Marfa Lights

Yes, I’ve seen the Marfa lights. Bernie Zelazny and I were coming back from doing a star party for a culinary group at El Cosmico in Marfa on April 7, 2011 when we decided to stop at the Marfa lights viewing station just off of US 67/90. For the first couple of minutes (Thursday evening around 11:00 p.m. or so) we saw nothing, but then, sure enough, a slowly moving white light appeared near a small tower with red lights, providing a good point of reference for the motion. The light gradually changed brightness, sometimes brighter, sometimes dimmer, moving left to right, then disappeared. Soon, another would appear: sometimes higher, sometimes lower, usually moving to the right, but sometimes to left. My first thought: distant headlights. Sometimes, more that one could be seen at the same time.

Quickly, I ran back to my car to get the 15 x 70 binoculars and binocular mount (an Orion Paragon Plus) and set them up to view the Marfa lights, which by now were happening frequently. When viewing each Marfa light through these powerful binoculars, the first thing I noticed is that I was not able to focus! No matter how I changed the focus of the binoculars, I could do no better than to see a round amorphous blob of light.

Next, I decided to see if any of the fixed distant lights would focus. First the red tower lights. Nope, red blobs. Then a distant ranch light to the left of the light dome of Ojinaga/Presidio. Nope, a while blob. Then, another distant ranch light. Another white blob. Then some distant headlights on US 67/90 near Marfa heading toward Alpine. The headlights were too far away to resolve, and in the binoculars they, too, were an unresolvable white blob. Next I moved the binoculars up a few degrees to look at some stars. Perfect focus! Back down to the ground lights and Marfa lights: out of focus blobs!

So, it appears to me that some atmospheric phenomenon is defocusing and distorting terrestrial lights in the distance. Perhaps some sort of superior mirage. I think the most likely explanation for the Marfa lights is distant vehicle headlights.

Next steps in the investigation of this curious phenomenon: Use a micrometer eyepiece in a low-power rich-field telescope to measure the angular sizes of the Marfa light blobs, as well as the angular sizes of the blobs from identifiable terrestrial lights. Determine the distance to the terrestrial light sources in the daytime (if possible) using triangulation. Better yet, determine the great circle distance to each terrestrial light source by obtaining GPS coordinates of each of those light sources, and the Marfa lights viewing station. Even better would be to shine a mobile light source at the Marfa lights viewing station from various GPS-determined locations at different distances on an evening when the Marfa lights are visible. Determine if the size of each known light blob is a function of distance. Using this information, estimate the distance to the Marfa light sources.

Also, note whether the angular size of each Marfa light is related to its altitude above the horizon.

More ideas: Take a series of 30-second digital camera exposures over the course of an evening to determine if the Marfa lights take preferred paths. The results might support or refute the vehicle headlights hypothesis. Determine if the Marfa lights paths change from night to night or during the course of one night.

Finally, I’d suggest using the same kind of wide-field spectroscopic equipment used to obtain meteor spectra to determine the spectral characteristics of the Marfa lights. This would tell us much about their chemical composition, temperature, and origin.

Forever Stamps

The United States Postal Service has issued a number of enticing forever stamps in recent years, and I’ve begun accumulating stamps faster than I use them. Sound familiar? If so, why not use them for extra postage items—even if you end up spending a little more than is required.

The current value of a forever stamp is 55¢. If you have a postal scale at home to weigh the envelopes you want to post, this handy guide will show you how many forever stamps to use for envelopes of different sizes and weights. (Mail within the U.S. only)

Standard Envelopes (≤11.5″ long, ≤6.125″ high, ≤0.25″ thick)
  • 0 to 1 ounce: 1 forever stamp
  • 1 to 4 ounces: 2 forever stamps
  • 4 to 8 ounces: 3 forever stamps
Large Envelopes (11.5-15″ L, 6.125-12″ H, or 0.25-0.75″ T)
  • 0 to 1 ounce: 2 forever stamps
  • 1 to 4 ounces: 3 forever stamps
  • 4 to 7 ounces: 4 forever stamps
  • 7 to 9 ounces: 5 forever stamps
  • 9 to 12 ounces: 6 forever stamps
  • 12 to 15 ounces: 7 forever stamps

If you are mailing a standard envelope that has one or more of the characteristics in DMM 101.1.2, add an ounce to the measured weight to cover the non-machinable surcharge.

If you are mailing a large envelope that is rigid, is non-rectangular, or is not uniformly thick, then take your envelope to the post office to mail because you will have to pay parcel prices.

Impetus for Iapetus

PIA11690: Global View of Iapetus’ Dichotomy, NASA/JPL/Space Science Institute

What a strange world Iapetus is! The third largest satellite of Saturn—and the outermost of Saturn’s large satellites—is a moon of many mysteries. We’ll take a look at three of them.

Mystery #1: Iapetus appears to be an original satellite of Saturn, and yet unlike the other regular satellites, its orbit is inclined 15.5˚ relative to Saturn’s equator. The reason for this steep inclination is not well understood.

