Category: space

Sky Sights November 2019

Greetings skywatchers! November is a busy month this year with two meteor showers, a transit of Mercury, and a conjunction. First, a few words about Daylight Saving Time. Unless you live in Hawaii, Puerto Rico or Arizona (except the Navajo Nation), you are aware that we turned our clocks back to Standard Time this past Sunday. Since the passage of the Uniform Time Act in 1966, most of us have lived our whole lives “springing forward” and “falling back” each year. It’s interesting to note that this biannual time change now occurs mostly without our participation.

Our smartphones, laptops, smart TVs, and smart appliances adjust themselves without any help from us. We may have to set the clock in the car, or the microwave oven clock, but even these will eventually take control of their temporal condition, leaving us to spend the day debating whether Daylight Saving Time saves energy or increases demand (or both, or neither?). Then the next morning we wake up too early or too late, feeling a little grumpy, and promptly forget about the entire matter. What started over a century ago as a way for people to make better use of daylight is now implemented and observed primarily by the clocks themselves.

This month we have an exciting daytime viewing opportunity: during the day on Veterans Day (Nov. 11th) most of the Americas will have an excellent view of the transit of Mercury. A transit occurs when we observe a smaller celestial body moving across the face of a larger one. In this case, we will be able to see little Mercury skating across the Sun over six hours, starting at 7:34 am EST/6:34 am CST.

Credit: NASA

This is an event you can safely observe at a public observatory or sky-watching party where telescopes fitted with a special filter can be safely used for observation. Some are listed below but check with your local astronomy club for the one nearest to you. Please don’t attempt to watch the transit with your naked eyes, sunglasses, or binoculars. This can cause very serious damage to your eyes. This includes special eclipse glasses. While technically you could look at the Sun with such glasses if they are well-made, you would be unable to pick out Mercury due to the difference in size: keep in mind that Mercury, as it appears from Earth, is just 1/194th the size of the Sun!

For younger skywatchers, here’s a helpful video for kids that explains the basics of the transit:

In addition to the transit, we have two meteor showers this month; first, the Taurids are known for their fireball meteors, and the first few weeks of November are the best time to look for them. The Full Moon on the 12th (13:34 UTC/8:34 am EST/7:34 am CST/6:34 am MST/5:34 am PST), also known as the Frost Moon or Beaver Moon (since beavers typically build their winter dams around this time) will give them some competition for a few nights.

A few days after the Full Moon, you can look out for the Leonids, which will peak between the 16th and the 18th. The Moon will be waning gibbous and so this year’s Leonid shower will not be especially prominent, but you may be able to catch sight of a few of them.

On Sunday the 24th, there is a conjunction of Venus and Jupiter arriving just in time for Thanksgiving. Look for the pair about an hour after sunset in the southwestern sky. They will appear very low in the sky so you’ll need a good view of the horizon. Then on Thanksgiving Day, the crescent Moon meets up with Venus and the next night with Saturn! It’s a great opportunity to use binoculars for a closer look and impress family and friends with your knowledge of the night sky. Of course, I never do this…

Good luck and see you next month!

Alex

[Note: the top image depicts the conjunction of Venus and Jupiter just after sunset on Nov. 24th. I created this image using Stellarium, an open-source planetarium program that is available at http://stellarium.org]

Here are some DC-area events planned for the transit of Mercury on Nov. 11:

Analemma Society viewing event at Turner Farm, Great Falls

Astronomical Society of Greenbelt viewing party, Greenbelt

Howard Astronomical League viewing party at Alpha Ridge Park, Marriottsville

George Mason University public viewing event at GMU Observatory, Fairfax

National Air & Space Museum Observatory viewing event, Washington DC

If the weather is nice there will likely be a viewing party somewhere near you! Use this site to find one:

NASA Night Sky Network

If inclement weather prevents outdoor viewing, you can still watch the transit online:

Slooh Internet Observatory viewing event

Virtual Telescope Project online viewing event

NASA Solar Dynamics Observatory (images made during transit)

The Speech that Led Us to the Moon

As we approach July 20th and the 50th anniversary of the Apollo 11 landing on the Moon, the focus will naturally be on the astronauts and their journey. Yet we should also recall that the lunar landing may not have happened save for a brief speech on a warm September day a long time ago.

It might be surprising to Americans today, accustomed to media sound bites, “fake news,” and general unfamiliarity with the art of oratory, that a speech can persuade minds and even turn the course of history. It has the power to reshape attitudes and behaviors. A great speech, like a great book or film, makes you ponder and reflect long after you have absorbed it.

