The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence.
If the sky is clear, you will find Jupiter Venus the Western sky just after sunset (1). If you manage that, have a look near overhead at Mars (2), the Moon (3) over to the East and for Extra Points, the (4) Constellation Orion. Please see revised chart for March 4, ’23, at 6:30 PM,below
The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence.
The comet is now well-within visible range – but it will take considerable snakey-eyed concentration to pick it out. More importantly, there will be clear skies on Friday night. I put together this chart with instructions. Print it out and follow instructions. If you need light to see the chart, close one eye while you turn on the flashlight. Or, use an eye-patch to keep night vision in one eye while consulting chart. Professional Astronomers do this, while making corny pirate jokes. 😉
The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence.
So, at this point, I know my audience.
See Venus and Jupiter in Close Conjunction, Saturday, April 30 – around 6 AM
Venus is the “skymark” for a collection of planets in the morning sky.
Look East before dawn to find Jupiter, Venus, Mars and Saturn lined up in the Southeast. Jupiter is the lowest in the sky and second-brightest. A bit higher is Venus – the brightest by far with Mars next and then Saturn. See the sky chart below for reference. If you print it out, the best way to use it is to hold it with “East” at the bottom and face East.
Figure 1: Skychart for April 19th from Heavens-Above.com
Don’t imagine that these planets are actually anywhere near each other. The diagram below should give the reader the “Big Picture”. The positions of the planets (including the one you are standing on). Figure
Figure 2: Yellow lines depict the “lines of sight” from an observer on Earth to the four planets. To give scale: The line from you to Saturn is almost a billion miles long.
The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence.
So, at this point, I know my audience.
Comet 2021 A1 – Leonard
There is another “Eyes Only Visible” comet to be seen in the Southwestern sky, just after sunset. The current magnitude of Leonard is +4.6, so in the city, it is only just visible and would be better seen with binoculars. Once again, do not use telescopes or binoculars to view the Sun – blindness will result! I said “after sunset” so you should be OK if you listen to me. 😉
As is usual in these cases, the comet gets brighter not only because it gets close to the Earth. It also gets brighter because it gets closer to the Sun. The third brightening influence is the material that the closer sun vaporizes. That stuff makes a cloud around the comet and is it also partially blown away by what is called the Solar Wind – in a comet’s tail.
Figure 1, above shows the location to view, which is conveniently close to Venus, which is the brightest thing in the sky. If you can see the Planet, you should be able to see the comet – although you may need those binoculars to do so.
We have had very cloudy weather here in Houston (today, Dec 19) is “Mostly Cloudy” at 4 PM, changing to “Cloudy” around Sunset at 5:26 PM. Tommorow at Sundown the prediction is “Mostly Cloudy” and the comet will have moved slightly relative to Venus. These next few days are literally the last chance to see Leonard, as it is on a hyperbolic orbit – which is a nerdy way to say that it will never return to the Solar System. (Please see figure 2 below)
Figure 2. Comet Leonard is diving through the Solar System, never to return.
For readers not in the Houston area, just look for Venus (and Jupiter for orientation) and use the chart above to find the comet. We are lucky to be able to have the two brightest objects in the sky (now that the moon is not around in the early evening) as our reference points.
Once again, we – on Earth – will be passed by a Near-Earth Asteroid. This time on April 12th. Don’t worry! Its nearest approach will be about 38 thousand kilometers (23,800 miles). For reference, the diameter of the Earth is about 8000 miles. The size of this is a rock that you could hide a Ford Expedition behind.
Near Earth Asteroid…Date……….Miss Distance…..Velocity (km/s)…..Diameter (meters)……
Figure 1: Parameters of Near-Earth encounter with 2021GW4
Figure 2: Orbits of Earth, the Moon and 2021GW4. These are calculated without the Earth’s gravity effect on the asteroid’s orbit. The red line suggests what might happen in reality.
The question on everyone’s lips is always what will happen IF this asteroid were to collide with the Earth. It will not do that, OK?
