In the Sky this Week – June 1, 2021

I recently learned about the Square Kilometre Array – an international effort to build “the world’s largest radio telescope.” Sites are being built in both Africa and Australia – the total collecting area of the SKA will be well over one square kilometer!

Cover Image: Composite image of the SKA-Mid telescope in South Africa. The image blends a real photo (on the right) of the existing MeerKAT radio telescope dishes, with an artist’s impression of the future SKA-Mid dishes as they will look when constructed (left). The 15m wide dish telescopes, will provide the SKA with some of its highest resolution imaging capability, working towards the upper range of radio frequencies which the SKA will cover. Credit: SKAO, SARAO

I am completely gobsmacked by the data processing requirements of the SKA Project:

… scientists and engineers are working on a system which will require two supercomputers each 25% more powerful than the best supercomputer in the world in 2019, and network technology that will see data flow at a rate 100,000 times faster than the projected global average broadband speed in 2022.

…there is a desire to reach hundreds of Gigabits per second. This will require network infrastructure will surpass the global internet by a huge factor in terms of the amounts of data being sent globally. Signal processing has never witnessed anything on this scale.

Image: Nighttime composite image of the SKA combining all elements in South Africa and Australia. This image blends photos of real hardware already on the ground at both sites with artist’s impressions of the future SKA antennas. From left: artist’s impression of the future SKA dishes blend into the existing precursor MeerKAT telescope dishes in South Africa. From right: artist’s impression of the future SKA-Low stations blends into the existing AAVS2.0 prototype station in Western Australia. Credit: SKAO, ICRAR, SARAO Acknowledgment: The GLEAM view of the centre of the Milky Way, in radio colour.

For the last several decades, the field of astronomy has been generating an enormous and an accelerating amount of data – I have to wonder how this compares with other fields of science like biology and chemistry?

Jupiter and Saturn continue to appear in the southeastern predawn sky all week – the Moon appears near Jupiter on June 1st.

The constellation Ursa Major, and the “Big Dipper” asterism appears nearly overhead after sunset – this is an excellent opportunity to try star-hopping; follow a curve from of the handle of the “Big Dipper,” and you will come to the star Arcturus. If you continue the curve, you will come to the star Spica. The “Big Dipper” can be used to star-hop to multiple different stars and constellations.

Mars and Venus appear above the western horizon after sunset, Mars appears near-ish to the star Pollux in the constellation Gemini. Mercury, which was VERY close to Venus in the sky last week is now well below the horizon.

The star Pollux is classified as a K0 III giant, quite a bit larger than our Sun; it is also the closest giant star to the Sun.

The Moon appears in the southern morning sky after sunrise from June 1-6th, although it may be a bit difficult to see after June 4th.

A very thin waning crescent Moon appears in the eastern predawn sky on June 7th – look for earthshine! You can point to the Moon and tell your friends and family the the planet Uranus is slightly above the Moon, and the dwarf planet Ceres is to the right and closer to the horizon.

The Moon is a Waning Gibbous – rising after sunset, visible high in the sky after midnight, and visible to the southwest after sunrise.

The Third Quarter Moon occurs on June 2nd – rising around midnight, and visible to the south after sunrise

After June 2nd, the Moon will be a Waning Crescent – visible low to the east before sunrise.

If you click on the Moon image above, or click this link, you will go to NASA’s Moon Phase and Libration, 2021 page – it will show you what the Moon looks like right now. If you click the image on that page, you will download a high-rez TIFF image annotated with the names of prominent features – helpful for logging your lunar observations!

Moon News:

The Sun seems to like having 2 Earth-facing spots – it’s been that way for weeks, and it’s that way again! AR2827 harbors energy for M-class flares. Image (left): The Sun on June 1, 2021. Credit: SDO/HMI

Spaceweather.com reports: “AN OFF-TARGET CME MIGHT SIDESWIPE EARTH TODAY: Minor G1-class geomagnetic storms are possible on June 1st when a CME is expected to sideswipe Earth’s magnetic field. The storm cloud was hurled into space on May 28th by departing sunspot AR2824. High-latitude sky watchers should be alert for auroras, especially in the southern hemisphere where autumn darkness favors visibility.”