And, oh, the view! Iapetus is the perfect perch to view Saturn’s rings, as it orbits Saturn every 79.3 days in its steeply inclined orbit.

Saturn from Iapetus at the highest point of its inclined orbit

Mystery #2: Iapetus has the largest albedo dichotomy in the solar system. Why? Iapetus is locked in synchronous rotation as it orbits around Saturn, with the leading hemisphere ten times darker than its trailing hemisphere.

Iapetus has an average visual magnitude of 10.2 west of Saturn and 11.9 east of Saturn. Its albedo ranges from 0.5 to 0.05. (Diagram not to scale)
Bright and dark material on Iapetus. The 500-km-wide crater Engelier is at bottom.

It is thought that the natural state of the Iapetian surface is the bright icy part, with the dark material a thin veneer, less than a meter thick.

Mystery #3: Iapetus has a shape consistent with a body spinning every ~16 hours and yet its rotation period is 79.3 days, and it has a prominent ridge that can be followed 3/4 of the way around the equator.

Walnut-shaped Iapetus with its prominent equatorial ridge
Iapetus’ equator-girdling ridge, up to 20 km high, is heavily cratered and therefore ancient

The surface of Iapetus is heavily cratered, indicating it is very old. Could two comparable-sized objects have collided almost head-on billions of years ago to form Iapetus?

Mountainous terrain along Iapetus’ equatorial ridge imaged by the Cassini spacecraft during its closest flyby on September 10, 2007

As beautiful as spacecraft flyby and orbital images are of Iapetus and the many other interesting moons in our solar system, can you imagine what vistas await us once we start exploring their surfaces with rovers? Anticipation of these images and scientific discoveries surely is an impetus to explore the surface of Iapetus (and other moons) sooner rather than later.

Dark and light material on Iapetus was imaged up close by the Cassini spacecraft during its September 10, 2007 flyby.
Sizes of Iapetus, Earth’s moon, and Earth compared


References

Bonnefoy, Léa E., Jean-François Lestrade, Emmanuel Lellouch, Alice Le Gall, Cédric Leyrat, Nicolas Ponthieu, and Bilal Ladjelate. “Probing the subsurface of the two faces of Iapetus.” arXiv preprint arXiv:1911.03394 (2019).

Leleu, Adrien, Martin Jutzi, and Martin Rubin. “The peculiar shapes of Saturn’s small inner moons as evidence of mergers of similar-sized moonlets.” Nature astronomy 2, no. 7 (2018): 555-561.

Rivera-Valentin, Edgard G., Amy C. Barr, EJ Lopez Garcia, Michelle R. Kirchoff, and Paul M. Schenk. “Constraints on planetesimal disk mass from the cratering record and equatorial ridge on Iapetus.” The Astrophysical Journal 792, no. 2 (2014): 127.

Population

Climate change is a serious problem requiring immediate attention. We need to reduce greenhouse gas emissions into our atmosphere as fast as possible. Half measures will not do. We are rapidly running out of time before the quality of life for all humans on planet Earth declines, especially for the economically disadvantaged.

A precipitous decline in biological diversity due to habitat loss and extinction of species is of greater concern, and yet it gets very little attention in the mainstream media. While climate change will render large areas of the Earth uninhabitable, biodiversity loss will lead to a partial or complete collapse of the ecosystem humans depend upon for food.

Getting even less attention is the cause of both of these problems: overpopulation. If you were born in 1973, the world’s human population is now twice what it was then. If you were born in 1952, there are three times as many people alive now than there were then. We have a climate emergency and a biodiversity emergency because we have a population emergency. The number of humans on this planet needs to decline, and the only humane way to accomplish that is to have fewer children. It is that simple.

And, yet, we often see this or that news article lamenting the fact that the birth rate in this or that country is too low. That’s crazy! A low birth rate should be a cause for celebration given the current state of the world and its environment. Certainly, a low birth rate does lead to some economic challenges, but these pale in comparison to the challenges we will face if population (and consumption) continue to grow.

As a humanist, I believe that we should do all we can to alleviate and eliminate human suffering. It is our highest moral calling. To be sure, some human suffering is inevitable and necessary when an individual makes poor decisions and suffers the consequences before hopefully making a mid-course correction. But the kind of suffering I am talking about is suffering that is imposed upon a person through no fault of their own, be it the cruelty of other human beings, or the cruelty of nature.

In this light we can see that our economic systems, governments, and most religions are utterly failing us. Nothing short of drastic changes will solve these problems. May wisdom, intelligence, ingenuity, and compassion guide us, rather than fear, ignorance, hatred, and dogma.

There is an organization dedicated to stabilizing human population throughout the world by lowering the birth rate: Population Connection. I encourage you to support their work as I do.

