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05/16/2022 – Ephemeris – A peek at the monster at the center of the Milky Way

May 17, 2022 Comments off

This is Ephemeris for Tuesday, May 17th. Today the Sun will be up for 14 hours and 54 minutes, setting at 9:06, and it will rise tomorrow at 6:11. The Moon, 1 day past full, will rise at 11:33 this evening.

This past Thursday the Event Horizon Telescope Collaboration released an image of the black hole at the center of the Milky Way, 27,000 light years away In the direction of the constellation of Sagittarius, which is currently visible low in the south in the morning hours. How they got the image is too complex to explain here, not that I know how they did it. It appears as a fuzzy donut with three bright areas around the edges. The dark center is the shadow of the black hole, because no light can escape it, plus it severely bends any light that comes near it. The light we’re seeing it is in millimeter microwaves, rather than the nanometer wavelengths of visible light. Part of the fuzziness of the image is due to the motion of the material surrounding it.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Milky Way Black Hole

This is the image released May 12, 2022 by the Event Horizon Telescope Collaboration.

M87 compared to Sagittarius A*

M87* size compared to Sagittarius A*. The size of a black hole is directly related to its mass. The asterisk * is pronounced “Star”. Credit: Event Horizon Telescope Collaboration.

It looks like I’ll have to update my presentation, What Lurks in the Center of the Milky Way? Astronomers were already sure it was a black hole, but the donut appearance of Sagittarius A* clinched it.

Off topic

Lunar eclipse shortly after the partial eclipse began

Last night’s (May 15/16) lunar eclipse, shortly after the partial eclipse began behind clouds. I often checked until totality, but it seems to get worse. I may have missed brief clearings. When I got up, it was clear… Figures.

05/10/2022 – Ephemeris – Event Horizon Telescope Collaboration will announce “groundbreaking Milky Way results” on Thursday

May 10, 2022 Comments off

This is Ephemeris for Tuesday, May 10th. Today the Sun will be up for 14 hours and 38 minutes, setting at 8:58, and it will rise tomorrow at 6:19. The Moon, 2 days past first quarter, will set at 4:25 tomorrow morning.

This Thursday, May 12th at 13:00 UT (9 am our time EDT) the Event Horizon Telescope Collaboration will announce “groundbreaking Milky Way results.” Their words. Their first groundbreaking result came in three years ago with the release of an image of the billion solar mass black hole in the heart of the giant galaxy M 87 over 50 million light years away. Beforehand, I was expecting the results to concern a more nearby black hole called Sagittarius A* (pronounced Sagittarius A Star) at the center of our galaxy, only 25 to 27 thousand light years away. That turned out to be much more difficult than the one in M 87, due to the amount of dust and gas in the way. So maybe this time they have done it. We’ll all find out this Thursday.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hours). They may be different for your location.

Addendum

Black hole in M87

The first image of the black hole in M87. Credit Event Horizon Telescope.

The Event Horizon Telescope isn’t a single telescope. But millimeter wavelength radio telescopes spaced out to use the diameter of the Earth as its simulated aperture. The ability to resolve tiny objects at great distances depends on the wavelength of the radiation and the size of the telescope aperture. So the smaller the wavelength and the larger the aperture, the greater the resolution of the telescope or array.

The observation of all the telescopes must be performed at the same time, recording the observations on terabyte magnetic disks. The disks are brought to a single location for processing together to actually produce the image, which takes a while.

Event Horizon Telescope

Event Horizon Telescope component radio telescopes. Credits: © APEX, IRAM, G. Narayanan, J. McMahon, JCMT/JAC, S. Hostler, D. Harvey, ESO/C. Malin.

12/28/2021 – Ephemeris – The James Webb Telescope is on its way to L2

December 28, 2021 Comments off

This is Ephemeris for Tuesday, December 28th. Today the Sun will be up for 8 hours and 50 minutes, setting at 5:09, and it will rise tomorrow at 8:19. The Moon, 2 days past last quarter, will rise at 3:18 tomorrow morning.

The James Webb Space Telescope was launched Christmas morning and is heading out past the Moon’s orbit. It was launched from the European Space Agency’s Spaceport in Kourou, French Guiana on the northeast coast of South America, as part of their contribution to the project. It will orbit a point called Lagrange Point 2, or L2 for short, over four times the Moon’s distance in a direction opposite of the Sun. It will take the telescope 29 days to unfold itself. First order of business was to unfold the solar panels to obtain power, then to deploy its high gain antenna for communications with the Earth. Next to begin to deploy a 5 layer, tennis court sized sun shield. After that, the telescope will be unfolded.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EST, UT – 5 hours). They may be different for your location.

Addendum

The last view of Webb as it separated from the Ariane 5 launch vehicle

The last view of Webb as it separated from the Ariane 5 launch vehicle. Credit: NASA.