People just love to imagine catastrophe and asteroids are their greatest opportunity. So, I have developed a macro to calculate such a disaster given the mass of the asteroid and the relative velocity of that asteroid with the Earth. Now, there are many variables (also referred to as “parameters”) that effect such calculations and I have made many assumptions – based on “average” values of density – and so forth. So, if you calculate a different number, please let me know – and show your work!
With all those disclaimers, I will say that the asteroid’s impact – if its course were to coincide with the position of the Earth (which WILL NOT HAPPEN, by the way!) – would generate an explosion equivalent to 1.3 kilotons of TNT. This is calculated by the Kinetic Energy using the estimated mass of the NEA and the velocity from the table in figure 1.
For reference, the bombing of Hiroshima yielded an explosion estimated at 12 to 18 kilotons. For an extreme example the “Tsar Bomba” detonated by the Soviet Union in 1961 yielded about 50 Megatons (50,000 Kilotons). So, we have already done far more damage on our own than this particular object could heap upon us.
The Earth has gone around the Sun again and Jupiter is in the morning sky once more. The Urban Astronomy Cursor (AKA, The Moon) is again indicating that planet around 6 to 7 AM. Shortly thereafter the Sun rises. Readers will remember that the “last time around” Jupiter and Saturn were close neighbors. Now more distant, they are. You will find Saturn at a 45 degree angle up and to the right from Jupiter.
The waning crescent Moon points out Jupiter and Saturn.
As a lifelong Astronomy Nerd (perhaps not at birth, but not long after) I cannot help but notice how Planetary Science has advanced over the last half century. To say that much has been discovered is a ridiculous understatement. This theme of Solar System Astronomy can also be noticed in my other Categories (Comets, Planets, Asteroids, Urban Astronomy, Science and occasionally even in Going Walkabout, Energy, One Climate Fact and Humor*.
*These are the collections behind those icons on my homepage atGoingwalkabout.blog.
This is a summary of what I knew about this fly-by of 2014 MU69, going into the Lunar and Planetary Conference (LPSC) of 2019. I subsequently wrote a “post conference” summary and many editions and deletions later, the foreshortened, simplified result appeared in Ad Astra Magazine: STILL SEEKING NEW HORIZONS: Ad Astra – Summer 2019 page 48.
A great deal of the detail that I included in this preliminary draft was left out of the final product. The length, format and tone were, of course, the choice of the editor. Since this early pre-conference composition contains but little of the final result, I take the liberty of presenting it in my own publication (again Goingwalkabout.blog.)
I will also be adding original commentary and explanation, so I reckon that it is original material by any definition. My intention is to also present (later) the post-conference story – partly in original form – which contained quite a bit of detailed and interesting information that did not fit Ad Astra’s “tone and format”. Not to criticize Ad Astra, you understand, but only to display my own interest and enthusiasm for richer detail. And, I want to present some of that in my own publication, free to read (and – alas – to write for) though it may be.
Before the Lunar and Planetary Science Conference in 2019
New Horizon Fly-by of Kuiper Belt Object (486958) 2014 MU69 (a.k.a., Ultima Thule)
By Steve Campbell
February 2019
After a successful fly-by of Pluto in July 2015 (to read more, please see Sneaking Up on Pluto, Part Iand Part 2), the New Horizons space probe followed up with another encounter on New Year’s Day 2019. This target was a much smaller body known as 2014 MU69 and frequently referred to by its nickname “Ultima Thule” (and subsequently “officially” called 486958 Arrokoth – as of late 2019)
The first opportunity for publication and presentation of those results will be the Lunar and Planetary Science Conference and will take place between March 12th and March 18th, 2019. The limited data transmission capability from New Horizons had the result that less than 1% of encounter data had been received when the LPSC abstracts for presentations were due. As one abstract’s introduction states,
“Therefore, many new, quite substantial results not available at the time of this abstract submission will be presented in the actual review talk.” (4)
Pluto and MU69 are both Kuiper Belt Objects. I will now explain what that means.