YearPopulationGrowth Factor
20207,794,798,7391.0
20197,713,468,1001.0
20187,631,091,0401.0
20177,547,858,9251.0
20167,464,022,0491.0
20157,379,797,1391.1
20147,295,290,7651.1
20137,210,581,9761.1
20127,125,828,0591.1
20117,041,194,3011.1
20106,956,823,6031.1
20096,872,767,0931.1
20086,789,088,6861.1
20076,705,946,6101.2
20066,623,517,8331.2
20056,541,907,0271.2
20046,461,159,3891.2
20036,381,185,1141.2
20026,301,773,1881.2
20016,222,626,6061.3
20006,143,493,8231.3
19996,064,239,0551.3
19985,984,793,9421.3
19975,905,045,7881.3
19965,824,891,9511.3
19955,744,212,9791.4
19945,663,150,4271.4
19935,581,597,5461.4
19925,498,919,8091.4
19915,414,289,4441.4
19905,327,231,0611.5
19895,237,441,5581.5
19885,145,426,0081.5
19875,052,522,1471.5
19864,960,567,9121.6
19854,870,921,7401.6
19844,784,011,6211.6
19834,699,569,3041.7
19824,617,386,5421.7
19814,536,996,7621.7
19804,458,003,5141.7
19794,380,506,1001.8
19784,304,533,5011.8
19774,229,506,0601.8
19764,154,666,8641.9
19754,079,480,6061.9
19744,003,794,1721.9
19733,927,780,2382.0
19723,851,650,2452.0
19713,775,759,6172.1
19703,700,437,0462.1
19693,625,680,6272.1
19683,551,599,1272.2
19673,478,769,9622.2
19663,407,922,6302.3
19653,339,583,5972.3
19643,273,978,3382.4
19633,211,001,0092.4
19623,150,420,7952.5
19613,091,843,5072.5
19603,034,949,7482.6
19592,979,576,1852.6
19582,925,686,7052.7
19572,873,306,0902.7
19562,822,443,2822.8
19552,773,019,9362.8
19542,724,846,7412.9
19532,677,608,9602.9
19522,630,861,5623.0
19512,584,034,2613.0
19502,536,431,0183.1

References
World Population Prospects 2019, United Nations.
Worldometers.info; 17 January, 2020; Dover, Delaware, U.S.A.

Satellite and Meteor Crossings 2019 #2

Edmund Weiss (1837-1917) and many astronomers since have called asteroids “vermin of the sky”, but on October 4, 1957 another “species” of sky vermin made its debut: artificial satellites.  In the process of video recording stars for possible asteroid occultations, I frequently see satellites passing through my 17 × 11 arcminute field of view.

I’ve put together a video montage of satellites I serendipitously recorded between August 9, 2019 and December 22, 2019.  Many of the satellite crossings are moving across the fields as “dashes” because of the longer integration times I need to use for some of my asteroid occultation work. A table of these events is shown below the video. The range is the distance between observer and satellite at the time of observation. North is up and east is to the left.

Satellites in higher orbits take longer to cross the field. In the next video, the originally geosynchronous satellite OPS 1570 (IMEWS-3, “Integrated Missile Early Warning System”) is barely visible until it exhibits an amazing sunglint around 3:41:22 UT.

I caught one meteor on October 6, 2019 at 9:57:43 UT. Field location was UCAC4 515-043597. The meteor was a Daytime Sextantid, as determined using the method I described previously in There’s a Meteor in My Image. The meteor even left a brief afterglow—a meteor train!

References
Hughes, D. W. & Marsden, B. G. 2007, J. Astron. Hist. Heritage, 10, 21

Bastien and Bastienne…and Beethoven?

Musical mystery, or compositional coincidence?  Wolfgang Amadeus Mozart wrote the music for his one-act opera Bastien and Bastienne in 1768, at the age of 12.  The short Overture to Bastien and Bastienne bears a remarkable resemblance to the opening theme of Beethoven’s Eroica symphony, composed between 1802 and 1804.  Although the keys are different (Mozart’s overture is in G major and Beethoven’s symphony is in E♭ major), could it be that Beethoven had Mozart’s theme in mind while he composed his 3rd symphony?  It is unlikely that Bastien and Bastienne was known to Beethoven, as that music received its first public performance in 1890.  Perhaps, just a coincidence.  Great minds think alike, it appears.

Overture to Bastien and Bastienne, Statatskapelle Dresden, Sir Colin Davis, RCA 74321-56698-2
Symphony No. 3, “Eroica”, Chicago Symphony Orchestra, Sir Georg Solti, London 430 792-2

An Astronomy Retirement Community

Are any of you nearing retirement (as I am) or already retired who might be interested in moving to an astronomy-oriented retirement community? If you are, I encourage you to join the moderated Groups.io discussion group Dark-Sky Communities at

https://groups.io/g/Dark-Sky-Communities

I am working to establish such a community and would value your input and assistance. That work involves extensive research, networking, writing articles in various publications to reach a wider audience, finding a suitable developer, and seeking benefactors.

Some characteristics of the community I envision include:

  1. Rural location with a dark night sky, but not too far from a city with decent medical facilities, preferably to the northeast or northwest;
  2. Location with an abundance of clear nights and mild winters, probably in Arizona, New Mexico, or West Texas;
  3. Lighting within the community that does not interfere with astronomical activities, strictly enforced;
  4. Community is owned and operated by a benefit corporation or cooperative that will rent a house or apartment to each resident;
  5. Observatories will be available for rental by interested residents who will equip them;
  6. Pro-am collaborative research opportunities will be developed and nurtured;
  7. A community observatory and a public observatory for astronomy outreach will be constructed and maintained;
  8. Lodging will be available for visitors and guests;
  9. There will be opportunities for on-site income operating and maintaining the community or, alternatively, a reduction in monthly rental fees.

