I knew it would happen someday. NASA officially declared the Mars Opportunity Rover mission was over. It was active for nearly 15 years and had driven more than 26 miles exploring craters, various rock features, and the weather. Last year, a global dust storm on Mars darkened the skies for many weeks. Opportunity went into a hibernation to save power. After the dust settled and the sun returned, multiple efforts to make contact failed.
Previously in 2010, Spirit, the other identical rover, had succumbed to the harsh Martian conditions. Both were launched in 2003. They landed with the aid of airbags to soften the impact. They were ‘warranted’ for 90 day missions. Spirit exceeded that by 20x.
Randall Munroe of xkcd published a nice commemorative cartoon for the occasion. Thanks to the intrepid rover for taking us along during its explorations.
Randall Munroe | xkcd.com
NASA published this short video showing some of the highlights of the Opportunity mission.
How will the Moon look on any date in 2019? What will it look like on your birthday? Find out at NASA Dial-a-Moon. Here is Dial-a-Moon for southern hemisphere readers.
8 Feb 2019
Enter any month and day to see a high definition image. The composite images of Dial-a-Moon are made from those of the Lunar Reconnaissance Orbiter (LRO) in low altitude orbit around the Moon since 2009.
You may leave the universal time (UT) at the default value. Your local to Universal time conversion can be done at this link. Or, type ‘universal time’ into Google. Go back to Dial-a-Moon to enter the UT.
A Year of Moon Motions
The collection of accurate images of the Moon for each hour have been made into the movies below each lasting about 5 minutes. Try watching full screen for the best effect. Versions of the movie are available for readers in the northern and the southern hemispheres.
I explain the Moon’s peculiar wobble and tipping motions at this blog post.
Opinions of people in the United States about climate change range widely. Yale and George Mason Universities surveyed >22,000 people between 2008 and 2018 for the Climate Change in the American Mind project. The survey reveals a lot about beliefs, perceptions, support, and behavior across the country. You can compare your opinions with others in your state, congressional district, metro area, and county.
Funding for the study was provided by the Skoll Global Threats Fund, the Energy Foundation, the 11th Hour Project, the Grantham Foundation for the Protection of the Environment, the MacArthur Foundation, the Overlook Foundation and the Endeavor Foundation.
70% of the respondents agree global warming is happening
49% agree that most scientists think it is happening
70% believe it will harm future generations
41% say it is now harming them personally
79% think schools should teach about climate change
70% say environmental protection is more important than economic growth
The study presents the data in an interactive map of the U.S. Continue reading below where you will find a video tutorial I made showing how to easily use the interactive features of the map. If you prefer to explore on your own, click the map image below to go directly to the study.
The New Horizons spacecraft returned this detailed image of Ultima Thule to Earth on 18-19 Jan 2018. It was captured 7 minutes before the closest approach to Ultima Thule at a distance of 4,200 mi (6,700 km). The signal of digital bits traveled at the speed of light for 6 hrs before reaching the antenna at Earth so we could see it.
The shape of Ultima Thule was discovered in July 2017 when it passed in front of a distant star as seen from Earth. Twenty four telescopes were lined up across Argentina where the shadow of Ultima Thule was to pass as it occulted the distant star. The scopes were coordinated with precise time markers. The best-fit of their timings suggested a bi-lobed object. What an amazing prediction considering UT is only about 20 mi (30 km) across and measured from more than 4 billion miles away.
This is probably the oldest and most primordial object we will ever see in such detail.
Ultima Thule belongs to a class of Kuiper belt objects called the “Cold Classicals,” which have nearly circular orbits with low inclinations to the solar plane, and which have not been perturbed since their formation perhaps 4.6 billion years ago. Ultima Thule will therefore be the most primitive planetary object yet explored, and will reveal to us what conditions were like in this distant part of the solar system as it condensed from the solar nebula.
What’s next for New Horizons? Hopes are high for extensions to the mission into 2019 and beyond. It will take into 2020 to download all the data stored in the memory banks. With remaining fuel, New Horizons might survey the field ahead and redirect slightly to pass by other Kuiper Belt objects. Stay tuned to see what might happen.
Previously, I shared a post about a conversation with my son about the rising sun viewed at different latitudes. During that conversation, we also discussed how the length of our shadow varied over the course of a year. In winter at noon in the northern hemisphere, when the sun is low in the sky, our shadows are cast long to the north. In summer, our shadows are shorter due to the higher angle of the sun in the sky.
Imagine a plane extending through the earth at the equator. Extend that equatorial plane out into space. Between late March and late September, the sun appears above that plane. It reaches its highest extent in late June at the summer solstice. The sun appears at the elevation of the plane on the equinoxes in late March and late September. It appears at its farthest extent below the equatorial plane in late December at the winter solstice. The farthest north and south of the equatorial plane reached by the sun is 23.5˚.
Melanie and I live about 42˚ north of the equator. In the summer months, the sunlight direction is above the equatorial plane several degrees. Our short shadows are cast to the north at noon. In the winter months, the sunlight direction is below the equatorial plane. Our shadows are cast longer to the north. The blue man in this figure is not to scale, but illustrates the concept of casting of shadows.
It was 6:30 pm on 24 Jan 2018. The International Space Station was due to pass directly over our part of Iowa from WSW to NE. It was 3˚F outside with more than a foot of snow on the ground. Instead of going outside, I set the iPad in the bedroom window, closed the door, and recorded the pass for 6 minutes. While I watched the spaceship cruise above the trees at 5 mi/sec, an airship also cruised over at about 0.2 mi/sec. The stars silently observed from their perches. I stayed warm.
NightCap Camera | iPad2 | ISO=1536 | 356 sec | Click to embiggen
I explained to my son how my shadow was cast almost straight down at noon when we were 12˚south of the equator in Peru. That had never happened to me before. Living 42˚north of the equator, we always cast shadows. They are short in the summer when the Sun is high in the sky and long in the winter when the Sun is low. But, never straight down like this.
My son posed a question about sunrises at the equator. “Does the Sun rise straight up due east each day of the year.” I said it doesn’t rise due east every day. But, it does rise nearly straight up. He acted skeptical. It was time to use desktop planetarium software to simulate the view.
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