The Kuiper Belt
As of the 1930’s, the Solar system had been thought of as divided into the realm of the planets and the distant Oort Cloud. Dutch astronomer Jan Oort deduced this spherical “halo” of objects by studying the movements and behavior of long-period comets. A third zone between those two was later postulated to explain the many “short-period” comets that tend to be near the planetary plane and have periods of 200 years or less. Since the discovery of Pluto it had been suspected that a torus of such small bodies existed. It was named for Gerard Kuiper (1905 – 1973) who was a Dutch-born American astronomer and planetary scientist of great distinction. In an appropriate coincidence, Jan Oort was one of Kuiper’s teachers in Holland in the early years of the 20th Century.
Subsequent discoveries of Kuiper Belt objects (now in the thousands) have led to a more detailed division of zones within and near the belt. KBOs are distinct from comets only because they are so far from the sun that they do not produce the comas or tails.
Centaurs: These are KBOs orbiting in the zone of the outer planets, thought to have been scattered there from the Kuiper Belt by the gravitational influence of (primarily) Neptune. From there they may be further thrown sunward by the other giant planets.
Resonant: This applies to a KBO whose orbit crosses that of Neptune. These will not be thrown sunward further since their orbital periods are such that they always find themselves far from Neptune. Pluto is the prototype Resonant KBO and has an orbit that takes it around the sun twice for every three orbits of Neptune.
Cold Classical KBOs: These are KBOs that stay in the zone outside Neptune’s influence and thus avoid being re-directed by that planet. The “Cold” qualifier refers to the fact that these orbits are not inclined to the orbits of the planets and are near-circular.
Hot Classical: Similar to the “Cold” bunch, but these KBO’s have elongated orbits that tend to be substantially inclined.
Scattered: As you might expect from the name, none of the restrictions applied to the other categories apply to this bunch. These are the population that wind up as Centaurs or short-period comets.
New Horizons Probe
The idea of a Pluto exploration was not as a “flagship” mission like the Voyagers (Grand Tour) or the Cassini Saturn orbiter. Its goal was to target a fly-by of Pluto directly, but also to carry on into the Kuiper Belt and visit other, as yet undiscovered bodies. The budget was a shoestring compared to many previous missions and while the instruments were advanced and powerful, many compromises were made to balance the launch and timing of the mission, the way data were collected and transmitted and the cost and reliability of hardware. The vast distance to Pluto was compounded by the fact that the multiple gravity-assists enjoyed by the Voyager probes, were not possible. Only Jupiter was reasonably positioned for the “slingshot effect” — and that only for a limited time.
The result was a small spacecraft, launched away from Earth by the most powerful rocket available, adorned with extra strap-on boosters and outfitted with a third stage to achieve a record-fast trajectory.
The probe pointed its instruments by rotating the whole spacecraft – meaning that all data collection was done while the antenna that would transmit to Earth was pointed off at deep space. The images and data for the entire fly-by of Pluto and later 2014 MU69 had to be recorded and “played back” later when instrument-pointing was no longer in operation and contact with Earth could be restored. Payload considerations limited the size of the high-gain antenna, and hence, the data transmission rate. As with Pluto before, the entirety of the MU69 fly-by data will not be on Earth until well over a year after the fly-by (August/September of 2020). Besides the slow data rate, there was an additional delay because the probe had slipped behind the Sun, as viewed from Earth, in January.
Figure 1: The New Horizons Probe. Credit: NASA
The instruments are described here as quoted from the New Horizons web site (1):
“The New Horizons team selected instruments that not only would directly measure NASA’s items of interest, but also provide backup to other instruments on the spacecraft should one fail during the mission. The science payload includes seven instruments:
Ralph: Visible and infrared imager/spectrometer; provides color, composition and thermal maps.
Alice: Ultraviolet imaging spectrometer; analyzes composition and structure of Pluto’s atmosphere and looks for atmospheres around Charon and Kuiper Belt Objects (KBOs).
