Mars Slides Behind Moon This Month

In mid-February, a waning crescent Moon glides among Mars, Jupiter, and Saturn in the predawn sky. For many viewers in North America, the Moon actually covers Mars on February 18th.
Sky & Telescope

It’s fitting that with my intense focus on Malacandra throughout January that upon finishing the Mythgard Academy class this week I have a major astronomical event featuring Mars to look forward to in less than two weeks.

I can take good advantage of this occultation since I live in the middle of the country just shy of 40 degrees north latitude. If I were visiting my daughter in the Pacific Northwest, I’d have a bit more dark time but might not see it as well being at a more northern latitude at 47 degrees.

Image via IOTA. See the loop at the upper right above North America? As the moon rises in the predawn hours on February 18, 2020, in this part of the world, Mars will covered over by the moon. But, later on before dawn, you can watch Mars reappear from behind the moon’s dark side. Read more.

Actually, not just Mars will be in the spotlight in mid-February. Three planets are center stage in the predawn skies starting February 18th (see first graphic above). Listen to Sky Tour courtesy Sky & Telescope for some viewing tips and other astronomical tidbits for February observing.

Sky Tour Podcast for February 2020

My only concern will be the weather, which in February in Kansas, is dodgy at best.

Keeping my fingers crossed and as always keep looking up!

Welcome to Winter Solstice Eve Morning

Good morning and welcome to the last half day before Winter. Officially, Winter begins tonight after ten o’clock (Central time)

Winter Solstice 2019 Countdown

Enjoy the shortest day of the year because I’m looking forward to the longest, darkest night of the year – every amateur astronomers dream.


Today, my son, daughter-in-law and grandson are driving here from Texas. They left before dawn and we anticipate their arrival late this afternoon.

With the help of my daughter, who arrived earlier this week, my main floor living area is mostly baby proof. And the new furniture was delivered Thursday afternoon. And Friday, Rachelle setup the Christmas tree and last night over home-made pizza we decorated (or rather she decorated because she’s the artistic one).

Rachelle and I will spend part of the day shopping, taking advantage of her Costco membership to stock up on food she can eat (corn allergy) and for the rest of the family as well. While I have a Christmas goose in the freezer, I need to plan for other meals and sides. Instead of just Terry and I to feed, I’ll have three to four times that many to provide for.

So we are ready for family gathering and making new memories until we once again scatter back to our nests for the new year.

Do You Hear What I Hear?

My final astronomy discussion topic attempts to answer “Why are some wavelengths of radio emission better than others in searching for extraterrestrial civilizations?”

Plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation.
Plot of Earth’s atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation.

 

Radio waves can travel immense distances without being significantly altered by interstellar medium.  They penetrate dust and gas and are the logical choice for interstellar communication.  Astronomers have been listening for signs of extraterrestrial life using the radio spectrum since the 1950s and 60s – long before scientists had discovered the means of detecting exoplanets.  But the sheer number of both radio frequencies and directions to search proved daunting and raised question like “Which frequencies should be used to maximize the odds of detecting an alien signal?”

Continue reading “Do You Hear What I Hear?”

Universal Song Remains the Same and Beyond All the Light We Cannot See

For such a small chapter, this week’s topic on Cosmology has some large and deep concepts.  I’m attempting to delve into “How did the period of inflation cause the universe to become homogeneous and isotropic?

Definitions

Big Bang ~ Universe began as an extraordinarily hot, dense primordial atom of energy and caused expansion, just like an explosion.  Before that moment, nothing existed, not even space and time.  Rather, the explosion created spacetime, which continues to expand.  (Comins, 446)

Inflationary Epoch ~ During this epoch, the universe became so large that today we can only see a tiny portion of it and that is limited by the speed of light.  The growth and size of the observable universe occurred in a very brief time.  (Comins, 451)

Cosmic microwave background (CMB) ~ If the universe began with a hot Big Bang, then calculations indicated the energy remnants should still fill all of space today. The entire universe’s temperature should be only a few kelvins above absolute zero.  This radiation’s blackbody spectrum peak should lie in the microwave section of the radio spectrum.  (Comins, 446)

Isotropy of CMB ~ The cosmic microwave background radiation is almost perfectly isotropic – the intensity is nearly the same in every observable direction.  Isotropy isn’t just limited to observed blackbody radiation, but is also found on a large scale when exploring the number of galaxies found in different directions.  (Comins, 448)

Homogeneity ~ The uniformity with distance (the numbers of galaxies stays roughly constant with respect to both distance and direction) of the universe is homogeneous. (Comins, 449)

Fine-Tuning Big Bang

Any viable theory of cosmology, including the Big Bang, must explain the isotropy and homogeneity of the universe.  Numerous refinements have been posited and as a result the theory now provides an accurate scenario for the evolution of universe from a tiny fraction of a second after it formed and onward to today.  (Comins, 449) Continue reading “Universal Song Remains the Same and Beyond All the Light We Cannot See”

Just A Sun-Day Drive Around the Galactic Neighborhood

This week I’m tackling the subject of our Sun’s motion through the Milky Way Galaxy and approximately how long one orbit is.