Intense coronal loop activity with flares around sunspot 2827, smaller but active loops over 2828. The northern coronal hole remains wide open, and there are several patchy coronal holes on the Sun’s face.

Prominences everywhere, again! Sunspot 2824 looks very angry at this frequency – you can see it blowing flares!

Solar Activity on Facebook – Run by Volunteer NASA/JPL Solar System Ambassador Pamela Shivak

Solar Corona

Solar wind speed is 303.3 km/sec, with a density of 6.0 protons/cm³ at 1155 UT.

Click here to see a near real-time animation of the corona and solar wind from the Solar & Heliospheric Observatory (SOHO).

Sun News:

• Near-Earth Objects (NEOs) discovered this month: 227, this year: 1100 (+8), all time: 25,888 (+13)
• Potentially hazardous asteroids: 2180 (+1) (updated 2021-05-25)
• Total Minor Planets discovered (NASA): 1,083,459 (+2457)
• Total Minor Planets discovered (MPC): 1,069,907 (updated 2021-04-27)

Upcoming Earth-asteroid encounters:

Asteroid News:

WARNING WILL ROBINSON! “A potentially hazardous asteroid is zooming past Earth on Tuesday!”

Whenever I see a headline like this, I head over to the JPL Small Body Database Browser to have a look at the asteroid’s orbit.

Uh huh… just as I thought! The article states that Potentially Hazardous Object 2021 KT1 will pass within 4,600,000 miles – that’s 19.2 Lunar Distances. Many of the objects in the Asteroid Close Encounter table above frequently pass much closer than that, but hey THIS asteroid has that “Potentially Hazardous Asteroid” label attached to it, so it’s more exciting!

I worry more about asteroids that pass within 1 lunar distance – especially the ones passing within the geosynchronous satellite ring! Asteroid 2021 KT1 was discovered on April 23, 2021, and is passing by the Earth just a couple months afterwards – a trend that has been, and will be growing over time.

I just noticed the NAME of this thing… KT1… Yikes!!! K-T referring to the infamous asteroid strike 65 million years ago.

On May 31, 2021, the NASA All Sky Fireball Network reported 11 fireballs!
(11 sporadics)

Fireball News:

If you see a bright meteor or a fireball, please REPORT IT to the American Meteor Society and the International Meteor Organization!

Position of the planets & several spacecraft in the inner solar system on June 1st:

Position of the planets in the middle solar system:

Position of the planets, and a several spacecraft in the outer solar system:

Solar System News:

International Space Station:

HiRISE – on the Mars Reconnaissance Orbiter:

Hubble Space Telescope:

Landsat:

NASA Orion – New Zealand Joins Artemis Accords

Climate

See a list of current NASA missions here: https://www.jpl.nasa.gov/missions/?type=current

ex·o·plan·et /ˈeksōˌplanət/, noun: a planet orbiting a star other than the Sun.

Data from the NASA Exoplanet Archive
* Confirmed Planets Discovered by TESS refers to the number planets that have been published in the refereed astronomical literature.
* TESS Project Candidates refers to the total number of transit-like events that appear to be astrophysical in origin, including false positives as identified by the TESS Project.
* TESS Project Candidates Yet To Be Confirmed refers to the number of TESS Project Candidates that have not yet been dispositioned as a Confirmed Planet or False Positive.

Exoplanet Resources

My wife is teaching her astronomy students about exoplanets this week – I sent her this list of websites:

• NASA Exoplanet Archive: https://exoplanetarchive.ipac.caltech.edu/
• NASA Eyes on Exoplanets: https://eyes.nasa.gov/apps/exo/#/
• NASA Exoplanet Travel Bureau: https://exoplanets.nasa.gov/alien-worlds/exoplanet-travel-bureau/
• NASA Space Tourism Posters: https://solarsystem.nasa.gov/resources/682/space-tourism-posters/

SpaceWeather.com Realtime Aurora Gallery: https://spaceweathergallery.com/aurora_gallery.html

This was reported in a “Michigan Dark Sky” email!

I’ve been to the Keweenaw Mountain Lodge, and it would be a fantastic place to host a star party!! And I happen to know a lot of people in the Keweenaw Peninsula!

