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The moon is coming down to Earth… eventually – Coast Reporter

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The current drought for planetary observing continues with everything but Mars either too close to the sun or the horizon. So, this month’s topic will be some esoteric facts about our moon.

• Last quarter April 4 at 03:02

• New moon April 11 at 19:30

• Close approach to Mars April 16 at 23:00

• First quarter April 19 at 23:59

• Full moon April 26 at 20:31, perigee early April 27, large tides

The current prevailing theory of the moon’s origin is that early Earth was struck by a Mars-sized body about half the diameter of the proto-Earth and about one-tenth its mass.  A glancing blow would likely leave a debris field in orbit around Earth, which would have accreted to form what is now our satellite. This hypothesis would help explain the 23-1/2 degree tilt of Earth’s axis and our resultant seasons.

The ratio of oxygen isotopes in lunar samples is essentially identical to terrestrial rocks, which suggests the moon formed from Earth’s post-impact debris field. 

Although the moon is now about 385,000 km (240,000 miles) from Earth, it formed much closer to Earth and slowly moved farther away. This was due to the tidal interactions between Earth and moon, which cause both to bulge towards the other.  While the ocean clearly rises and falls depending on the moon’s location, Earth itself does too, although to a lesser extent. Earth’s rotation tends to carry this bulge with it, with the result that the bulge, being slightly closer to the moon, adds a slight forward component to the attraction of Earth’s gravity. This slightly pulls the moon in the same direction as Earth’s rotation, slowly pulling the moon into a higher orbit while at the same time slightly slowing down the Earth’s rotation – a transfer of angular momentum from Earth to moon. 

The moon’s orbital radius is increasing by about 38 mm (about an inch and a half) per year, meaning that when Neil and Buzz walked around up there the moon was about their average height closer to the Earth.

The same thing happened to the moon: whatever rotation it had was slowed by the force of Earth’s gravity on its tidal bulge, so that it is now tidally locked to Earth and its rotational period equals its orbital period. 

Eventually, Earth’s rotation will slow until it, too, is locked to the moon’s orbital period.  At this point, Earth will still be rotating faster than it orbits the sun and the smaller tidal bulge due to the sun’s gravity will continue to slow Earth’s rotation.

Earth’s tidal bulge will then begin to lag the moon’s orbital motion, the pull will be acting in reverse and the moon will slowly start to spiral back towards the Earth.

The moon will move ever closer until it reaches 18,470 km (11,470 miles) above the Earth, a point known as the Roche limit. This is the radius inside which the tidal forces pulling objects apart exceed their mutual attraction due to gravity. 

Fragmented Moon

Ultimately, our moon will begin to fragment and we’ll have a ring like Saturn.

This forecast of Earth – moon orbital interactions was a couple of lectures in a fascinating Astrophysics course I took about 50 years ago. I can’t remember whether this would occur before or after the Sun turns into a red giant and fries us in about five billion years from now but I think I’m safe in saying that at my age I don’t have to worry about it.

The Royal Astronomical Society of Canada at: www.rasc.ca has a number of observing programs, among them “Explore the Moon,” one for telescope use and another for binoculars: www.rasc.ca/sites/default/files/EtM_Binoculars_V1.pdf  Either is highly recommended. 

At 7:00 p.m. on April 10, 2021, the Sunshine Coast branch will hold its monthly Zoom meeting online to present Dr. Janok P. Bhattacharya, Susan Cunningham Research Chair in Geology at the School of Earth, Environment and Society (SEES), McMaster University, Hamilton, ON, whose topic will be The Origin of Life and Martian Possibilities. Details are available at: sunshinecoastastronomy.wordpress.com

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The body of a Ugandan Olympic athlete who was set on fire by her partner is received by family

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NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.

Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.

She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.

Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.

“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.

It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.

Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.

Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.

Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.

“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.

He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.

Kenya’s high rates of violence against women have prompted marches by ordinary citizens in towns and cities this year.

Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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B.C. sets up a panel on bear deaths, will review conservation officer training

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VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.

Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”

Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.

“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.

B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.

Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.

Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.

Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.

“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”

Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”

“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.

Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.

“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.

This report by The Canadian Press was first published Sept. 9, 2024.

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