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Astronomical Event: January 2018’s Super Blue Blood Moon

Josa, January 29, 2018,Weather Features, Heavenly spectacle There’s a huge difference between the two episodes of the moon – “apogee“, wherein it is seen a bit farther as visible to the naked eye and a “perigee”, wherein it seems a lot bigger to us observers. Earlier this January, we observed the moon’s apogee phase. By the end of the month, many of us across the globe will yet again bear witness in anticipation of a grand lunar spectacle, a super moon, otherwise known as the blue moon. It refers to two (2) full moons in a single calendar month. This coincides with a total lunar eclipse in reference to the full moon lining up with the Earth and the Sun, according to the National Aeronautics and Space Administration (NASA).

Additionally, NASA stated that for a total lunar eclipse to happen, the moon must be full, which means it is directly opposite to the sun, with the Earth in between. The eclipse happens when the moon moves into the shadow cast by the sun shining on Earth. An eclipse does not happen every month because the moon is usually above or below the shadow (See Figure 1).

Fig-1. According to NASA, when Earth passes directly between the sun and the moon, a lunar eclipse takes place. Image Courtesy: NASA

Fig-1. According to NASA, when Earth passes directly between the sun and the moon, a lunar eclipse takes place. Image Courtesy: NASA

perigee episode will make the moon appear 14 percent larger to the observer and 30 percent brighter and closer to the horizon. As for the blue moon, this is often misconstrued as infrequent lunar event. However, this is being debunked as a myth based on NASA data, because apparently it recurs every 2.5 years.

Blood moon

According to a Forbes report, a super blue blood moon, as termed by NASA was nicknamed for the reddish hue cast on the moon. The term blood moon refers to a total lunar eclipse where a full moon lines up with the Earth and Sun. In this configuration, the Earth blocks out the Suns’s light, turning the moon from a white glowing orb to a deep red orb (See Figures 2 and 3). There will be two (2) significant events happening on the 30th and 31st of January 2018. First, the perigee moon will be at closest to the Earth by 358,995 km. Second, the Earth-Sun distance is about 149,785,000 km while the moon is at 384,835 km apart from the surface of the Earth.

2

Fig-2. The ‘blood moon’ magnificently shot in Norway by professional Norwegian Landscape & Nature Photographer Christian Hoiberg. See more on his entry at http://www.choiberg.com/blog/blood-moon-total-lunar-eclipse

3

Fig-3. Stacked up together. ‘Blood moon’ taken on September 15, 2015 showcasing the total lunar eclipse in Norway by professional Norwegian Landscape & Nature Photographer Christian Hoiberg. See more on his entry at http://www.choiberg.com/blog/blood-moon-total-lunar-eclipse

Affecting the tides

Some of us may wonder what are the direct effects of these moon phases to the Earth. Apparently, they have an effect on the oceans’ tides, all because of gravity (See Figure 4). This is confirmed by Sir Isaac Newton in 1687, wherein he explained that ocean tides result from the gravitational attraction of the sun and moon on the oceans of the Earth (Sumich, J.L., 1996).

Fig-4. Gravity and Inertia act in opposition on the Earth’s oceans, creating tidal bulges on opposite sites of the planet. On the “near” side of the Earth (the side facing the moon), the gravitational force of the moon pulls the ocean’s waters toward it, creating one bulge. On the far side of the Earth, inertia dominates, creating a second bulge. Image Courtesy: NOAA

Fig-4. Gravity and Inertia act in opposition on the Earth’s oceans, creating tidal bulges on opposite sites of the planet. On the “near” side of the Earth (the side facing the moon), the gravitational force of the moon pulls the ocean’s waters toward it, creating one bulge. On the far side of the Earth, inertia dominates, creating a second bulge. Image Courtesy: NOAA

To know how much the moon affects the tidal behavior of the Earth, let us look further into the mass involved with the Sun. It is 27,000,000 times larger than that of the moon, but it is 390 times farther away from the surface of the Earth. This means the moon has 46 percent reduction of the tide-generating force. This is twice the tide producing force versus the sun. This makes the moon the most dominant force affecting tidal action on our planet.

The moon has four (4) phases – the new moon, first quarter, full moon, and the last quarter. Also worthy to mention are the several factors affecting the tides on the Earth. These are drawn by accelerating or retarding influences of hydraulic, hydrodynamic, hydrographic, and topographic origin – and may further by modified by meteorological conditions such as wind and pressure.

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By: Adonis S. Manzan

References:

 https://weatherph.org/january-2018s-astronomical-event-lunar-apogee/

https://www.nasa.gov/topics/solarsystem/features/watchtheskies/ask-an-astronomer-about-the-shortest-lunar-eclipse-of-the-century-on-april-4.html

 https://www.nasa.gov/audience/forstudents/k-4/stories/lunar-eclipse-diagram

https://oceanservice.noaa.gov

https://www.forbes.com/sites/trevornace/2018/01/02/supermoon-blue-moon-total-lunar-eclipse-night/#2a0e72cb45b2

http://www.choiberg.com/blog/blood-moon-total-lunar-eclipse

 

Source: https://weatherph.org

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