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Stupid Internet posts: No, gravity won’t be canceled January 4th.
Looks like the hoaxsters are at it again. Seems someone dusted off Sir. Patrick Moore’s April Fool’s joke from long ago and dressed it up as a phony NASA tweet and sent it out 9 days ago. Supposedly on January 4th, 2015 an alignment of Jupiter and Pluto will cancel gravity on the Earth for a few minutes that day. Both Newton and Einstein would be ticked off at that. Neither of their theories of gravity would predict anything so stupid. Besides Jupiter and Pluto are at nearly opposite parts of the sky. They don’t align with anything.
Don’t take my word for it as a lowly amateur astronomer. Check out the (A real astrophysics PhD) Bad Astronomer Phil Plait’s post: http://www.slate.com/blogs/bad_astronomy/2014/12/24/zero_g_day_nope.html.
Here’s a post from EarthSky with the same sentiments.
However January 4th, 2014 is special. It’s Perihelion Day, the day of the year the Earth is closest to the Sun. So break out the sunscreen, especially if you live in the southern hemisphere, where it’s summer now. The biggest effect we’ll see is that winter is the shortest season for us by a couple of days compared to summer, the longest season. The Earth moves its fastest in it’s orbit of the Sun at perihelion.
07/10/2014 – Ephemeris – Why is the bright Moon so low in summer and so high in winter?
Ephemeris for Thursday, July 10th. Today the sun will be up for 15 hours and 20 minutes, setting at 9:28. The moon, 2 days before full, will set at 5:22 tomorrow morning. Tomorrow the sun will rise at 6:08.
If you watch the moon for the next few nights, you won’t have to strain your neck because the moon at its highest will be less than 30 degrees above the southern horizon for us in northern Michigan. That’s because the moon closely follows the path of the sun in the sky, called the ecliptic, with a deviation of only 5 degrees maximum. Tonight it’s a couple of degrees north of the ecliptic. Tonight it’s located about where the sun was back last November or will be next November. In winter you’d swear that the full moon at its greatest height was practically overhead. It’s another effect of the Earth’s axial tilt of 23 ½ degrees. Our moon is odd in it doesn’t orbit the Earth’s equator like most large moons do for their planets.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The full Moon on July, 12, 2014. Created using Stellarium.
The full Moon on December 6, 2014. Created using Stellarium.
06/20/2014 – Ephemeris – Summer is almost here!
Ephemeris for Friday, June 20th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, 1 day past last quarter, will rise at 2:21 tomorrow morning. Tomorrow the sun will rise at 5:57.
Summer will begin at 6:52 tomorrow morning. Great I can’t wait. Summer is my favorite season, and it is especially welcome after the long and cold winter, and a not especially warm spring. In the summer I move my operations to a table under a tree in the back yard, with a laptop and my radio tuned to IPR, of course. There I conduct my research, take online teleconferences and courses and do my writing. The summer solstice for us in the northern hemisphere is when the sun reaches its farthest north in the sky. Around the Interlochen/Traverse City area that’s about 68.5 degrees above the southern horizon at solar noon, which is about 1:43 p.m. and staying up 15 hours and 33 minutes.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The earth centered on Michigan at 6:52 a.m. EDT, June 21, 2014 the moment of the summer solstice. Created using Celestia.
My summer office
06/16/2014 – Ephemeris – Dates of the earliest sunrise and latest sunset
Ephemeris for Monday, June 16th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:29. The moon, half way from full to last quarter, will rise at 12:11 tomorrow morning. Tomorrow the sun will rise at 5:56.
Yesterday saw the earliest sunrise for the year. My sunrise times will start to show a change on Thursday. The day-to-day change in sunrise times are now a few seconds. The summer solstice, or longest day will be this Saturday, and the latest sunset won’t occur until next week Thursday. The reason these dates don’t coincide has to do with the tilt of the earth’s axis and the earth’s slightly elliptical path around the sun. Actually the disparity between these dates is more pronounced at the winter solstice when the Earth is closer to the sun and moving faster. Yup, the sun is farther away now than it was in December. Actually we’re moving slower now, so summer lasts a few days longer than winter.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
03/20/2014 – Ephemeris – Spring is a few hours away
Ephemeris for Thursday, March 20th. The sun will rise at 7:45. It’ll be up for 12 hours and 9 minutes, setting at 7:54. The moon, 3 days before last quarter, will rise at 12:24 tomorrow morning.
Just hang on for a few more hours and winter will be over. At 12:57 p.m. this afternoon (16:57 UT, March 20, 2014) the sun will appear to cross the earth’s celestial equator heading northward signaling the start of spring in the northern hemisphere. Unfortunately our weather won’t change that instantaneously. The word equinox means equal night, meaning at day and night are of equal length. However due to how astronomers actually define the instant of sunrise and sunset we are already above 12 hours daylight, and increasing by 3 minutes a day. The southern hemisphere of the earth will see the start of autumn as we see spring. The sun will rise due east today and set due west, which may mean hazardous visibility on east west roads with the low sun for a few days.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The sun at the vernal equinox point in the sky. The horizontal line the sun is crossing is the celestial equator. The red line is the sun’s path, the ecliptic. The sun is heading to the upper left. Created using Stellarium.
