‘City killer' asteroid on collision course with Moon could damage satellites

New observations of the 'city killer' asteroid once thought to be on a collision course with the Earth indicate it will miss the planet but strike the Moon and pose 'potential danger' to satellites.
Recent estimates of the building-sized space rock's trajectory suggest it has a 4 per cent chance of hitting the lunar surface in December 2032.
Astronomers, including from the University of Western Ontario, estimate in a new study that such an impact may release energy equivalent to 6.5 megatons of TNT and produce a lunar crater nearly 1km in diameter.
In comparison, the atomic bombing of Hiroshima by the US in 1945 produced explosive energy equivalent to nearly 0.015 megatons of TNT.
A strike from the space rock, called 2024 YR4, could generate a lunar debris cloud weighing over 100,000,000kg, according to the yet-to-be peer-reviewed study.
As much as 10 per cent of this debris could 'accrete to the Earth on timescales of a few days'. And, depending on the impact location of the asteroid on the Moon, the lunar ejecta could expose satellites to meteorites for years.
'Of primary concern are ejecta particles above the impact hazard threshold (0.1 mm) for satellites delivered directly to low Earth orbit on relatively short timescales – days to months – and that could pose a hazard to spacecraft," the study states.
The risk posed to satellites would depend on several factors, including the location of the impact, size of the lunar crater, the amount of material ejected by the collision, and the size distribution of the escaped ejecta. Of these factors, the study notes, location of the impact was the most critical.
'Because the moon is orbiting the Earth at approximately 1km per second, for ejected material to reach Earth quickly, the impacting object needs to hit the trailing edge of the moon,' it says.
The impact should also happen in a way that the ejected material's velocity 'largely cancels out the moon's orbital velocity'.
The study simulates 10,000 clones of the asteroid taking different trajectories and in 410 of them, the space rock strikes the Moon.
If the asteroid does strike the Moon, it is likely to do so in the southern hemisphere.
Analysing the 410 potential impact scenarios reveals that there is a significant probability of a 2024 YR4 strike delivering 10 per cent of the impact debris to near-Earth space, posing risks to astronauts and spacecraft.
'This will all occur during the few days of maximum ejecta delivery from a 2024 YR4 impact," researchers say.
Since the number of satellites orbiting the Earth is increasing exponentially, the debris may pose an even greater threat by 2032.
'Given the very large total exposed area for satellites by 2032,' the new study warns, 'it becomes possible that hundreds to thousands of impacts from mm-sized debris ejected by a lunar impact from 2024 YR4 will be experienced across the entire satellite fleet.'
Based on the new findings, researchers call for measures being taken to safeguard the Earth from dangerous asteroids to be extended to protect the Moon.

Try Our AI Features

Explore what Daily8 AI can do for you:

Learn with AIFact CheckingText to SpeechAI Summary

Related Articles

Scotsman

8 hours ago

• Scotsman

Here's all you need to know about the summer solstice, including when the summer solstice is this year, why the date changes and what the weather forecast is.

Watch a Met Office video explaining the summer solstice - When is the summer solstice? Sign up to our daily newsletter – Regular news stories and round-ups from around Scotland direct to your inbox Sign up Thank you for signing up! Did you know with a Digital Subscription to The Scotsman, you can get unlimited access to the website including our premium content, as well as benefiting from fewer ads, loyalty rewards and much more. Learn More Sorry, there seem to be some issues. Please try again later. Submitting... The Met Office says the summer solstice occurs when the northern hemisphere is fully tilted towards the Sun. It is the longest day and shortest night of the year. Here's all you need to know about the summer solstice, including when the summer solstice is this year, why the date changes and what the weather forecast is. Advertisement Hide Ad Advertisement Hide Ad Daniel Leal / AFP via Getty Images | Daniel Leal / AFP via Getty Images Is the summer solstice the start of summer? Meteorological summer began on June 1, and will end on August 31, as it does every year. However, the summer solstice is the start of astronomical summer, which will end on September 22 this year. When is the summer solstice? The summer solstice occurs on June 21 or June 22 each year. This year the summer solstice will be on June 21. Why does the date of the summer solstice change? According to the BBC, the exact date of the summer solstice changes slightly each year due to the calendar year not perfectly matching the time it takes for the Earth to orbit the Sun. Advertisement Hide Ad Advertisement Hide Ad Is the summer solstice the latest sunset of the year? The summer solstice is the day with the most hours of daylight in the year, but it's not the latest sunset or the earliest sunrise. The earliest sunrises take place before the summer solstice, and the latest sunsets happen after. Is the summer solstice celebrated? Many people in the UK celebrate the summer solstice at Stonehenge. Stonehenge was built to align with the sun on the solstices. This year summer solstice will be celebrated at Stonehenge from 7pm on June 20 to 8am on June 21. Advertisement Hide Ad Advertisement Hide Ad There will also be a solstice swim in Bridlington. The Flamborough Flippers are inviting people to join them for a swim in the sea, and ask people to try and be in the water at Bridlington's North Beach by 04:42 on June 21. In Scotland, Jupiter Artland in Edinburgh is running a summer solstice celebration evening, with activities such as sound baths, sunset swims and flower crown building. To find out more and to book tickets visit their website here . What is the forecast for the summer solstice? The Met Office UK weather forecast for summer solstice this year - June 21 - is: 'Hot and humid with sunny spells. Thundery showers moving north and east through the day, heaviest over northern England and Wales. Turning fresher from the west later.'

