Toshi Hirabayashi, Georgia Institute of Technology and Yaeji Kim, University of Maryland

The NASA project NEOWISE, which has given astronomers a detailed view of near-Earth objects – some of which could strike the Earth – ended its mission and burned on reentering the atmosphere after over a decade.

On a clear night, the sky is full of bright objects – from stars, large planets and galaxies to tiny asteroids flying near Earth. These asteroids are commonly known as near-Earth objects, and they come in a wide variety of sizes. Some are tens of kilometers across or larger, while others are only tens of meters or smaller.

On occasion, near-Earth objects smash into Earth at a high speed – roughly 10 miles per second (16 kilometers per second) or faster. That’s about 15 times as fast as a rifle’s muzzle speed. An impact at that speed can easily damage the planet’s surface and anything on it.

Impacts from large near-Earth objects are generally rare over a typical human lifetime. But they’re more frequent on a geological timescale of millions to billions of years. The best example may be a 6-mile-wide (10-kilometer-wide) asteroid that crashed into Earth, killed the dinosaurs and created Chicxulub crater about 65 million years ago.

Smaller impacts are very common on Earth, as there are more small near-Earth objects. An international community effort called planetary defense protects humans from these space intruders by cataloging and monitoring as many near-Earth objects as possible, including those closely approaching Earth. Researchers call the near-Earth objects that could collide with the surface potentially hazardous objects.

NASA began its NEOWISE mission in December 2013. This mission’s primary focus was to use the space telescope from the Wide-field Infrared Survey Explorer to closely detect and characterize near-Earth objects such as asteroids and comets.

NEOWISE contributed to planetary defense efforts with its research to catalog near-Earth objects. Over the past decade, it helped planetary defenders like us and our colleagues study near-Earth objects.

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Detecting near-Earth objects

NEOWISE was a game-changing mission, as it revolutionized how to survey near-Earth objects.

The NEOWISE mission continued to use the spacecraft from NASA’s WISE mission, which ran from late 2009 to 2011 and conducted an all-sky infrared survey to detect not only near-Earth objects but also distant objects such as galaxies.

The spacecraft orbited Earth from north to south, passing over the poles, and it was in a Sun-synchronous orbit, where it could see the Sun in the same direction over time. This position allowed it to scan all of the sky efficiently.

The spacecraft could survey astronomical and planetary objects by detecting the signatures they emitted in the mid-infrared range.

Humans’ eyes can sense visible light, which is electromagnetic radiation between 400 and 700 nanometers. When we look at stars in the sky with the naked eye, we see their visible light components.

However, mid-infrared light contains waves between 3 and 30 micrometers and is invisible to human eyes.

When heated, an object stores that heat as thermal energy. Unless the object is thermally insulated, it releases that energy continuously as electromagnetic energy, in the mid-infrared range.

This process, known as thermal emission, happens to near-Earth objects after the Sun heats them up. The smaller an asteroid, the fainter its thermal emission. The NEOWISE spacecraft could sense thermal emissions from near-Earth objects at a high level of sensitivity – meaning it could detect small asteroids.

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But asteroids aren’t the only objects that emit heat. The spacecraft’s sensors could pick up heat emissions from other sources too – including the spacecraft itself.

To make sure heat from the spacecraft wasn’t hindering the search, the WISE/NEOWISE spacecraft was designed so that it could actively cool itself using then-state-of-the-art solid hydrogen cryogenic cooling systems.

Operation phases

Since the spacecraft’s equipment needed to be very sensitive to detect faraway objects for WISE, it used solid hydrogen, which is extremely cold, to cool itself down and avoid any noise that could mess with the instruments’ sensitivity. Eventually the coolant ran out, but not until WISE had successfully completed its science goals.

During the cryogenic phase when it was actively cooling itself, the spacecraft operated at a temperature of about -447 degrees Fahrenheit (-266 degrees Celsius), slightly higher than the universe’s temperature, which is about -454 degrees Fahrenheit (-270 degrees Celsius).

The cryogenic phase lasted from 2009 to 2011, until the spacecraft went into hibernation in 2011.

Following the hibernation period, NASA decided to reactivate the WISE spacecraft under the NEOWISE mission, with a more specialized focus on detecting near-Earth objects, which was still feasible even without the cryogenic cooling.

During this reactivation phase, the detectors didn’t need to be quite as sensitive, nor the spacecraft kept as cold as it was during the cryogenic cooling phase, since near-Earth objects are closer than WISE’s faraway targets.

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The consequence of losing the active cooling was that two long-wave detectors out of the four on board became so hot that they could no longer function, limiting the craft’s capability.

Nevertheless, NEOWISE used its two operational detectors to continuously monitor both previously and newly detected near-Earth objects in detail.