12/20/2013 – Ephemeris – Winter begins tomorow
Ephemeris for Friday, December 20th. The sun will rise at 8:15. It’ll be up for 8 hours and 48 minutes, setting at 5:04. The moon, 3 days past full, will rise at 8:32 this evening.
The thermometer and snowfall tell us that winter ought to be here. Well it will be at 12:11 p.m. (17:11 UT) tomorrow afternoon. At that point the sun will be directly over the Tropic of Capricorn at 23 ½ degrees south latitude. Odd name because 2,000 years ago the sun was in indeed entering Capricornus. Now it’s entering in Sagittarius, right above the spout of the teapot asterism we know so well in summer. From then on the sun will be climbing up the sky each noon until June 21st next year when summer will start. To which I say Go Sun Go! The sun will barely make it to 22 degrees above the southern horizon at local noon in Interlochen and be out for only 8 hours and 48 minutes. If it stayed there all year we’d be in a deep freeze colder than Antarctica.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Sun’s view of the Earth at the instant of winter solstice. Created using Celestia.
06/26/2013 – Ephemeris – Latest sunset and the Summer Triangle
Ephemeris for Thursday, June 27th. Today the sun will be up for 15 hours and 32 minutes, setting at 9:31. The moon, 3 days before last quarter, will rise at 12:14 tomorrow morning. Tomorrow the sun will rise at 5:59.
Last night we had the latest sunset of the year. The sun is really beginning to head south. Other than the sunrise and sunset numbers, we’ll begin to notice it for real in a few weeks. At first that realization strikes me a sad note that summer is beginning to end. However the astronomer in me realizes that means more night-time hours, and that the summer Milky Way is coming. Of the three bright stars of the Summer Triangle overhead and in the east, two of its stars are in the milky band. They are Deneb to the north and Altair to the south. Vega, closest to the zenith is not in the band. Actually all the stars we see with the naked eye or small telescopes belong to the Milky Way galaxy.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Summer Triangle at 11 p.m. Created using Stellaruim and The Gimp.
06/21/2013 – Ephemeris – Seasons and the height of the sun
Ephemeris for Friday, June 21st. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, 2 days before full, will set at 5:11 tomorrow morning. Tomorrow the sun will rise at 5:57.
Happy summer. It began at 1:04 this morning. The sun is at its highest at noon, well local solar noon that is, which is 1:44 p.m. in the Interlochen Traverse City area. At that time the sun will reach an altitude or angle above the southern horizon of nearly 69 degrees. If you want to get an idea of the difference between that and the sun at the winter solstice, check out the moon tonight. It is almost to the point in the sky where the sun was at the winter solstice. Notice how low it is in the sky, and how few hours it is up. The cause is the tilt of the earth’s axis of 23 and a half degrees. It gives us a 47 degree span of altitudes of the sun over the year. It is not the sun’s distance that causes seasons, as we’ll see next month.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comparing the sun’s path at the summer and winter solstices. This is a stereographic representation of the whole sky which distorts the sky and magnifies the size of the sun’s path near the horizon.
06/20/2013 – Ephemeris – Summer starts tomorrow
Ephemeris for Thursday, June 20th. Today the sun will be up for 15 hours and 33 minutes, setting at 9:31. The moon, 3 days before full, will set at 4:15 tomorrow morning. Tomorrow the sun will rise at 5:57.
Summer will arrive overnight at 1:04 a.m. tomorrow morning when the sun will reach its highest point in the northern sky. If you were watching the sun’s shadow of a flag pole at local noon, when the sun is due south, it would be getting shorter every day since the winter solstice back on December 21st. From tomorrow until the next winter solstice that shadow will be getting longer. We are getting the most heat from the sun now due to the length of daylight and the high altitude of the sun most of the day. Because the earth and water takes time to heat up, we are not experiencing our greatest temperatures yet. That will take a month or a month and a half. That’s why solstice just starts summer and is not at the peak of it.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Comparison of shadows between winter and summer solstices. Note the angles are approximate.
06/14/2013 – Ephemeris – Earliest sun rise of the year
Ephemeris for Flag Day, Friday, June 14th. Today the sun will be up for 15 hours and 32 minutes, setting at 9:29. The moon, 2 days before first quarter, will set at 12:51 tomorrow morning. Tomorrow the sun will rise at 5:56.
The sundial makes a poor clock. It will give the approximate time, but even if you could make the lines on its face accurate for one day, it could be off a week later. The reason I mention this is because tomorrow morning is the earliest sunrise. We’ll be still 6 days from the longest day, when the daylight hours are at their maximum. The latest sunset will be on the 26th, 5 days after the summer solstice. The disparity is even greater in the winter. Sundials can be corrected by a table of how much the sun is fast or slow, called the equation of time. It is caused by both earth’s slightly eccentric orbit of the sun, and the tilt of the earth’s axis. It seems when you study things closely they are not as simple as they appear.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Bob Moler's Ephemeris Blog 