Many of us have spent a significant amount of time and energy over the years trying to rein in light pollution in our respective communities and in the wider world, with varying degrees of success. Those efforts should continue, but the grim reality is that light pollution is continuing to get worse almost everywhere.

The opportunity to live in a community of varied interests but with a common appreciation for the night sky and a natural nighttime environment will appeal to many of us. Furthermore, a dark-sky community will afford us opportunities to show the world at large a better way to live.

Traditionally, in the United States at least, if one wants to live under a dark and starry night sky, your only options are to purchase land and build a house on it, or purchase an existing rural home. Not only is buying and maintaining rural real estate unaffordable or impractical for many, many would prefer to live in a rural community, provided that the night sky and nighttime environment are vigorously protected. Rental will also make it easier to move into and out of the community as circumstances change.

Zodiacal Light 2020

In 2020, the best dates and times for observing the zodiacal light are listed in the calendar below. The sky must be very clear with little or no light pollution. The specific times listed are for Dodgeville, Wisconsin (42° 58′ N, 90° 08′ W).

Here’s a nicely-formatted printable PDF file of the zodiacal light calendar:

January 2020
SUN MON TUE WED THU FRI SAT
      1 2 3 4
5 6 7 8 9 10 11
12
Zodiacal Light 6:28 – 7:07 p.m. West
13
Zodiacal Light 6:29 – 7:29 p.m. West
14
Zodiacal Light 6:30 – 7:30 p.m. West
15
Zodiacal Light 6:31 – 7:31 p.m. West
16
Zodiacal Light 6:32 – 7:32 p.m. West
17
Zodiacal Light 6:33 – 7:33 p.m. West
18
Zodiacal Light 6:34 – 7:34 p.m. West
19
Zodiacal Light 6:35 – 7:35 p.m. West
20
Zodiacal Light 6:36 – 7:36 p.m. West
21
Zodiacal Light 6:37 – 7:37 p.m. West
22
Zodiacal Light 6:38 – 7:38 p.m. West
23
Zodiacal Light 6:39 – 7:39 p.m. West
24
Zodiacal Light 6:41 – 7:41 p.m. West
25
Zodiacal Light 6:42 – 7:42 p.m. West
26 27 28 29 30 31  
February 2020
SUN MON TUE WED THU FRI SAT
            1
2 3 4 5 6 7 8
9 10
Zodiacal Light 7:00 – 7:17 p.m. West
11
Zodiacal Light 7:01 – 8:01 p.m. West
12
Zodiacal Light 7:03 – 8:03 p.m. West
13
Zodiacal Light 7:04 – 8:04 p.m. West
14
Zodiacal Light 7:05 – 8:05 p.m. West
15
Zodiacal Light 7:06 – 8:06 p.m. West
16
Zodiacal Light 7:07 – 8:07 p.m. West
17
Zodiacal Light 7:09 – 8:09 p.m. West
18
Zodiacal Light 7:10 – 8:10 p.m. West
19
Zodiacal Light 7:11 – 8:11 p.m. West
20
Zodiacal Light 7:12 – 8:12 p.m. West
21
Zodiacal Light 7:13 – 8:13 p.m. West
22
Zodiacal Light 7:15 – 8:15 p.m. West
23
Zodiacal Light 7:16 – 8:16 p.m. West
24
Zodiacal Light 7:17 – 8:17 p.m. West
25 26 27 28 29

March 2020
SUN MON TUE WED THU FRI SAT
1 2 3 4 5 6 7
8 9 10 11
Zodiacal Light 8:37 – 9:37 p.m. West
12
Zodiacal Light 8:38 – 9:38 p.m. West
13
Zodiacal Light 8:39 – 9:39 p.m. West
14
Zodiacal Light 8:41 – 9:41 p.m. West
15
Zodiacal Light 8:42 – 9:42 p.m. West
16
Zodiacal Light 8:43 – 9:43 p.m. West
17
Zodiacal Light 8:45 – 9:45 p.m. West
18
Zodiacal Light 8:46 – 9:46 p.m. West
19
Zodiacal Light 8:47 – 9:47 p.m. West
20
Zodiacal Light 8:49 – 9:49 p.m. West
21
Zodiacal Light 8:50 – 9:50 p.m. West
22
Zodiacal Light 8:51 – 9:51 p.m. West
23
Zodiacal Light 8:53 – 9:53 p.m. West
24
Zodiacal Light 8:54 – 9:54 p.m. West
25
Zodiacal Light 8:55 – 9:55 p.m. West
26 27 28
29 30 31        