Most of the great orations of the past exist today as transcriptions, sometimes quite inaccurate in their recording. The actual words of Pericles and Mark Antony are lost to history; we hope that medieval copyists give us their essence if not their original flavor. Even in the modern era, a speech that comes to us in print may not be the one that was actually delivered. The oft-cited example of the Gettysburg Address demonstrates how the text can be misremembered or misrecorded and in most cases cannot capture the diction, cadence, and manner of the speaker.

The first voice recording we have of a president is a fragment of Benjamin Harrison speaking about the first Pan-American Congress in 1889;1 it is barely enough, but sufficient to suggest what the elocution of a late 19th-century orator sounded like. A few other early recordings of 19th-century public figures such as William Jennings Bryan and P.T. Barnum impress upon a listener how public speech in the Victorian era compares to the efforts of our contemporary practitioners, those loquacious beneficiaries of content-optional high-definition video and surround sound.

Yet it was a gradual descent into our current mediagenic morass where anyone with something to say can act the amateur journalist, policy maven, or podcaster. Although TV and video technology advanced rapidly in the 1950s, it took a while for public figures to become aware (and consequently self-aware) that they could adopt the affectations of film stars and dictators to enthrall the home audience and still give a coherent speech. Thus the film and TV appearances of public figures in the late 1950s and early 1960s have a verisimilitude that is seldom found in our century; they preserve a momentary balance of form and content before the medium engulfed the message.

My exemplar here is President Kennedy’s speech at Rice University on September 12, 1962. This is the now-famous “Moon” speech that JFK delivered before an audience of 40,000 gathered in Rice Stadium.2 The rhetorical power of his remarks still resonates today and can be compared favorably with speeches by any of his successors. For those of us too young to recall Kennedy or the Apollo missions, it’s remarkable that, through technology, we can still appreciate this 18-minute speech and the achievements that followed from it.


Notes:

1 Thomas Edison wrote in his diary that he demonstrated the first version of his recording phonograph for Rutherford Hayes at the White House in April 1878. Unfortunately, no surviving recording of the president’s voice has ever been discovered.
2 This is the original video as partially restored by NASA, and you will see about halfway through the video, the quality improves dramatically. The figure just behind the president (wearing sunglasses) is Vice President Johnson, the chair of the National Aeronautics and Space Council and the primary force behind Project Apollo. Also, note that the Venus space probe referred to by the president is Mariner 2, which in December 1962 became the first spacecraft to reach another planet.

Photo credit: Robert Knudsen. White House Photographs. John F. Kennedy Presidential Library and Museum, Boston

Leonids this Weekend!

This is just a reminder that the Leonid meteor shower peaks this weekend. If your local skies are clear, your best viewing opportunities will be tonight and Saturday night. Try to go out after midnight and just look up, you don’t have to search one area of the sky, and the absence of the Moon will increase your chances.

If the skies are uncooperative, you may enjoy this story about Abraham Lincoln’s experience observing the famous Leonid shower of 1833.

http://www.skyandtelescope.com/wp-content/uploads/LincolnandLeonids.pdf

Good luck and Happy Thanksgiving!

Sky Sights November 2017

The image above depicts Venus and Jupiter in the eastern sky at dawn on Nov. 11. They will reach conjunction early on the morning of Nov. 13. I created this image using Stellarium which is available at http://www.stellarium.org/

Greeting skywatchers! We have some exciting events coming up this month, starting with the Hunter’s Moon this weekend. The Full Moon arrived at 1:23 am this morning so tonight and Sunday night will provide excellent opportunities to do some lunar observing if you have clear skies and a telescope or mounted binoculars. The Hunter’s Moon is the Full Moon after the Harvest Moon (which is the Moon closest to the autumnal equinox, as you may recall from last month).

The term Hunter’s Moon has been around since the early 1700s and usually refers to the appreciation of hunters that denuded trees and harvested fields make spotting animals easier. Also, because the Full Moon this month is pretty close the Moon’s perigee (its closest approach to Earth, a little less than two days later), some are calling this Hunter’s Moon a “supermoon”; however I will disagree, although it should be nice and bright!

On the morning of Nov. 13, look for the conjunction of Venus and Jupiter (the two brightest planets) in the low eastern sky just before dawn. Venus will be present in the dawn sky for the whole month but is gradually sinking toward the horizon, while Jupiter will be rising higher every day, and this conjunction at a separation of just 0.3° will be exceptional. Meanwhile, Saturn continues to loiter near the horizon in the evenings and will be visible low in the southwest sky after sunset.