LORRI: (Long Range Reconnaissance Imager) telescopic camera; obtains encounter data at long distances, maps Pluto’s farside and provides high resolution geologic data. SWAP: (Solar Wind Around Pluto) Solar wind and plasma spectrometer; measures atmospheric “escape rate” and observes Pluto’s interaction with solar wind.
PEPSSI: (Pluto Energetic Particle Spectrometer Science Investigation) Energetic particle spectrometer; measures the composition and density of plasma (ions) escaping from Pluto’s atmosphere.
SDC: (Student Dust Counter) Built and operated by students; measures the space dust peppering New Horizons during its voyage across the solar system.”
The alert reader will note that the same antenna (REX) that returns data to the Earth is also listed as an instrument. It was used to measure the changes in an Earth-NH transmission as the signal was eclipsed by Pluto’s atmosphere and surface and the same situation was also measured at Charon.
The data capacity of the probe is only 8 Gigabytes. While that is not impressive in today’s realm of technology, it must be remembered that New Horizons was launched in 2006. And, as is typical in spacecraft design, the technology designated for use in the probe was “frozen” some years before that.
To put that in perspective, available memory for the Voyager probes (Launched in 1977) was actually on a ½ inch, 8 track magnetic tape with a total capacity of about ½ Megabyte and a top baud rate of 56kilobits per second (2). Since the technology was frozen five years before launch, it was some, 17 years out-of-date by the time Voyager 2 flew past Neptune in 1989.
2014 MU69 (AKA Ultima Thule)
The New Horizons space probe was a resounding success as it flew by Pluto. The long-patient team of planetary scientists were then eager to find new targets. After all, the probe was still in good shape, with enough fuel to change its direction somewhat and find more distant targets in the Kuiper Belt. There was, however, no known object in a suitable position to arrange that.
Extensive observations by ground-based telescopes found more KBOs but none within reach of the probe. So, a Hubble Space Telescope survey was commissioned by the New Horizons team and found three valid candidates – of which 2014 MU69 was targeted. (5)
Before the encounter this KBO was examined by telescope observations and distant examination by the spacecraft itself, whose battery of instruments includes a telescope (LORRI), which while not nearly as powerful as the major observatories on Earth, it had the advantage of being very much closer.
There was also a campaign of occultation observations to characterize the shape of the body and assist in targeting by precisely measuring the orbit. This is a time-tested method to characterize the shape and refine measurement of an asteroid by precisely timing the disappearance of a star that is expected to pass behind the target. The “shadow” of such a small body – itself, so very far away – is about the same size as the KBO to be measured. It is nonetheless miniscule and fleeting on the face of the Earth and is best measured by teams of observers, spaced appropriately – in this case about 4 kilometers (2.5 miles apart). They must travel to the expected path of said shadow, bring their own portable equipment and deal with weather, geography and bureaucracy. Four such occultations were observed with varying success and were, taken together, sufficient to pin down the rate of movement of MU69 and to indicate that the KBO was either a pair of close-orbiting bodies or an elongated shape, possibly a “contact binary”. For results, please see figure 2, below.
Figure 2: Results of occultation observations indicated a close binary, elongated shape or a contact binary nature of the KBO. The latter proved to be true. Credit NASA
So, rather ironically, to pin down the parameters needed to make the fly-by a success required the efforts of observers – all the way back on the Earth – mostly armed with 16-inch telescopes and other equipment that (the author estimates) could be purchased for the price of a late-model used car.
Characterization
The orbit of MU69 around the Sun is so nearly circular that the difference is less than 5 percent. This would seem to indicate that this is a primordial object, formed where it is found now and not a displaced asteroid that might have been ejected from the inner solar system, for example.
Because it is a Classical KBO, the two bodies making up the object are thought to be formed where they currently are and gently captured into a binary system where they eventually merged to form a “contact binary”. Even at this early stage the KBO is being referred to as “pristine”.
In other words, this is not something that was formed elsewhere and then cast out by gravitational interactions the outer planets. Nor was it altered much since its formation.