April 2020
SUN MON TUE WED THU FRI SAT
      1 2 3 4
5 6 7 8 9
Zodiacal Light 9:17 – 9:51 p.m. West
10
Zodiacal Light 9:19 – 10:19 p.m. West
11
Zodiacal Light 9:20 – 10:20 p.m. West
12
Zodiacal Light 9:22 – 10:22 p.m. West
13
Zodiacal Light 9:23 – 10:23 p.m. West
14
Zodiacal Light 9:25 – 10:25 p.m. West
15
Zodiacal Light 9:27 – 10:27 p.m. West
16
Zodiacal Light 9:28 – 10:28 p.m. West
17
Zodiacal Light 9:30 – 10:30 p.m. West
18
Zodiacal Light 9:31 – 10:31 p.m. West
19
Zodiacal Light 9:33 – 10:33 p.m. West
20
Zodiacal Light 9:35 – 10:35 p.m. West
21
Zodiacal Light 9:36 – 10:36 p.m. West
22
Zodiacal Light 9:38 – 10:38 p.m. West
23
Zodiacal Light 9:40 – 10:40 p.m. West
24
Zodiacal Light 9:41 – 10:41 p.m. West
25
26 27 28 29 30    
September 2020
SUN MON TUE WED THU FRI SAT
    1 2 3 4 5
6 7 8 9 10 11 12
13 14 15 16
Zodiacal Light 4:05 – 5:05 a.m. East
17
Zodiacal Light 4:06 – 5:06 a.m. East
18
Zodiacal Light 4:07 – 5:07 a.m. East
19
Zodiacal Light 4:09 – 5:09 a.m. East
20
Zodiacal Light 4:10 – 5:10 a.m. East
21
Zodiacal Light 4:11 – 5:11 a.m. East
22
Zodiacal Light 4:13 – 5:13 a.m. East
23
Zodiacal Light 4:14 – 5:14 a.m. East
24
Zodiacal Light 4:15 – 5:15 a.m. East
25
Zodiacal Light 4:16 – 5:16 a.m. East
26
Zodiacal Light 4:17 – 5:17 a.m. East
27
Zodiacal Light 4:19 – 5:19 a.m. East
28
Zodiacal Light 4:20 – 5:20 a.m. East
29
Zodiacal Light 4:27 – 5:21 a.m. East
30      

October 2020
SUN MON TUE WED THU FRI SAT
        1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16
Zodiacal Light 4:41 – 5:41 a.m. East
17
Zodiacal Light 4:42 – 5:42 a.m. East
18
Zodiacal Light 4:43 – 5:43 a.m. East
19
Zodiacal Light 4:44 – 5:44 a.m. East
20
Zodiacal Light 4:46 – 5:46 a.m. East
21
Zodiacal Light 4:47 – 5:47 a.m. East
22
Zodiacal Light 4:48 – 5:48 a.m. East
23
Zodiacal Light 4:49 – 5:49 a.m. East
24
Zodiacal Light 4:50 – 5:50 a.m. East
25
Zodiacal Light 4:51 – 5:51 a.m. East
26
Zodiacal Light 4:52 – 5:52 a.m. East
27
Zodiacal Light 4:53 – 5:53 a.m. East
28
Zodiacal Light 4:55 – 5:55 a.m. East
29
Zodiacal Light 5:24 – 5:56 a.m. East
30 31

November 2020
SUN MON TUE WED THU FRI SAT
1 2 3 4 5 6 7
8 9 10 11 12 13 14
Zodiacal Light 4:13 – 5:13 a.m. East
15
Zodiacal Light 4:15 – 5:15 a.m. East
16
Zodiacal Light 4:16 – 5:16 a.m. East
17
Zodiacal Light 4:17 – 5:17 a.m. East
18
Zodiacal Light 4:18 – 5:18 a.m. East
19
Zodiacal Light 4:19 – 5:19 a.m. East
20
Zodiacal Light 4:20 – 5:20 a.m. East
21
Zodiacal Light 4:21 – 5:21 a.m. East
22
Zodiacal Light 4:22 – 5:22 a.m. East
23
Zodiacal Light 4:23 – 5:23 a.m. East
24
Zodiacal Light 4:24 – 5:24 a.m. East
25
Zodiacal Light 4:25 – 5:25 a.m. East
26
Zodiacal Light 4:26 – 5:26 a.m. East
27
Zodiacal Light 4:27 – 5:27 a.m. East
28
Zodiacal Light 5:17 – 5:28 a.m. East
29 30          

The best nights to observe the zodiacal light at mid-northern latitudes occur when the ecliptic plane intersects the horizon at an angle of 60° or steeper. The dates above were chosen on that basis, with the Sun at least 18° below the horizon and the Moon below the horizon being used to calculate the times. An interval of time of one hour either before morning twilight or after evening twilight was chosen arbitrarily because it is the “best one hour” for observing the zodiacal light. The zodiacal light cone will be brightest and will reach highest above the horizon when the Sun is 18° below the horizon (astronomical twilight), but no less.

