

People, please be careful around creeks and rivers and road washes. Seriously this is a very acute danger, BE CAREFUL! DO NOT DRIVE THROUGH FLOODING ROADS!

Ok, I’m off my soapbox.

The View from Vera Rubin Ridge

This is great! Click play and move around using the circle thing with the arrows on the upper left as the video.

Original caption: After snagging a new rock sample on August 9, 2018 (Sol 2137), NASA’s Curiosity rover surveyed its surroundings on Mars, producing a 360-degree panorama of its current location on Vera Rubin Ridge. The scene is presented with a color adjustment that approximates white balancing, to resemble how the rocks and sand would appear under daytime lighting conditions on Earth. Two versions are included here: one with scale bars, and one without.

The panorama includes umber skies, darkened by a fading global dust storm. It also includes a rare view by the Mast Camera of the rover itself, revealing a thin layer of dust on Curiosity’s deck. In the foreground is the rover’s most recent drill target, named “Stoer” after a town in Scotland near where important discoveries about early life on Earth were made in lakebed sediments.

More information about Curiosity is online at and

Florence – Big Trouble

International Space Station Astronaut Ricky Arnold shared this image of Hurricane Florence a couple of days ago (Sept. 10).  Credit: NASA

If you are in the in the warned areas of this very dangerous storm please be safe. I remember a storm named Hugo some years ago and Florence could be about as devastating – let’s hope not.

I have heard rain potential in some areas to exceed 45 cm plus the winds apparently could hinder drainage in the coastal areas.  That’s before, during and after dealing with winds around 225 kmh / 140 mph.

Some areas could feel the start of the storm later tonight and certainly by tomorrow morning.

Saturn at Opposition from Hubble

A beautiful image of Saturn and some of its moons from the Hubble Space Telescope.

Credit: NASA, ESA, A. Simon (GSFC) and the OPAL Team, and J. DePasquale (STScI); CC BY 4.0

Original caption: \Cassini ended its 13-year mission at Saturn on 15 September 2017 when it plunged into the gas giant’s atmosphere, but the NASA/ESA Hubble Space Telescope is still keeping an eye on the ringed planet.

This is a composite image taken by Hubble on 6 June 2018 showing a fully-illuminated Saturn and its rings, along with six of its 62 known moons. The visible moons are (from left to right) Dione, Enceladus, Tethys, Janus, Epimetheus and Mimas (click here for an annotated version). Dione is the largest moon in the picture, with a diameter of 1123 km, compared to the smallest, oddly-shaped Epimetheus with a diameter around 116 km.

During Cassini’s mission, Enceladus was identified as one of the most intriguing moons, with the discovery of water vapour jets spewing from the surface implying the existence of a subsurface ocean. Icy moons with subsurface oceans could potentially offer the conditions to harbour life, and understanding their origins and properties are essential for furthering our knowledge of the Solar System. ESA’s JUpiter ICy moons Explorer (Juice), due to launch in 2022, aims to continue this theme by studying Jupiter’s ocean-bearing moons: Ganymede, Europa, and Callisto.

The Hubble image shown here was taken shortly before Saturn’s opposition on 27 June, when the Sun, Earth and Saturn were aligned so that the Sun fully illuminated Saturn as seen from Earth. Saturn’s closest approach to Earth occurs around the same time as opposition, which makes it appear brighter and larger and allows the planet to be imaged in greater detail.

In this image the planet’s rings are seen near their maximum tilt towards Earth. Towards the end of Cassini’s mission, the spacecraft made multiple dives through the gap between Saturn and its rings, gathering spectacular data in this previously unchartered territory.

The image also shows a hexagonal atmospheric feature around the north pole, with the remnants of a storm, seen as a string of bright clouds. The hexagon-shaped cloud phenomenon is a stable and persistent feature first seen by the Voyager 1 space probe when it flew past Saturn 1981. In a study published just last week, scientists using Cassini data collected between 2013 and 2017, as the planet approached northern summer, identified a hexagonal vortex above the cloud structure, showing there is still much to learn about the dynamics of Saturn’s atmosphere.

The Hubble observations making up this image were performed as part of the Outer Planet Atmospheres Legacy (OPAL) project, which uses Hubble to observe the outer planets to understand the dynamics and evolution of their complex atmospheres. This was the first time that Saturn was imaged as part of OPAL. This image was first published on 26 July.