07/22/2021 – Ephemeris – Hubble’s trouble is fixed

July 22, 2021 Comments off

This is Bob Moler with Ephemeris for Thursday, July 22nd. Today the Sun will be up for 15 hours even, setting at 9:19, and it will rise tomorrow at 6:19. The Moon, 1 day before full, will set at 5:18 tomorrow morning.

Folks at NASA are breathing a sigh of relief. After a month when one of its computers failed in the Hubble Space Telescope, ground controllers were able to diagnose that the problem was actually in the computer and not somewhere else. They switched to a backup computer. This wasn’t the main computer, but the one that ran the instruments. Hubble resumed operations this past Sunday. Hubble’s more or less replacement, the James Webb Space Telescope is many years overdue to be launched, and is expected to be launched later this year by the European Space Agency from French Guiana, as their contribution to the project. The Webb telescope operates in the infrared, while Hubble operates mostly in visible light.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT – 4 hr). They may be different for your location.

Addendum

The Hubble Space Telescope

The Hubble Space Telescope after its last servicing mission. Credit: NASA.

 

Full scale model of the JWST at Goddard Space Flight Center

Full scale model of the James Webb Space Telescope at Goddard Space Flight Center. Note its scale with the people in front of it.

11/05/2020 – Ephemeris – Water found on the daylit side of the Moon

November 5, 2020 Comments off

This is Ephemeris for Thursday, November 5th. Today the Sun will be up for 9 hours and 58 minutes, setting at 5:25, and it will rise tomorrow at 7:28. The Moon, 3 days before last quarter, will rise at 8:55 this evening.

Last week NASA announced some results from their SOFIA airborne observatory. They had detected the spectral signature of water in a large crater on the Moon named Clavius. This was a high latitude crater, 58.6 degrees south. Supposedly one could process a cubic meter of the regolith to extract a half liter of water. Clavius, which science fiction fans will note was the location of the American base on the Moon in 2001 a Space Odyssey. It is also one of my favorite lunar craters, one of the largest with a distinctive arc of diminishingly sized craters in its floor. As far as resources go, we’ve just literally scratched the surface of the Moon in its equatorial regions with our Apollo and other country’s robotic missions.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Moon with Clavius circled

The Moon as seen from Australia (south up) with the crater Clavius circled. This is the same view of the Moon that users of a Newtonian reflector telescope in the northern hemisphere see, and how I first explored the Moon with my reflecting telescope. Source abc.net.au.

Closeup of Clavius

Closeup of Clavius from the Lunar Reconnaissance Orbiter. Credit: NASA/LRO.

Sophia Airborne Observatory

The SOFIA Airborne Observatory. A modified Boeing 747 with a 106 inch (2.7 meter) telescope mounted crosswise in its fuselage. It is a joint project between NASA and the German Aerospace Center (DLR) and for some reason always on the verge of being canceled. Credit: NASA.

SOFIA is of course an acronym for Stratospheric Observatory for Infrared Astronomy. For more on SOFIA click here: https://www.nasa.gov/mission_pages/SOFIA/index.html.

09/24/2020 – Ephemeris – Phosphine found in Venus’ atmosphere

September 24, 2020 Comments off

This is Ephemeris for Thursday, September 24th. Today the Sun will be up for 12 hours and 2 minutes, setting at 7:35, and it will rise tomorrow at 7:34. The Moon, 1 day past first quarter, will set at 12:49 tomorrow morning.

Three years ago astronomers began to discover phosphine in the atmosphere of Venus. The chemical phosphine is related to ammonia in that it has three hydrogen atoms. They are tied to phosphorus rather than to nitrogen as is ammonia. It can also be created biologically, as it is almost entirely created on the Earth. It also is produced by volcanoes, and Venus has evidence of volcanic action. After three years of observation and looking for and ruling out non biological origins of phosphine they made public the announcement last week Monday. The detection was made in the millimeter wavelengths of the electromagnetic spectrum between microwave and the infrared. Is life responsible? A space probe or many to Venus will be needed to find out to help solve the mystery.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Clouds on the night side of Venus

Clouds on the night side of Venus as seen in the infrared from the Japanese spacecraft Akatsuki, the only active spacecraft currently orbiting Venus. Credit JAXA / ISAS / DARTS / Damia Bouic

Some links for more information:

Original article – https://www.nature.com/articles/s41550-020-1174-4,

From Phil Plait’s Bad Astronomy: https://www.syfy.com/syfywire/so-astronomers-may-have-found-evidence-of-life-on-venus

05/30/2019 – Ephemeris – Is the Beta Taurid meteor swarm hiding bigger space rocks?

May 30, 2019 Comments off

Ephemeris for Thursday, May 30th. Today the Sun will be up for 15 hours and 17 minutes, setting at 9:19, and it will rise tomorrow at 6:01. The Moon, half way from last quarter to new, will rise at 4:46 tomorrow morning.