The spectral analysis revealed that the composition is similar to Pluto. That “dwarf planet” has been altered a great deal by differentiation as a planetary body, by an acquired atmosphere and by interaction with it large satellite, Charon.
Distant, low resolution images sent to Earth by the probe — just before the encounter – pictured the target planetoid as a close binary. The initial images (at better, but still lower resolution) pictured MU69 as a “contact binary”. That is, two planetoids so close in orbit around a common center that they are in physical contact. Please see Figure 3.
Figure 3: MU69 Credit: Nasa
The KBO is much darker than all the images herein indicate. Those pictures are “stretched” to show the difference in brightness. The true colors range from dark red to really dark red. The red color is contributed by nitrogen-rich organic compounds called tholins, which are described by the following quote from NASA
“…in the late 1970s, scientists made an organic substance in the laboratory that matched the reddest asteroids. The substance’s color spectrum ranged from yellow to red to black, and was termed “tholin” by Carl Sagan in 1980. Scientists measured and modeled the optical properties of tholins, and found that the tholins matched the observed red color of the majority of the most distant asteroids.”
The New Horizons probe has been determined to be approaching from almost a “pole-on” direction. This will limit the imaging of the other side which is mostly unilluminated at this point in the KBO’s orbit around the sun.
A great deal more data, images and analyses were presented at the Lunar and Planetary Science Conference in Houston on March 18 – 22, 2019.
The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence. So, at this point, I know my audience.
By the way on the date of this post, you should go out shortly before sunset and look for the Jupiter/Saturn Conjunction in the Southwest sky. Don’t look at the Sun, OK?
By the way, on the date of this post, go out shortly before sunset and look for theJupiter/Saturn Conjunction.
So far, I have used the moon as a cursor to point out the planets Venus, Mars, Jupiter and Saturn. This is four of the five “eyes only” planets and since Mercury is so elusive, we have pretty much run out of subjects. There is other stuff in the sky, of course and we might just as well look at those.
As stated in my prolog for this series, the night sky is a mystery to city dwellers and they might find stars interesting. Why – you may ask – would I be interested in points of white light that never change? Long ago, people were interested in stars because they clearly documented the progress of the seasons. If you are a subsistence farmer (and most people were) you had a vested interest in knowing when to plant and when to harvest your crops.
As these farmers – and later astronomers – studied the stars, they came to know that they are not all the same color and they actually do change – at least some do. Furthermore, a few of the stars are not actually single points of light, but are surrounded by luminous gas and dust. Some look like single stars but – under closer observation – are actually double or triple stars. Some are clusters of stars with likewise interesting traits.
So, this time I’ll send you out to look at the moon and then direct your attention at the constellation of Orion. The date is December 28, 2020 and time is 2100 (nine PM). This is Houston and US Central Standard Time, but around this date, if you can find the moon, after sunset, you should be able to find the constellation. Orion is known for its three bright stars in “Orion’s Belt”, as well as its two brightest stars, Betelgeuse* and Rigel. You will see them labeled on the skymap, below.
*You may wonder how to pronounce this. As a young elementary school student, I did too. Nobody around the elementary school knew either and I called it, “bet” (wager) “tel” (as in telephone) “geeze” (as in geezer). With accent on the wager.
Nobody had the knowledge to say otherwise until a college Astronomy professor corrected me. The word sounds just like “Beetle Juice”.
Steve: Sorry, I didn’t know!
Prof: It’s OK Mr. Campbell, nobody does at first.”
Obviously, I was not the first ten-year old Astronomy Nerd.
As you see, I have marked Orion with an arrow from the moon to Orion (that I have apparently drawn with a blue crayon). Also, please note the “A” that I have placed to point out an object to be discussed later.
I will also post a time-lapse photo I made of this region of the sky. It shows about half of Orion. I could show you the whole constellation, but this picture was photobombed by a passing helicopter. You can see that the aircraft had a constant white light and a flashing red one. I could probably take pictures every night for a year and not capture something like this – that happened by accident alone.