Daily Mail​

11 hours ago

• Daily Mail​

Dead NASA satellite inexplicably comes back to life to fire huge pulse that lit up the sky

A NASA satellite that had remained inactive in orbit for nearly six decades suddenly emitted a powerful radio signal, leaving astronomers around the world stunned. The brief but intense signal, detected by radio telescopes in Western Australia, lasted only a fraction of a second yet became the brightest object in the sky, momentarily outshining entire galaxies and stars. The source of this unexpected burst was Relay 2, a communications satellite launched by NASA in 1964. After both of its transmitters failed in 1967, the satellite had been silent and declared defunct until now. Experts believe the signal wasn't deliberately transmitted by the satellite, but was triggered by an external event. One possibility is an electrostatic discharge: a sudden release of electrical energy, similar to a spark, caused by the satellite building up charge as it orbits through Earth's magnetic field. Another theory is that a micrometeoroid, a tiny piece of rock traveling at high speed, struck Relay 2, causing a burst of heat and charged particles that emitted the brief but intense signal. The burst briefly emitted about 400 watts of power, similar to a small microwave oven. The fact that this signal remained that powerful after traveling from space to Earth makes it especially rare. Australian scientists, who were scanning the sky for fast radio bursts (FRBs)—short, high-energy flashes typically originating from deep space—made the startling discovery. According to NASA, FRBs can briefly outshine entire galaxies, a phenomenon that occurs in the blink of an eye. However, this signal was unique: it originated not from a distant galaxy but from within Earth's orbit, just about 2,800 miles above the planet's surface. 'We thought we might've found a new pulsar or a never-before-seen object,' Dr. Clancy James, lead researcher and associate professor at Curtin Institute of Radio Astronomy, told New Scientist. 'Instead, we saw an incredibly powerful radio pulse that eclipsed everything else in the sky for a split second.' The burst was detected by the Australian Square Kilometer Array Pathfinder (ASKAP), a network of 36 radio telescopes. Researchers quickly traced the source to Relay 2, which happened to be passing overhead at that exact moment. Despite lasting only nanoseconds, the radio burst was extraordinarily strong. Scientists estimated its strength at more than three million janskys, a unit used to measure radio wave intensity. That's roughly 100 billion times stronger than the radio signals from your typical smartphone. The shape of the signal was clean and well-defined, allowing scientists to analyze it in detail. Relay 2 was originally launched to improve satellite communication and conduct studies on Earth's radiation belts, areas filled with charged particles trapped by the planet's magnetic field. It carried two transmitters and was designed to spin for stability. But by mid-1967, both transmitters had failed, and the satellite became just another piece of space junk orbiting Earth. At first, researchers thought the detected signal came from a distant cosmic object. But a closer look confirmed it aligned exactly with Relay 2's position in the sky. 'This must have been caused by an external trigger, like an electrostatic discharge or a micrometeorite hit,' Dr. James explained. The burst lasted 1,000 times faster than previous electrostatic signals detected from satellites, which typically last a microsecond (one-millionth of a second). This makes it the fastest and most powerful signal of its kind ever recorded near Earth. While the signal caused a stir in the astronomy world, it also raised concerns. Many telescopes scan the sky for signals from far-off galaxies, and an unexpected burst from a nearby defunct satellite could cause confusion or lead to false discoveries. Still, some scientists see a silver lining. Dr Karen Aplin, a space weather expert at the University of Bristol, said this surprise detection could lead to new tools for studying electrical activity in space. 'It may ultimately offer a new technique to evaluate electrostatic discharges in orbit,' she said.

NBC News

12 hours ago

• NBC News

The summer solstice is here. What to know about the longest day of the year

Peak sunshine has arrived in the Northern Hemisphere — the summer solstice. Friday is the longest day of the year north of the equator, where the solstice marks the start of astronomical summer. It's the opposite in the Southern Hemisphere, where it is the shortest day of the year and winter will start. The word 'solstice' comes from the Latin words 'sol' for sun and 'stitium' which can mean 'pause' or 'stop.' The solstice is the end of the sun's annual march higher in the sky, when it makes its longest, highest arc. The bad news for sun lovers: It then starts retreating and days will get a little shorter every day until late December. People have marked solstices for eons with celebrations and monuments, including Stonehenge, which was designed to align with the sun's paths at the solstices. But what is happening in the heavens? Here's what to know about the Earth's orbit. Solstices are when days and nights are at their most extreme As the Earth travels around the sun, it does so at an angle relative to the sun. For most of the year, the Earth's axis is tilted either toward or away from the sun. That means the sun's warmth and light fall unequally on the northern and southern halves of the planet. The solstices mark the times during the year when this tilt is at its most extreme, and days and nights are at their most unequal. During the Northern Hemisphere's summer solstice, the upper half of the earth is tilted toward the sun, creating the longest day and shortest night of the year. This solstice falls between June 20 and 22. Meanwhile, at the winter solstice, the Northern Hemisphere is leaning away from the sun — leading to the shortest day and longest night of the year. The winter solstice falls between December 20 and 23. The equinox is when there is an equal amount of day and night During the equinox, the Earth's axis and its orbit line up so that both hemispheres get an equal amount of sunlight. The word equinox comes from two Latin words meaning equal and night. That's because on the equinox, day and night last almost the same amount of time — though one may get a few extra minutes, depending on where you are on the planet. The Northern Hemisphere's spring — or vernal — equinox can land between March 19 and 21, depending on the year. Its fall — or autumnal — equinox can land between Sept. 21 and 24. On the equator, the sun will be directly overhead at noon. Equinoxes are the only time when both the north and south poles are lit by sunshine at the same time. What's the difference between meteorological and astronomical seasons? These are just two different ways to carve up the year. While astronomical seasons depend on how the Earth moves around the sun, meteorological seasons are defined by the weather. They break down the year into three-month seasons based on annual temperature cycles. By that calendar, spring starts on March 1, summer on June 1, fall on Sept. 1 and winter on Dec. 1.