This month’s featured meteor shower is the Leonid shower, which will peak on Nov. 17-18. This corresponds nicely with the New Moon on Nov. 18 so the darker skies will favor meteor hunting. The Leonids are debris from Comet Tempel-Tuttle and normally produce 10-15 meteors per hour on average. The radiant for the Leonids is close to the star Algieba (Gamma Leonis) in the mane of Leo, but the general rule is that you can look anywhere in the sky for meteors!

Finally, on a more terrestrial note, Daylight Saving Time ends tonight and most of the US returns to Standard Time at 2 am Sunday morning. Here in 2017, computers, smartphones/smart appliances, and digital TVs will (or should) automatically adjust their internal clocks, so you will only need to set your unconnected clocks and watches back one hour. This typically means car clocks, older appliances, and old clocks and timers from the 20th century or earlier (I would poke fun at these antique unconnected devices, but my opinion is that Daylight Saving Time is silly anyway!).

Farewell, Cassini

Greetings skywatchers! By the time you read this, the Cassini spacecraft will have likely disintegrated in the atmosphere of Saturn, ending an amazing mission that began 20 years ago with its 1997 launch from Cape Canaveral. As we look back over the history of Cassini, here are some of my favorite resources for you to enjoy and learn from. Don’t forget that you can go out this month and see Saturn in the south-southwest after sunset.

NASA Cassini mission page
Cassini basic fact sheet
Cassini by the numbers
Why is Cassini important?
Cassini dives between Saturn and its rings
Cassini top 10 discoveries (2014)
Cassini orbiter spacecraft details
Huygens lander spacecraft details
Focus on Titan
Focus on Enceladus
Focus on Rhea

40th Anniversary of Voyager 1

Today is the 40th anniversary of the launch of Voyager 1, the beginning of its journey to Jupiter and Saturn. Voyager 2 was launched two weeks earlier on a longer trajectory due to the different aspects of its mission.

Voyager 1 has entered interstellar space and Voyager 2 is expected to do so in 2019-2020 (the two spacecraft are traveling at different speeds along different trajectories). Both spacecraft continue to operate and make observations.

Here are some resources to help you celebrate the anniversary. Let me know if you have any questions, and enjoy!

Fun fact: just one year after the Voyager launched, I was present at Cape Canaveral with my family to watch the launch of Pioneer Venus 2. The Pioneer Venus missions represented the first detailed investigation of our sister planet.

NASA Voyager Home Page:
https://voyager.jpl.nasa.gov/

Space.com Voyager Anniversary:
https://www.space.com/38036-celebrate-voyager-with-free-posters-and-scientist-stories.html

NYT Magazine article on Voyager Anniversary:
https://www.nytimes.com/2017/08/03/magazine/the-loyal-engineers-steering-nasas-voyager-probes-across-the-universe.html

New Yorker article on Voyager’s Golden Record:
https://www.newyorker.com/tech/elements/voyager-golden-record-40th-anniversary-timothy-ferris

Guardian article on Voyager Anniversary:
https://www.theguardian.com/science/2015/mar/15/voyager-1-and-2-space-journey-nasa

Atlantic Voyager photo gallery:
https://www.theatlantic.com/photo/2017/08/voyagers-40th-anniversary/536493/

Voyager question from xkcd What If?
https://what-if.xkcd.com/38/

A famous 1979 image taken by Voyager 1 of Jupiter and Europa:
https://apod.nasa.gov/apod/ap170905.html

Voyager posters and infographics for you to download:
https://voyager.jpl.nasa.gov/downloads/

Voyager Twitter:
https://twitter.com/NASAVoyager

YouTube:

JPL: Voyager at 40:
https://youtu.be/C1UBg4TPqX4

NASA Von Karman Lecture: Voyager: 40 Years in Space:
https://youtu.be/nPSQcXs3DJI

Universe Today: Where is Voyager now?
https://youtu.be/AbZ-6CcKw5M

Vox: Voyager and the distances involved:
https://youtu.be/wgDr26MvWKQ

NASA Briefing 1990: Ed Stone and Carl Sagan discuss the Voyager missions (long):
https://youtu.be/ZQCTgCF8Khk

The Night Sky in June

Greetings skywatchers! There are some exciting events coming this month so let’s take a look:

Today’s Full Moon (9:09 am ET/8:09 am CT/6:09 am PT) is sometimes known as the Strawberry Moon; the Algonquins used this Moon as a reminder to begin harvesting fruit that had ripened.