This 10 or 20 second exposure was taken in early 2020. Of the three stars in Orion’s Belt, you see two, below the big yellow “2”. I have pictures with all three, but no helicopter. The big yellow “1” annotates Betelgeuse, the red-hued star that is the brightest of all in the constellation and referred to as “Alpha Orionis” – meaning the brightest star in Orion. The big yellow “3” shows you Rigel, the second brightest star in Orion (Beta Orionis).
“Hold on there, Laddybuck!” you are saying, “I can clearly see that Rigel (Yellow Three) is much brighter than Betelgeuse.”
At that particular time, it was, indeed. Betelgeuse is a variable star and pulsates – not as extremely as that red helicopter beacon, but at least enough to make you all say, “Hold on there, Laddybuck!”
And, in fact this particular dimming of Alpha Orionis was unprecedented. Please see chart below:
Betelgeuse Brightness 1965 – 2020
As you can see, Betelgeuse’s drop in brightness was the most severe in many decades. There was actual serious speculation that Betelgeuse was collapsing. When red supergiant stars (of which Betelgeuse is one) collapse, the result is a catastrophic explosion called a Supernova. Is Betelgeuse headed that way? If so, the “Conventional Wisdom” is that – because the star really, really big and is so close to our Solar System, a Betelgeuse Supernova might easily be visible in the daytime…perhaps for months.
I looked up some more recent data and found the answer…Maybe – but not immediately.
Betelgeuse Brightness 9/2018 – 5/2020
You see that the brightness has recovered completely.
However, who is to say that this unprecedented drop will not be repeated? It may take some extreme oscillations to trigger the Supernova.
The night sky is pretty much a mystery to most City Dwellers. The glare of city light drowns out all but the brightest stars – and planets don’t do much better. If you are interested, I can tell you where to look to see these far-off worlds. If you were not interested, you would have stopped reading after the first sentence. So, at this point, I know my audience.
Prelude
Astronomers have known – for centuries – a secret that reveals the true nature of God! Doubt me if you must, but listen to what I have to say and see if you do not agree.
These astronomers, from centuries ago until now, have all either learned by experience or have been told of an odd thing called “averted vision”.
Explanation
This situation comes about because vision is ruled by the light detecting nerves in your eye. There are two types, “rods” (low-light sensitive and color insensitive) and “cones” (color sensitive and high resolution but 40 times less sensitive to light in general)
The center of your field-of-view is just lousy with cones and that’s how you read small fonts and so forth. Your peripheral vision (“in the corner of your eye”) is loaded with rods that detect light quite well, but are not particularly descriptive about it. It is described in more detail at Sky at Night Magazine
So, over the centuries astronomers learned to look away slightly in order to see more of what they wanted to see. Sounds a bit silly, does it not?
“…When I was a child I caught a fleeting glimpse Out of the corner of my eye I turned to look but it was gone…”
You will notice that this short quote pretty much describes what I have been talking about. The rest of the lyrics have been interpreted by others quite differently as you will see at that link above.
Discussion
So, what of this claim about the true nature of God? This is the first clue I had that God is the biggest (of course) Practical Joker in the Universe.
Imagine this conversation:
God: Do you want to see that better?
Mortal: Well…yes, I do.
God: Don’t look at it!
Mortal: Say What?!
God: You heard me!
(a pause)
Mortal: Hey, wow!
God: Told ya! (chuckle)
Some will tell you that this is just “Evolution”. Others might say that it is God’s Will.
And at least one man asked, what’s the difference?* It was Pope John Paul II – who had no problem with “Evolution”.
*About Life in general, not just averted vision
Epilog
Somehow a small planet created beings capable of asking how they came to be there. It is the only such place we know of. This even though we have actively looked for extra-terrestrial life and/or intelligence – with steadily increasing range, accuracy and sensitivity – for about a Century.
Say, perhaps all of Life is God’s Practical Joke on the Universe! 😉
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