The far side of the moon is an attractive place to carry out astronomy. Credit: NASA / Ernie Wright
Lunar exploration is undergoing a renaissance. Dozens of missions, organized by multiple space agencies—and increasingly by commercial companies—are set to visit the moon by the end of this decade. Most of these will involve small robotic spacecraft, but NASA’s ambitious Artemis program, aims to return humans to the lunar surface by the middle of the decade.
There are various reasons for all this activity, including geopolitical posturing and the search for lunar resources, such as water-ice at the lunar poles, which can be extracted and turned into hydrogen and oxygen propellant for rockets. However, science is also sure to be a major beneficiary.
The moon still has much to tell us about the origin and evolution of the solar system. It also has scientific value as a platform for observational astronomy.
The potential role for astronomy of Earth’s natural satellite was discussed at a Royal Society meeting earlier this year. The meeting itself had, in part, been sparked by the enhanced access to the lunar surface now in prospect.
Far side benefits
Several types of astronomy would benefit. The most obvious is radio astronomy, which can be conducted from the side of the moon that always faces away from Earth—the far side.
The lunar far side is permanently shielded from the radio signals generated by humans on Earth. During the lunar night, it is also protected from the Sun. These characteristics make it probably the most “radio-quiet” location in the whole solar system as no other planet or moon has a side that permanently faces away from the Earth. It is therefore ideally suited for radio astronomy.
Radio waves are a form of electromagnetic energy—as are, for example, infrared, ultraviolet and visible-light waves. They are defined by having different wavelengths in the electromagnetic spectrum.
Radio waves with wavelengths longer than about 15m are blocked by Earth’s ionoshere. But radio waves at these wavelengths reach the moon’s surface unimpeded. For astronomy, this is the last unexplored region of the electromagnetic spectrum, and it is best studied from the lunar far side.
Artist’s conception of the LuSEE-Night radio astronomy experiment on the moon. Credit: Nasa/Tricia Talbert
Observations of the cosmos at these wavelengths come under the umbrella of “low frequency radio astronomy.” These wavelengths are uniquely able to probe the structure of the early universe, especially the cosmic “dark ages“—an era before the first galaxies formed.
At that time, most of the matter in the universe, excluding the mysterious dark matter, was in the form of neutral hydrogen atoms. These emit and absorb radiation with a characteristic wavelength of 21cm. Radio astronomers have been using this property to study hydrogen clouds in our own galaxy—the Milky Way—since the 1950s.
Because the universe is constantly expanding, the 21cm signal generated by hydrogen in the early universe has been shifted to much longer wavelengths. As a result, hydrogen from the cosmic “dark ages” will appear to us with wavelengths greater than 10m. The lunar far side may be the only place where we can study this.
The astronomer Jack Burns provided a good summary of the relevant science background at the recent Royal Society meeting, calling the far side of the moon a “pristine, quiet platform to conduct low radio frequency observations of the early Universe’s Dark Ages, as well as space weather and magnetospheres associated with habitable exoplanets.”
Signals from other stars
As Burns says, another potential application of far side radio astronomy is trying to detect radio waves from charged particles trapped by magnetic fields—magnetospheres—of planets orbiting other stars.
This would help to assess how capable these exoplanets are of hosting life. Radio waves from exoplanet magnetospheres would probably have wavelengths greater than 100m, so they would require a radio-quiet environment in space. Again, the far side of the moon will be the best location.
A similar argument can be made for attempts to detect signals from intelligent aliens. And, by opening up an unexplored part of the radio spectrum, there is also the possibility of making serendipitous discoveries of new phenomena.
We should get an indication of the potential of these observations when NASA’s LuSEE-Night mission lands on the lunar far side in 2025 or 2026.
Permanently shadowed craters at the lunar poles could eventually host infrared telescopes. Credit: LROC / ASU / NASA
Crater depths
The moon also offers opportunities for other types of astronomy as well. Astronomers have lots of experience with optical and infrared telescopes operating in free space, such as the Hubble telescope and JWST. However, the stability of the lunar surface may confer advantages for these types of instrument.
Moreover, there are craters at the lunar poles that receive no sunlight. Telescopes that observe the universe at infrared wavelengths are very sensitive to heat and therefore have to operate at low temperatures. JWST, for example, needs a huge sunshield to protect it from the sun’s rays. On the moon, a natural crater rim could provide this shielding for free.
The cold, stable environment of permanently shadowed craters may also have advantages for the next generation of instruments to detect gravitational waves—”ripples” in space-time caused by processes such as exploding stars and colliding black holes.
Moreover, for billions of years the moon has been bombarded by charged particles from the sun—solar wind—and galactic cosmic rays. The lunar surface may contain a rich record of these processes. Studying them could yield insights into the evolution of both the Sun and the Milky Way.
For all these reasons, astronomy stands to benefit from the current renaissance in lunar exploration. In particular, astronomy is likely to benefit from the infrastructure built up on the moon as lunar exploration proceeds. This will include both transportation infrastructure—rockets, landers and other vehicles—to access the surface, as well as humans and robots on-site to construct and maintain astronomical instruments.
But there is also a tension here: human activities on the lunar far side may create unwanted radio interference, and plans to extract water-ice from shadowed craters might make it difficult for those same craters to be used for astronomy. As my colleagues and I recently argued, we will need to ensure that lunar locations that are uniquely valuable for astronomy are protected in this new age of lunar exploration.
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Building telescopes on the moon could transform astronomy, and it’s becoming an achievable goal (2023, April 19)
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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.
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.
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.”
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.