If you are interested in calculating the angle the ecliptic makes with your horizon for any date and time, you can use the following formula:

\cos I = \cos \varepsilon \sin \phi-\sin \varepsilon \cos \phi \sin \theta

where I is the angle between the ecliptic and the horizon, ε is  the obliquity of the ecliptic, φ is the latitude of the observer, and θ is the local sidereal time (the right ascension of objects on the observer's meridian at the time of observation).

Here’s a SAS program I wrote to do these calculations:

References
Meeus, J. Astronomical Algorithms. 2nd ed., Willmann-Bell, 1998, p. 99.

Meteor Shower Calendar 2020

Here’s our meteor shower calendar for 2020.  It is sourced from the IMO’s Working List of Visual Meteor Showers (https://www.imo.net/files/meteor-shower/cal2020.pdf, Table 5, p. 25).

Each meteor shower is identified using its three-character IAU meteor shower code.  Codes are bold on the date of maximum, and one day either side of maximum.

Here’s a printable PDF file of the meteor shower calendar shown below:

Happy meteor watching!

January 2020
SUN MON TUE WED THU FRI SAT
      1
DLM QUA
2
DLM QUA
3
DLM QUA
4
DLM QUA
5
DLM QUA
6
DLM QUA
7
DLM QUA
8
DLM QUA
9
DLM QUA
10
DLM QUA GUM
11
DLM QUA GUM
12
DLM QUA GUM
13
DLM GUM
14
DLM GUM
15
DLM GUM
16
DLM GUM
17
DLM GUM
18
DLM GUM
19
DLM GUM
20
DLM GUM
21
DLM GUM
22
DLM GUM
23
DLM
24
DLM
25
DLM
26
DLM
27
DLM
28
DLM
29
DLM
30
DLM
31
DLM ACE
 
February 2020
SUN MON TUE WED THU FRI SAT
            1
DLM ACE
2
DLM ACE
3
DLM ACE
4
DLM ACE
5
ACE
6
ACE
7
ACE
8
ACE
9
ACE
10
ACE
11
ACE
12
ACE
13
ACE
14
ACE
15
ACE
16
ACE
17
ACE
18
ACE
19
ACE
20
ACE
21 22
23 24 25
GNO
26
GNO
27
GNO
28
GNO
 
March 2020
SUN MON TUE WED THU FRI SAT
1
GNO
2
GNO
3
GNO
4
GNO
5
GNO
6
GNO
7
GNO
8
GNO
9
GNO
10
GNO
11
GNO
12
GNO
13
GNO
14
GNO
15
GNO
16
GNO
17
GNO
18
GNO
19
GNO
20
GNO
21
GNO
22
GNO
23
GNO
24
GNO
25
GNO
26
GNO
27
GNO
28
GNO
29 30 31        
April 2020
SUN MON TUE WED THU FRI SAT
      1 2 3 4
5 6 7 8 9 10 11
12 13 14
LYR
15
PPU LYR
16
PPU LYR
17
PPU LYR
18
PPU LYR
19
ETA PPU LYR
20
ETA PPU LYR
21
ETA PPU LYR
22
ETA PPU LYR
23
ETA PPU LYR
24
ETA PPU LYR
25
ETA PPU LYR
26
ETA PPU LYR
27
ETA PPU LYR
28
ETA PPU LYR
29
ETA LYR
30
ETA LYR
   
May 2020
SUN MON TUE WED THU FRI SAT
          1
ETA
2
ETA
3
ELY ETA
4
ELY ETA
5
ELY ETA
6
ELY ETA
7
ELY ETA
8
ELY ETA
9
ELY ETA
10
ELY ETA
11
ELY ETA
12
ELY ETA
13
ELY ETA
14
ARI ELY ETA
15
ARI ETA
16
ARI ETA
17
ARI ETA
18
ARI ETA
19
ARI ETA
20
ARI ETA
21
ARI ETA
22
ARI ETA
23
ARI ETA
24
ARI ETA
25
ARI ETA
26
ARI ETA
27
ARI ETA
28
ARI ETA
29
ARI
30
ARI
31
ARI
           
June 2020
SUN MON TUE WED THU FRI SAT
  1
ARI
2
ARI
3
ARI
4
ARI
5
ARI
6
ARI
7
ARI
8
ARI
9
ARI
10
ARI
11
ARI
12
ARI
13
ARI
14
ARI
15
ARI
16
ARI
17
ARI
18
ARI
19
ARI
20
ARI
21
ARI
22
JBO ARI
23
JBO ARI
24
JBO ARI
25
JBO
26
JBO
27
JBO
28
JBO
29
JBO
30
JBO
       
July 2020
SUN MON TUE WED THU FRI SAT
      1
JBO
2
JBO
3
CAP
4
CAP
5
CAP
6
CAP
7
CAP
8
CAP
9
CAP
10
CAP
11
CAP
12
CAP SDA
13
CAP SDA
14
CAP SDA
15
CAP SDA PAU
16
CAP SDA PAU
17
PER CAP SDA PAU
18
PER CAP SDA PAU
19
PER CAP SDA PAU
20
PER CAP SDA PAU
21
PER CAP SDA PAU
22
PER CAP SDA PAU
23
PER CAP SDA PAU
24
PER CAP SDA PAU
25
PER CAP SDA PAU
26
PER CAP SDA PAU
27
PER CAP SDA PAU
28
PER CAP SDA PAU
29
PER CAP SDA PAU
30
PER CAP SDA PAU
31
PER CAP SDA PAU
 