Visit an International Dark Sky Park: https://www.darksky.org/our-work/conservation/idsp/parks/

If you live in Michigan, visit the Michigan Dark Skies site: https://sites.lsa.umich.edu/darkskies/

NASA Space Place – For Teachers:

“Sharks with *******’ laser beams attached to their heads!”

I cannot help but think of this EVERY TIME I’ve heard the word LASER… for decades…

Beautiful Universe: Cassini Mission – Density Waves in Saturn’s Rings

When the Cassini mission arrived at Saturn, I was frantic with excitement – just ask my wife! I remember seeing this image from Cassini and feeling utter astonishment!

This view from NASA’s Cassini spacecraft shows a wave structure in Saturn’s rings known as the Janus 2:1 spiral density wave. Resulting from the same process that creates spiral galaxies, spiral density waves in Saturn’s rings are much more tightly wound. In this case, every second wave crest is actually the same spiral arm which has encircled the entire planet multiple times.

This is the only major density wave visible in Saturn’s B ring. Most of the B ring is characterized by structures that dominate the areas where density waves might otherwise occur, but this innermost portion of the B ring is different.

The radius from Saturn at which the wave originates (toward lower-right in this image) is 59,796 miles (96,233 kilometers) from the planet. At this location, ring particles orbit Saturn twice for every time the moon Janus orbits once, creating an orbital resonance. The wave propagates outward from the resonance (and away from Saturn), toward upper-left in this view. For reasons researchers do not entirely understand, damping of waves by larger ring structures is very weak at this location, so this wave is seen ringing for hundreds of bright wave crests, unlike density waves in Saturn’s A ring. 

The image gives the illusion that the ring plane is tilted away from the camera toward upper-left, but this is not the case. Because of the mechanics of how this kind of wave propagates, the wavelength decreases with distance from the resonance. Thus, the upper-left of the image is just as close to the camera as the lower-right, while the wavelength of the density wave is simply shorter. 

This wave is remarkable because Janus, the moon that generates it, is in a strange orbital configuration. Janus and Epimetheus (see PIA12602) share practically the same orbit and trade places every four years. Every time one of those orbit swaps takes place, the ring at this location responds, spawning a new crest in the wave. The distance between any pair of crests corresponds to four years’ worth of the wave propagating downstream from the resonance, which means the wave seen here encodes many decades’ worth of the orbital history of Janus and Epimetheus. According to this interpretation, the part of the wave at the very upper-left of this image corresponds to the positions of Janus and Epimetheus around the time of the Voyager flybys in 1980 and 1981, which is the time at which Janus and Epimetheus were first proven to be two distinct objects (they were first observed in 1966). 

Epimetheus also generates waves at this location, but they are swamped by the waves from Janus, since Janus is the larger of the two moons. 

This image was taken on June 4, 2017, with the Cassini spacecraft narrow-angle camera. The image was acquired on the sunlit side of the rings from a distance of 47,000 miles (76,000 kilometers) away from the area pictured. The image scale is 1,730 feet (530 meters) per pixel. The phase angle, or sun-ring-spacecraft angle, is 90 degrees.

–NASA

Annnnnnnnnd this is the first time I’ve actually read about what they are, and now I’m even MORE amazed! MAN I love this stuff!

Stay safe, be well, and look up!

Software Apps used for this post:

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.
SpaceEngine: a free 3D Universe Simulator for Windows. Steam version with VR support available.
Stellarium: a free open source planetarium app for PC/MAC/Linux. It’s a great tool for planning observing sessions. A web-based version of Stellarium is also available.

Section header image credits:
The Sky – Stellarium / Bob Trembley
Observing Target – Turn Left at Orion / M. Skirvin
The Moon – NASA/JPL-Caltech
The Sun – NASA/JPL-Caltech
Asteroids – NASA/JPL-Caltech
Fireballs – Credited to YouTube
Comets – Comet P/Halley, March 8, 1986, W. Liller
The Solar System – NASA Eyes on the Solar System / Bob Trembley
Spacecraft News – NASA Eyes on the Solar System / Bob Trembley
Exoplanets – Space Engine / Bob Trembley
Light Pollution – NASA’s Black Marble
Aurora – Bob Trembley
The Universe – Universe Today