The Milky Way Galaxy has two major spiral arms, named the Perseus Arm and the Scutum-Centaurus Arm.  There are also smaller less pronounced arms, including the Sagittarius Arm, the Norma Arm, The Local Arm (aka the Orion Spur) and the Outer Arm.  Our solar system resides in the Orion Spur (Local Arm), branching off from the larger Perseus Arm.  During the summer months in the northern hemisphere, we predominantly observe the Sagittarius Arm, including the galactic center, which appears as steam from the Tea Pot asterism in the constellation Sagittarius.  (Gaherty, 2016)  Over the winter, we’re looking away from the galactic center and through the Perseus Arm.  (Comins, 396)

Artist’s concept of what astronomers now believe is the overall structure of the spiral arms in our Milky Way galaxy. The sun resides within a minor spiral arm of the galaxy, called the Orion Arm. Image via NASA and Wikimedia Commons.

Continue reading “Just A Sun-Day Drive Around the Galactic Neighborhood”

Stellar Death Blasts

This week I discuss types of supernovae, specifically relating to the scenario where “Hydrogen lines are prominent in Type II supernovae but absent in Type Ia.  Type Ia supernovae decline gradually for more than a year, whereas  Type II supernovae alternate between periods of steep and gradual declines in brightness. Type II light curves therefore have a step-like appearance.  Explain!”

Supernovae are classified as Type I or Type II depending upon the shape of their light curves and the nature of their spectra.

The question I really wanted to ask is ‘What happened to Type I or Ib?’ and the answer to that question was easily found in this chart:

Supernovae Taxonomy
Supernovae Taxonomy

Continue reading “Stellar Death Blasts”

Absolute Magnitude Luminates Absolutely

This week I want to discuss “What might cause the closer of two identical stars to appear dimmer than the farther one?”

Apparent Magnitude: A measurement of the brightness of stars without regard to their distance from Earth.

  • The scale in use today starts with the star Vega and an apparent magnitude of 0.0
  • Objects brighter than Vega are assigned negative numbers.  For example. Sirius, the night’s brightest star, has an apparent magnitude of -1.44
  • The scale was extended to include the dimmest stars visible through binoculars and telescopes.  For example, a pair of binoculars can see stars with an apparent magnitude of +10

Ignoring distance for a moment, all other things being equal, the closer of two identical stars will appear brighter (have a smaller apparent magnitude) to us than the more distant star.  When we account for the difference in distance, we use either or two measurements:  absolute magnitude and luminosity.

Absolute Magnitude: The brightness a star would have at a distance of ten parsecs (10 pc) or 32.6 ly. Continue reading “Absolute Magnitude Luminates Absolutely”

Blue and Green with Envy

In this week’s discussion topic, I attempt to answer the question “Why are Uranus and Neptune distinctly bluer than Jupiter and Saturn?”

On Uranus and Neptune, the methane absorbs red, orange and yellow light, reflecting back the blue.  In contrast, Jupiter and Saturn have only minor trace amounts of methane and quite a bit more hydrogen and ammonia.

This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Even at this extreme angle, Uranus retains the pale blue-green color seen by ground-based astronomers and recorded by Voyager during its historic encounter. This color results from the presence of methane in Uranus’ atmosphere; the gas absorbs red wavelengths of light, leaving the predominant hue seen here. Image Credit: NASA/JPL

Continue reading “Blue and Green with Envy”

Dark Seas and Bright Highlands

On the basis of lunar rocks brought back by the astronauts, explain why the maria are dark-colored, but the lunar highlands are light-colored?

Regions of both the near side and far side of the Moon not covered by mare basalt are called highlands. The highlands consist of the ancient lunar surface rock, anorthosite, and materials thrown out during the creation of the impact basins. (“Lunar Rocks | National Air and Space Museum,” n.d.)

The anorthosite rock highlands are brighter than the maria basalts.  Pulverized by meteoric action, both the basalts of the maria and the anorthosite of the highlands are covered by a blanket of powdered rock, also known as regolith. Continue reading “Dark Seas and Bright Highlands”

Gas Giant Genesis

Which giant planet formed first?

Short answer:  Jupiter

Long answer:  Still Jupiter, but let’s dive in and take a more detailed look.

Image Credit: NASA

Birth of a Gas Giant

A long time ago in a solar system very near you, just 1 or 2 AU past the snow line, enough surrounding planetesimals were accreted to become an Earth-like body containing about ten (10) Earth masses of metal and rock.  This, in turn, gave this massive body enough gravitational attraction to pull vast amounts of hydrogen, helium and ices near its orbit, creating the first planet in our solar system: Jupiter.  Impacts from the infalling gases and ices heated Jupiter up, so much so that for a short time, it outshown the protosun, if viewed from equal distances.  Jupiter lacked the total mass to become a star, needing to be seventy-five (75) times more massive to achieve the necessary compression and heat in its core to sustain fusion.

Continue reading “Gas Giant Genesis”