[Note: The image above depicts the southeast sky at 10 pm ET. The red line represents the ecliptic (the apparent path of the Sun on the celestial sphere). I created this image using Stellarium]

Remember the “Supermoon”? Well, the day before this month’s Full Moon is lunar apogee, when the Moon reaches the farthest point in its orbit around Earth. Consequently, the Full Moon on Friday will be the smallest of the year and is (unofficially) known as a “Minimoon” or “Micro-moon.” Will it be noticeably smaller than a normal Full Moon? Well the difference in angular size between a Supermoon and a Minimoon is only about 4 arcminutes, which in non-technical terms means you probably won’t notice unless you watch the Moon every night! (1 degree of angular measure on the celestial sphere equals 60 arcminutes).

This Full Moon may have some color to it since it will be the closest Full Moon to the horizon this year. Because the moonlight will pass through more of Earth’s atmosphere, you may see it take on a yellow or faint orange tint.

A bonus on Friday willl be that bright dot to the lower right of the Moon: yes that’s Saturn! You will get to see plenty of Saturn since it will be bounding around the sky throughout June. Most importantly, on June 15 Saturn reaches opposition with Earth. This means that Saturn and the Sun are on opposite sides of Earth and Saturn will be at its maximum brightness for the year.

Saturn at this point is also at its closest point to Earth, which isn’t saying much since this spans a distance of 75 light-minutes or over 9 AU (1 AU = 93 million miles). At such a distance it takes Saturn almost 30 years to complete one orbit around the Sun.

We are lucky this year as it is Saturn’s northern summer solstice, meaning that the planet and its rings will be tilted toward us. This orientation should make for an excellent view through a telescope or even powerful binoculars on a tripod. Saturn of course is much farther away than the Moon; including the ring system Saturn will measure just 42 arcseconds across, so you won’t see much with just your eyes.

[Note: The image depicts the orientation of Saturn toward Earth on June 15. Note the large gap in the ring system (known as the Cassini Division) and the hexagonal north polar region. I created this image using the NASA/JPL Solar System Simulator]

Another interesting fact about this month: there will be two first quarter Moons in June. You probably know that the lunar month is a bit over 29 days long; as a result any month (except February) can have two instances of the same phase. This year there was a first quarter Moon on June 1, and we will see another one at the end of June on the 30th.

The final major event this month is the summer solstice on June 21 (12:24 am ET/11:24 pm CT/9:24 pm PT), which marks the beginning of astronomical summer. This is the longest day of the year in the Northern Hemisphere as the Sun reaches its northernmost declination in relation to Earth, and this circle of latitude is the northernmost point at which the Sun will appear directly overhead. The circle is known as the Tropic of Cancer (just above 23 deg N) because in antiquity the Sun appeared in the constellation Cancer at the summer solstice. Today the Sun appears in Taurus due to precession, but the name remains.

Those of you who are logophiles will take notice of the words “solstice” and “tropic” as they refer to the Sun’s apparent journey in the sky. The word “solstice” comes from the combination of the Latin words sol (sun) and sistere (to stop). Meanwhile the word “tropic” is derived from the ancient Greek word meaning a change or reverse. Thus these two words nicely describe how the Sun stops its northward movement on the solstice and turns back south after reaching the Tropic of Cancer.

Remembering John Glenn

We remember John Glenn as the first American to orbit the Earth, a feat he accomplished in the tiny Mercury capsule Friendship 7 on February 20, 1962. You are probably familiar with this achievement, but but there is much more to Glenn’s story.

John Glenn Audiovisual Collection
Lt. Glenn next to his F4U Corsair, Marshall Islands, 1944

John Glenn enlisted in the Army Air Corps after Pearl Harbor. He later transferred to the Marine Corps and was deployed to the Marshall Islands, where beginning in mid-1944 he flew 59 combat missions in an F4U Corsair against targets in the Pacific. During the Korean War, Glenn flew another 90 combat missions in 1953, for a time flying with Ted Williams of the Boston Red Sox as his wingman.

ss-120216-john-glenn-02n-grid-5x2
Maj. Glenn in the cockpit of his F8U Crusader, 1957

Through the rest of the 1950s, Glenn tested various experimental aircraft as a test pilot with the Navy. In July 1957, he set a new transcontinental speed record when he flew from Los Angeles to New York in 3 hours and 23 minutes.

mercury_s61-00239
John Glenn with Gus Grissom and Alan Shepard at Launch Complex 5, Cape Canaveral, 1961

After his historic Mercury flight, Glenn’s prospects for another space mission were uncertain; It was rumored that President Kennedy and NASA had decided it was too risky for someone who had become a national hero to fly again. At the recommendation of Robert Kennedy, Glenn was inspired to enter politics, running for senator from Ohio in 1964. Unfortunately he suffered a concussion after an accident, and was forced to withdraw from the race; however in 1974 he ran again and won, eventually serving four terms in the Senate before retiring in 1999.

