After 152 years, three phenomena of total lunar eclipse will occur concurrently: super moon, blue moon and blood moon.
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Kompas/Totok Wijayanto
Staff at the Taman Ismail Marzuki planetarium in Central Jakarta set up telescopes on Tuesday (30/1) for observing the supermoon that evening.
BANDUNG, KOMPAS – After 152 years, three phenomena of total lunar eclipse will occur concurrently on Wednesday (31/1/2018): super moon, blue moon and blood moon.
The total lunar eclipse on Wednesday (31/1/2018) will occur at the same time as a super moon and can be witnessed in a number of regions across Indonesia. However, people are urged to be on the lookout for any impacts of a super moon, a blue moon and a blood moon taking place concurrently, namely in the form of high tides that can disrupt sailing and trigger tidal floods.
“The total lunar eclipse tonight will be special as three lunar eclipse phenomena will take place at the same time. This occurred the last time on March 31, 1866, or 152 years ago. These three phenomena are happening at the same time in their respective cycles,” Bandung Institute of Technology (ITB) astronomer Moedji Raharto said in Bandung on Tuesday (30/1).
The three phenomena will trigger higher tides as the Moon will be on its closest point on its orbit to Earth. The Earth and the Moon have their own gravitational pulls that they exert on each other.
“During a super moon, seawater is at its closest distance to the Moon’s center. Consequently, the Moon’s gravity will exert a stronger pull on seawater. This will pull seawater towards the Moon and create tides,” Moedji said.
The Sun, the Moon and the Earth will be on a straight line on January 30 – February 1, 2018. This rare phenomenon of a super moon will take place concurrently with a total lunar eclipse. The Moon will be on the closest point in its orbit to Earth on January 30. Due to its closer proximity, the Moon will look larger, lending it the name super moon. Meanwhile, a full moon will also occur on January 31, at the same time as the total lunar eclipse.
Meteorology, Climatology and Geophysics Agency (BMKG) chief Dwikorita Karnawati said that the lunar eclipse could be witnessed in its entirety on the Pacific Ocean as well as parts of East Asia, Indonesia, Australia and northwestern America. In Indonesia, the phenomenon is most visible between the East Java-Central Java border and western Sumatra.
Despite the phenomenon’s rarity and attractiveness, Dwikorita said that she reminded people living in coastal regions to be on the lookout of tides as high as 1.5 meters. On the other hand, the phenomenon may trigger ebbs of between one and 1.1 meter in several coastlines. Maximum tides may cause disruption in sea and coastal transportation, inland fisheries and loading and unloading activities in harbors.
BMKG information and weather forecast division head Ramlan said that high tides may occur in all coastlines in Indonesia. North Jakarta, Semarang, Surabaya, Bali, West Nusa Tenggara, East Nusa Tenggara, Makassar and Manado are among regions on alert for possible tidal floods.
BMKG researcher Siswanto said that super moon and total lunar eclipse’s influence on high tides depended on the character and daily variations of tides, which vary between coastlines. During the super moon on January 2-4, tidal floods occurred in Mamuju, Madura, Surabaya, Gorontalo and Jakarta, among other places. At the time, maximum tide in North Jakarta reached 90 centimeter.
“In this super moon, as the Moon will be at a larger distance from the Earth, the Moon’s gravitational pull on tides will be lower. North Jakarta is predicted to experience a maximum tide of 80 centimeter. Tides in other regions will also be smaller than in previous super moons,” Siswanto said.
Separately, National Institute of Aeronautics and Space (LAPAN) head Thomas Djamaluddin said that, even without a total lunar eclipse, full moons will always result in tides as the Moon’s gravitational pull will be reinforced by the Sun’s. During lunar eclipses, the effect will be stronger as the Sun, the Moon and the Earth will be in a straight line.
“The total lunar eclipse on January 31 will have a stronger impact as it happens at the same time as a super moon, when the Moon is at its closest to the Earth,” Thomas explained. However, whether or not tides will result in floods will depend on regional weather and geographical conditions. People should be on alert if maximum tide occurs at the same time as a heavy rain on land or on seas, especially in Jakarta.
Regarding this, Jakarta water resources agency said that it would be prepared to face the total lunar eclipse. Some 1,000 blue troops would be on the lookout on Jakarta’s northern coast. Agency head Teguh Hendarwan said that the agency was prepared for a worst-case scenario of high tides of up to 2.5 meters.
The blue troops, specialized officers of the city water resources agency, will be on alert for 24 hours along Jakarta’s coastline. The agency has also prepared sandbags and heavy equipment to anticipate tidal floods.
Triggering earthquakes
Thomas said that researches had shown that full moons or new moons taking place at the same time as lunar eclipse could trigger energy releases at the boundaries of the Earth’s plates which might lead to earthquakes. One example is the Aceh earthquake in 2004, which occurred during a full moon. In the morning, the moon was on the west and the waters around Aceh was on maximum ebb.
Consequently, the Indo-Australian plate on the Indian Ocean, which had been pressured by the mass of the seawater, lost that pressure during maximum ebb. This triggered the subduction of the oceanic plate under the Eurasian plate and resulted in tremors. While eclipses do not cause earthquakes, they may trigger them. “We do not know when the energy releases occur,” Thomas said.
Observation
Moedji said the three lunar eclipse phenomena served as a moment for scientists to observe the Moon’s surface. To satisfy people’s curiosity, Planet Sabuga collaborates with ITB’s astronomy department, Planet Sains, ITB Astronomy Students’ Association, ITB Astronomy Department Alumni Association and Rumah Salman ITB to hold a total lunar eclipse observation with Moedji Raharto. The event will be held in Sasana Budaya Ganesha (Sabuga) from 4 p.m. to 10 p.m. and will comprise moon observation with telescopes, eclipse-themed film screening and eclipse discussion.
In Jakarta, the Science Exhibition Center (PP Iptek) at Taman Mini Indonesia Indah (TMII) cultural park will hold a total lunar eclipse observation from 5:30 p.m. to 9 p.m. PP Iptek director M Syachrial Annas said that three telescopes would be provided at the location.