August 2020
SUN MON TUE WED THU FRI SAT
            1
PER CAP SDA PAU
2
PER CAP SDA PAU
3
KCG PER CAP SDA PAU
4
KCG PER CAP SDA PAU
5
KCG PER CAP SDA PAU
6
KCG PER CAP SDA PAU
7
KCG PER CAP SDA PAU
8
KCG PER CAP SDA PAU
9
KCG PER CAP SDA PAU
10
KCG PER CAP SDA PAU
11
KCG PER CAP SDA
12
KCG PER CAP SDA
13
KCG PER CAP SDA
14
KCG PER CAP SDA
15
KCG PER CAP SDA
16
KCG PER SDA
17
KCG PER SDA
18
KCG PER SDA
19
KCG PER SDA
20
KCG PER SDA
21
KCG PER SDA
22
KCG PER SDA
23
KCG PER SDA
24
KCG PER
25
KCG
26 27 28
AUR
29
AUR
30
AUR
31
AUR
         
September 2020
SUN MON TUE WED THU FRI SAT
    1
AUR
2
AUR
3
AUR
4
AUR
5
SPE AUR
6
SPE
7
SPE
8
SPE
9
DSX SPE
10
STA DSX SPE
11
STA DSX SPE
12
STA DSX SPE
13
STA DSX SPE
14
STA DSX SPE
15
STA DSX SPE
16
STA DSX SPE
17
STA DSX SPE
18
STA DSX SPE
19
STA DSX SPE
20
STA DSX SPE
21
STA DSX SPE
22
STA DSX
23
STA DSX
24
STA DSX
25
STA DSX
26
STA DSX
27
STA DSX
28
STA DSX
29
STA DSX
30
STA DSX
     
October 2020
SUN MON TUE WED THU FRI SAT
        1
STA DSX
2
ORI STA DSX
3
ORI STA DSX
4
ORI STA OCT DSX
5
ORI STA OCT DSX
6
ORI STA DRA OCT DSX
7
ORI STA DRA DSX
8
ORI STA DRA DSX
9
ORI STA DRA DSX
10
ORI DAU STA DRA
11
ORI DAU STA
12
ORI DAU STA
13
ORI DAU STA
14
ORI EGE DAU STA
15
ORI EGE DAU STA
16
ORI EGE DAU STA
17
ORI EGE DAU STA
18
ORI EGE DAU STA
19
LMI ORI EGE STA
20
NTA LMI ORI EGE STA
21
NTA LMI ORI EGE STA
22
NTA LMI ORI EGE STA
23
NTA LMI ORI EGE STA
24
NTA LMI ORI EGE STA
25
NTA LMI ORI EGE STA
26
NTA LMI ORI EGE STA
27
NTA LMI ORI EGE STA
28
NTA ORI STA
29
NTA ORI STA
30
NTA ORI STA
31
NTA ORI ST
November 2020
SUN MON TUE WED THU FRI SAT
1
NTA ORI STA
2
NTA ORI STA
3
NTA ORI STA
4
NTA ORI STA
5
NTA ORI STA
6
LEO NTA ORI STA
7
LEO NTA ORI STA
8
LEO NTA STA
9
LEO NTA STA
10
LEO NTA STA
11
LEO NTA STA
12
LEO NTA STA
13
NOO LEO NTA STA
14
NOO LEO NTA STA
15
NOO AMO LEO NTA STA
16
NOO AMO LEO NTA STA
17
NOO AMO LEO NTA STA
18
NOO AMO LEO NTA STA
19
NOO AMO LEO NTA STA
20
NOO AMO LEO NTA STA
21
NOO AMO LEO NTA
22
NOO AMO LEO NTA
23
NOO AMO LEO NTA
24
NOO AMO LEO NTA
25
NOO AMO LEO NTA
26
NOO LEO NTA
27
NOO LEO NTA
28
PHO NOO LEO NTA
29
PHO NOO LEO NTA
30
PHO NOO LEO NTA
         
December 2020
SUN MON TUE WED THU FRI SAT
    1
PUP PHO NOO NTA
2
PUP PHO NOO NTA
3
HYD PUP PHO NOO NTA
4
GEM HYD PUP PHO NOO NTA
5
DLM GEM HYD MON PUP PHO NOO NTA
6
DLM GEM HYD MON PUP PHO NOO NTA
7
DLM GEM HYD MON PUP PHO NTA
8
DLM GEM HYD MON PUP PHO NTA
9
DLM GEM HYD MON PUP PHO NTA
10
DLM GEM HYD MON PUP NTA
11
DLM GEM HYD MON PUP
12
DLM COM GEM HYD MON PUP
13
DLM COM GEM HYD MON PUP
14
DLM COM GEM HYD MON PUP
15
DLM COM GEM HYD MON PUP
16
DLM COM GEM HYD MON
17
DLM URS COM GEM HYD MON
18
DLM URS COM GEM HYD MON
19
DLM URS COM GEM HYD MON
20
DLM URS COM GEM HYD MON
21
DLM URS COM
22
DLM URS COM
23
DLM URS COM
24
DLM URS
25
DLM URS
26
DLM URS
27
DLM
28
DLM QUA
29
DLM QUA
30
DLM QUA
31
DLM QUA
   

Venus: Future Earth?