A rather interesting piece of news popped up in astronomical circles last Friday. A paper accepted for publication by David Clark, Paul Wiegert and Peter Brown all of the University of Western Ontario, Canada talked about the prospects of observing the meteoroid swarm out in space that may have contained the famous Tunguska object that hit Siberia in 1908. The swarm has been shed by Encke’s Comet over time. The Earth is due to pass close to the center of the swarm this year in June, something that last happened in 1975. They cause the daytime outbound Beta Taurid shower in June and July and the inbound North and South Taurid showers in autumn.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Screen shot from video by David Clark of the Beta Taurid meteor swarm. Click on image to see video.

Links:

Bad Astronomy’s take on all this: https://www.syfy.com/syfywire/could-larger-space-rocks-be-hiding-in-the-beta-taurid-meteor-stream-we-may-find-out-this

The original paper: https://arxiv.org/pdf/1905.01260.pdf

The article at Spaceweathe.com: https://spaceweatherarchive.com/2019/05/24/close-encounters-with-the-taurid-swarm/

04/10/2019 – Ephemeris Extra – Event Horizon Telescope reveals the black hole in galaxy M87

April 10, 2019 Comments off

At 10 a.m. I found the live feed from the National Science Foundation presenting the results of the Event Horizon Telescope.  It was one of four simultaneous presentations around the world at that hour.  The buzz beforehand was that they would present the image of the black hole in our galaxy Sagittarius A*.  It was not.  The image presented was of the black hole in the galaxy M87, some 55 million light years away.  It turns out that The black hole in M87 is easier to image.  Our black hole appears to be too variable in brightness for this first attempt.  The M87 black hole has a mass of 6.5 billion times that of our sun.  Our black hole has a mass of about 3 million suns.  The size of a black hole’s event horizon is proportional to its mass.  So the M87 black hole is about 2,000 times larger than our black hole, but about 2,000 times farther away.  So they would appear to be the same size on the sky.

Black hole in M87

The first image of the black hole in M87. Credit Event Horizon Telescope/Katie Bouman*.

The round spot in the center is not a shadow, but the event horizon itself.  It is black because no light can escape it.  The ring around it is the accretion disc of material spiraling in to the black hole.  I believe the disc is close to perpendicular to our line of sight, but not close.  The brightest part near the bottom is material that is approaching us, while the dimmer part above is material flowing away.

There are many articles and a video of the news conference by pointing you favorite search engine to M87 black hole.

About M87:  More formally Messier 87, is a galaxy near the center of a vast cluster of galaxies about 55 million light years from us.  Charles Messier found it in 1781 while searching for comets.  He recorded it as object number 87 on his list of fuzzy objects that didn’t move and thus were not a comet.   We amateur astronomers use his Messier Catalog to view these, what we call, deep sky objects.  M87 is a giant elliptical galaxy that was also a radio source called Virgo A.

The Wikipedia article Messier 87 has already been updated to include the results presented of earlier today.

* Update:  Dr. Katherine Bouman AKA Katie Bouman lead the team that created the algorithm that processed the data from the eight radio telescopes of the Event Horizon Telescope.  Her ideas on how to perform this feat of mathematical and computer wizardry were presented in a TED Talk in 2016.

04/09/2019 – Ephemeris – Tomorrow we may be able to see the supermassive black hole at the center of our galaxy

April 9, 2019 Comments off

Ephemeris for Tuesday, April 9th. Today the Sun will be up for 13 hours and 10 minutes, setting at 8:20, and it will rise tomorrow at 7:07. The Moon, 3 days before first quarter, will set at 1:00 tomorrow morning.

There’s a great bit of excitement in astronomical circles for tomorrow’s release of an image of the event horizon of the supermassive black hole at the center of our Milky Way Galaxy, 27 thousand light years away. The black hole is designated Sagittarius A*. Pronounced Sagittarius A Star.  Sagittarius is the constellation it’s located in, capital A for the first radio source found in that constellation and an asterisk, pronounced Star. Eight highly accurate radio telescopes located from Greenland to the south pole, from Hawaii to Europe simultaneously record signals and record them to computer disks. The data are processed together to produce an image with the resolving power of a telescope the diameter of the Earth. The event horizon is smaller than our solar system.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Event Horizon Telescope

Event Horizon Telescope component radio telescopes. Credits: © APEX, IRAM, G. Narayanan, J. McMahon, JCMT/JAC, S. Hostler, D. Harvey, ESO/C. Malin

For more information see this news article from the AAAS Science Magazine:  https://www.sciencemag.org/news/2019/04/here-s-what-scientists-think-black-hole-looks.

For a non-technical explanation of black holes and the event horizon check this out:  https://www.sciencealert.com/black-holes.