A Day in Astronomy: Orbiting Mercury

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Image (Credit): Artist’s image of MESSENGER orbiting Mercury (NASA).

On this day in 2011, NASA’s MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) probe became the first spacecraft to orbit Mercury. NASA prepared the 10-year summary below explaining MESSENGER’s accomplishments from the time it was launched on August 3, 2004 through August 1, 2014. The probe later impacted the surface of Mercury on April 30, 2015.

NASA issued this high-level summary of the mission:

The MESSENGER spacecraft fundamentally changed our understanding of Mercury during its four-year orbital exploration of the planet, returning nearly 300,000 photographs and a wealth of information from its instruments. The formatted data totaling more than 10 terabytes reside in NASA’s Planetary Data System archive. Among the major findings were that Mercury harbors water ice and organic compounds at its north pole, that volcanism played a major role in shaping the planet’s surface, and that Mercury’s surface materials are more volatile-rich and chemically reduced than expected.

Image (Credit): 10-Year Summary of MESSENGER’s activities as of August 1, 2014. (NASA)

Pic of the Week: Spanish Dancer Galaxy

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Image (Credit): Spanish Dancer Galaxy (Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA)

This week’s image, from the Cerro Tololo Inter-American Observatory in Chile, is nicknamed the Spanish Dancer Galaxy. Here is a little more on from the National Science Foundation’s (NSF) National Optical-Infrared Astronomy Research Laboratory (NOIRLab):

Located in the constellation Dorado and lying around 70 million light-years away, NGC 1566 is a grand-design spiral galaxy with two arms that appear to wind around the galactic core, just like the arms of a dancer as they spin around and around in a furious twirl. This image was taken from Chile at the Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, using the Dark Energy Camera. The galaxy’s face-on view to us, its location, and its composition make it a trove of observational opportunities for astronomers across many fields of astronomy.

NGC 1566 is home to stars at all stages of stellar evolution. In this image, the bright blue color that outlines the arms of the galaxy arises from young, brightly burning stars. Darker spots within these arms are dust lanes. The arms are rich in gas, and form large-scale areas that provide the perfect environment for new stars to form. Closer to the center of the galaxy are cooler, older stars and dust, all evident by the redder color in the image. This galaxy has even been host to an observed stellar end-of-life event, when a supernova, named SN2010el, burst onto the scene in 2010.

The center of NGC 1566 is dominated by a supermassive black hole. The distinct and highly luminous nucleus of the galaxy is known as an active galactic nucleus. The light from the nucleus changes on timescales of only hundreds of days, making its exact classification difficult for astronomers. 

A Space Telescope Goes Dark

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Image (Credit): Picture of the completely integrated mirrors and detectors before final packaging. (Max Planck Institute for Extraterrestrial Physics)

You may have heard of Germany’s black hole-hunting telescope called the extended ROentgen Survey with an Imaging Telescope Arraye (eROSITA). It was launched in 2019 as part of a larger Russian-German mission called the “Spectrum-Roentgen-Gamma” (SRG) observatory and placed in the L2 Lagrange Point.

The eROSITA has three primary goals:

  • to detect the hot intergalactic medium of 50-100 thousand galaxy clusters and groups and hot gas in filaments between clusters to map out the large scale structure in the Universe for the study of cosmic structure evolution,
  • to detect systematically all obscured accreting Black Holes in nearby galaxies and many (up to 3 Million) new, distant active galactic nuclei and
  • to study in detail the physics of galactic X-ray source populations, like pre-main sequence stars, supernova remnants and X-ray binaries.

Well, similar to other joint Russian space missions, the telescope’s work was put on hold because of continuing events in Ukraine. The German government had this to say:

[Deutsches Zentrum für Luft- und Raumfahrt (DLR)] and the German Space Agency at DLR have been cooperating with Russian institutions on a number of research projects, in some cases with the participation of other German research organisations and universities, and international partners.

Against the backdrop of the aggressive attack on Ukraine, the DLR Executive Board is taking the following measures:

  • All collaboration activities with Russian institutions on current projects or projects in the planning stage will be terminated.
  • There will be no new projects or initiatives with institutions in Russia.

Where necessary, DLR will enter into coordination with other national and international partners.

We are slowly blocking our view of the bigger universe because of the reckless actions of a few. Hopefully, we can open up our eyes again shortly.

Exoplanet or Star?

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Image(Credit): Kepler-854b (NASA Exoplanet Exploration).

Phys.org had a good story on the reclassification of objects captured by the NASA’s Kepler Space Telescope once believed to be exoplanets. New evidence indicates three “exoplanets” – Kepler-854b, Kepler-840b, and Kepler-699b – are actually stars (hence, the NASA image above will need to be modified).

The article notes that the three objects are too large to be considered planets, being between two and four times the size of Jupiter. The results were part of a study from the Astronomical Journal. A fourth exoplanet, Kepler-747 b, might also be a star.

After updated information indicated Kepler-854b was about three times the size of Jupiter, one of the study authors said, “There’s no way the universe can make a planet of that size…It just doesn’t exist.”

While the team reviewed about 2,000 Kepler exoplanets to find these four questionable items, it is likely that more will be found in the future among other reported exoplanets. Fortunately, that still leaves us with plenty of real exoplanets to study.

The Future of the International Space Station

Posted on by onespaceman2000
Image(Credit): Northrop Grumman’s Cygnus space freighter approaching the International Space Station (NASA).

Over the weekend, the Washington Post published an editorial by Homer Hickam, former NASA engineer and advisor to the National Space Council, titled, “Our space partnership with Russia can’t go on.” In the piece, Mr. Hickam argues that the International Space Station (ISS) has accomplished its goals and the US can now move onto other projects without the Russians:

With our flourishing commercial space companies, who are already cutting metal on their own future space stations, plus our federal government’s Artemis moon program, the United States is entering a new golden age of space exploration. The Russians, meanwhile, are stuck in the past with antiquated spacecraft and nowhere to go except the ISS.

Mr. Hickam appears to believe pushing out the Russians may mean the end of the ISS. Of course, this is just one man’s view, and whatever we do we need to do it in conjunction with our other ISS partners.

We could continue to maintain the ISS through 2030, as planned, and schedule more useful science even without the Russians as partners. This may make sense until we have another viable station that we can use, such as NASA’s planned lunar Gateway. Russia will not be part of the Gateway given that it is working with China on other lunar plans, so we do not need to worry about another breakup.

It would be better if Russia had focused on its space accomplishments rather than territorial ambitions as it prepares for the future. Joint space programs are a great way to use rockets for peaceful missions. I am not against a space race that pushes us even farther into space, yet I would prefer it be fueled by scientific achievement rather than nationalist angst.

Image(Credit): Artist rendering of the Artemis lunar Gateway (NASA).