John Glenn Audiovisual Collection
John Glenn as a crew member on the Space Shuttle Discovery, Mission STS-95, 1998

In 1998 he became at age 77 the oldest human to travel into space. He had to pass all the standard physical exams to qualify for flight status before becoming part of the crew of the Space Shuttle Discovery.

When I worked for the Smithsonian I would pass by Friendship 7 on the way to work every morning. It’s easy to look at the little capsule today and reflect on how modest and tentative our first steps into space were. Yet thanks to John Glenn and his fellow pioneers, we are exploring the planets and perhaps, some day, the stars.

Here is an excellent one-hour documentary about the journey of Friendship 7 produced for NASA and shown in theaters across the country in 1962. Although many Americans (including this humble writer) are too young to recall the Mercury Seven and their historic flights, this film captures a little of the excitement that must have marked the early years of the Space Age.

First American in Orbit, 1962

If you are interested in Project Mercury, here are several other NASA films from the period. Thanks go to Jeff Quitney for restoring and posting these and many other films to YouTube.

Overview of Project Mercury, 1960

Status of Project Mercury, 1962

Summary of Project Mercury, 1963

Photo credits: (1,4) Ohio State University; (2) Flying Leatherneck Historical Foundation; (3) NASA.

Blue Moon and Mars Opposition

Greetings Skywatchers! This is a special weekend in that not only is there a Blue Moon arriving on Saturday, it will be travelling through the night sky with Saturn and Mars. In addition, Mars is in opposition this weekend, meaning it will be closer to Earth than usual.

If you have read my emails in the past, you may recall that last summer we had one type of Blue Moon, a CALENDAR Blue Moon when there are two Full Moons in the same calendar month. This weekend we get the other type, a SEASONAL Blue Moon which is when there is an extra Full Moon during an astronomical season.

We define astronomical seasons by the equinoxes and solstices, as opposed to the familiar meteorological seasons used in weather forecasting and school calendars. Astronomically we are in the spring season which extends from the vernal equinox in March to the summer solstice in June. When there are four Full Moons in an astronomical season rather than the usual three, the fourth Moon is known as a Blue Moon.

Blue Moons by either definition are fairly common (and not rare as the popular expression would have you believe). However, it so happens that there will be no Blue Moons at all in 2017, so enjoy this one!

Why is this Moon called a “blue” Moon? There are many theories but no definitive answer. One frequent claim that I like is that “blue” comes not from the color, but rather from the Old English word “belewe,” which means “to betray.” When the calculations for Easter were developed, they accounted for 12 Full Moons in the year, so when occasionally there was a 13th Moon, it was seen as a “betrayer” by ecclesiastical authorities.

The Blue Moon will share the sky with Mars from twilight on May 21 through to the next morning. While the Moon will not really appear blue, Mars of course really is red, and you may notice that Mars appears somewhat redder than usual. On May 22 (Sunday), Mars will be in opposition with Earth. What does that mean? Well Mars and the Sun are going to be on opposite sides of Earth. When the Sun sets, Mars will rise in the sky, and will set when the Sun rises again Monday morning.

Mars has a highly eccentric orbit compared to Earth; this means that its orbit around the Sun is more elliptical (and therefore less circular) than Earth’s orbit. Because of this, each opposition of Mars occurs at a different distance from Earth.

This opposition will bring Mars closer to Earth than it has been for some time, placing Mars 46.8 million miles (75.3 million km) from Earth, which is pretty close, but not as close as the famous 2003 opposition when it was just 34.7 million miles (55.8 million km) from Earth.

Actually while Sunday is the opposition event, Mars will continue to move closer to Earth all week, until its closest approach comes on May 30. Mars will be even closer at the next opposition in 2018, but if you don’t want to wait, have a look this weekend.

On Saturday, look for the Moon and Mars rising in the east after sunset along with Saturn and Antares, all four of them forming a grand procession through the night. As always, please dress for your local weather and observe night time safety precautions if you will be observing in dark areas. Good luck and have a nice weekend!

Note: The image above depicts the southeast sky after sunset on Saturday, May 21. The red line represents the ecliptic (the apparent path of the Sun on the celestial sphere). I created this image using Stellarium which is available at http://www.stellarium.org/