In terms of bulk properties, Venus is the most Earthlike planet in the solar system. The diameter of Venus is 95% of Earth’s diameter. The mass of Venus is 82% of Earth’s mass. It has a nearly identical composition.

But…the average surface temperature of Venus is 735 K (863˚ F) and the surface atmospheric pressure is 91 times greater than Earth’s—equivalent to the pressure 3,000 ft. below the ocean’s surface. The present atmosphere of Venus is composed of 96.5% carbon dioxide (CO2) and 3.5% nitrogen (N2), plus a number of trace elements and compounds.

Venus was not always so inhospitable. What happened?

The cratering record suggests that nearly all of Venus has been resurfaced within the last 300 – 800 Myr. Before that, Venus probably was much more hospitable, even habitable, perhaps. The Pioneer Venus large probe and infrared spectral observations from Earth of H2O and HDO (deuterated isotope of water) indicate that the deuterium-to-hydrogen ratio in the Venusian atmosphere is 120 – 157 times higher than in water on Earth, strongly suggesting that Venus was once much wetter than it is today and that it has lost much of the water it once had to space. (Hydrogen is lighter than deuterium and therefore more easily escapes to space.) In addition to deuterium abundance, measuring the isotopic abundance ratios of the noble gases krypton and xenon would help us better understand the water history of Venus. These cannot be measured remotely and requires at-Venus sampling.

Venus receives 1.92 times as much solar radiation as the Earth, and this was undoubtedly a catalyst for the runaway greenhouse effect that transformed the Venusian climate millions of years ago.

We know that CO2 is a potent greenhouse gas, but anything that increases the amount of water vapor (H2O) in the atmosphere leads to global warming as well. As do clouds.

Climate modeling shows us that that the hothouse on the surface of Venus today is due to CO2 (66.6%), the continual cloud cover (22.5%), and what little water vapor remains in the atmosphere (10.9%).

Interestingly, if all the CO2 and N2 in the Earth’s crust were somehow liberated into the atmosphere, our planet would have an atmosphere very similar to Venus.

Venus is the easiest planet to get to from Earth, requiring the least amount of rocket fuel. There is so much we still don’t understand about how Venus transformed into a hellish world, and we would be well-advised to learn more about Venus because it may inform us about Earth’s future as well.

Tessera terrain covers about 7% of the surface of Venus. These highly deformed landforms, perhaps unique in the solar system, may allow us to someday sample the only materials that existed prior to the great resurfacing event.

COLORIZED TOPOGRAPHIC DATA OVERLAID UPON FORTUNA TESSERA TERRAIN IMAGE
In this radar image, blue represents the lowest elevations, white the intermediate elevations, and red the highest elevations. Source: Emily Lakdawalla, https://www.planetary.org/blogs/emily-lakdawalla/2013/02071317-venus-tessera.html .

If living organisms ever developed on Venus, the only place they could still survive today is 30 miles or so above the surface where the atmospheric temperature and pressure are similar to the surface of the Earth.

Even four billion years ago, Venus may have been too close to the Sun for life to develop, but if it did, Venus probably remained habitable up to at least 715 Myr ago.

Now for the bad news. All main-sequence stars, including our Sun, slowly brighten as they age, and their habitable zones move outward from their original locations. Our brightening Sun will eventually render the Earth uninhabitable, certainly within the next two billion years, and our water could be lost to the atmosphere and then space within the next 13o million years, leading to a thermal runaway event and an environment similar to that of Venus. Human-induced climate change could make the Earth uninhabitable for humans and many other species long before that.

One indication that water is being lost to space and surface warming is occurring is water vapor in the stratosphere. The more water vapor that is in the stratosphere, the more water is being forever lost to space and the greater the surface warming. Careful and continuous monitoring of water vapor levels in the Earth’s stratosphere is important to our understanding of climate change on Earth.

To conclude, Arney and Kane write:

“Venus teaches us that habitability is not a static state that planets remain in throughout their entire lives. Habitability can be lost, and the runaway greenhouse is the final resting place of once watery worlds.”

References

Arney, G., & Kane, S. 2018, arXiv e-prints, arXiv: 1804.05889

Bézard, B., & de Bergh, C. 2007, J. Geophys. Res., 112, E04S07, doi: 10.1029/2006JE002794.

Ostberg, C., & Kane, S. R. 2019, arXiv e-prints,arXiv: 1909.07456

Way, M.J. 2019, EPSC Abstracts, 13, EPSC-DPS2019-1846-1

Way, M. J., Del Genio, A. D., Kiang, N. Y., et al. 2016, Geophys. Res. Lett., 43, 8376