NEOWISE’s legacy

As of February 2024, NEOWISE had taken more than 1.5 million infrared measurements of about 44,000 different objects in the solar system. These included about 1,600 discoveries of near-Earth objects. NEOWISE also provided detailed size estimates for more than 1,800 near-Earth objects.

Despite the mission’s contributions to science and planetary defense, it was decommissioned in August 2024. The spacecraft eventually started to fall toward Earth’s surface, until it reentered Earth’s atmosphere and burned up on Nov. 1, 2024.

NEOWISE’s contributions to hunting near-Earth objects gave scientists much deeper insights into the asteroids around Earth. It also gave scientists a better idea of what challenges they’ll need to overcome to detect faint objects.

So, did NEOWISE find all the near-Earth objects? The answer is no. Most scientists still believe that there are far more near-Earth objects out there that still need to be identified, particularly smaller ones.

To carry on NEOWISE’s legacy, NASA is planning a mission called NEO Surveyor. NEO Surveyor will be a next-generation space telescope that can study small near-Earth asteroids in more detail, mainly to contribute to NASA’s planetary defense efforts. It will identify hundreds of thousands of near-Earth objects that are as small as about 33 feet (10 meters) across. The spacecraft’s launch is scheduled for 2027.

Toshi Hirabayashi, Associate Professor of Aerospace Engineering, Georgia Institute of Technology and Yaeji Kim, Postdoctoral Associate in Astronomy, University of Maryland

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This article is republished from The Conversation under a Creative Commons license. Read the original article.

The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to illuminate the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/

In recent weeks, New Jersey has found itself at the center of a perplexing enigma—mysterious drones hovering in the night sky over various towns, stirring intrigue and concern among locals and officials alike. Reports of these unidentified flying objects (UFOs) have raised questions regarding their origins, purposes, and safety implications, prompting both state and federal investigations.

Eyewitness Accounts: What Are Residents Seeing?

Reports of these nighttime sightings began surfacing in mid-November. Many residents described seeing groups of drones flying in organized patterns, often noted for their unusual size—some likening them to “SUV-size drones.” Notably, sightings have occurred near sensitive areas such as Picatinny Arsenal, a U.S. military research facility, and even over Donald Trump’s golf course in Bedminster. The objects have also been documented flying over coastal regions, creating a sense of unrest among those who dwell below.

Assemblywoman Dawn Fantasia did not hold back in her fears, describing these drones as potentially 6 feet in diameter and sometimes operating with their lights off. The mystery deepens as some local lawmakers gathered with state police and officials from the Department of Homeland Security to discuss the increasing frequency of these sightings which have spanned across New Jersey and even into parts of Pennsylvania.

Official Responses: Federal and State Action

The increasing reports of drone activity have prompted cautious responses from state and federal officials. The New Jersey State Police, alongside the Federal Aviation Administration (FAA) and the FBI, have started to investigate. These agencies are eager to understand the nature of these unidentified flying objects and urge residents to report any suspicious activity.

White House National Security spokesman John Kirby recently stated that a review of the reported sightings has determined that many of these instances may actually involve manned aircraft operating legally. He affirmed that there has been no evidence of foreign involvement or threats to public safety linked to these sightings thus far.

However, not everyone is at ease. Senator Richard Blumenthal from Connecticut has gone so far as to suggest that unidentified drones spotted over sensitive areas should be shot down. At the same time, apprehensions voiced by New Jersey Governor Phil Murphy echo a collective desire for clarity. Murphy stated, “This is something we’re taking deadly seriously,” emphasizing the need for transparency and prompt actions from federal authorities.

Investigative Challenges: Identifying the Objects

The investigation into these drone sightings faces significant hurdles. Many reports may stem from harmless, legal manned aircraft, according to preliminary assessments. Yet, the mix of anxiety and curiosity has led to calls for stricter regulations on drone flights. Some lawmakers have proposed immediate restrictions, while constituents express frustration at the apparent lack of answers regarding their safety.

Local residents are also contemplating taking matters into their own hands, threatening to shoot down the drones if the government doesn’t provide clarity and action. Such self-directed responses highlight the rising tensions and concerns over privacy and safety.

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What Next? Community and Government Collaboration

As the investigation unfolds, collaboration between community members and officials remains crucial. The FBI has urged residents to share any videos, photographs, or information regarding the drone sightings. Local officials emphasize that vigilance from the public can aid in piecing together the mystery.

In the meantime, experts in drone technology maintain that many of the sightings could indicate unauthorized drone operation, necessitating clearer laws governing drone usage. The law regulating aircraft does not empower police to intervene effectively; hence, an increasing number of legislators are advocating for an examination and potential amendment of existing laws.

While the origin and purpose of these drones remain unsolved, the experience resonates with the broader conversation around drone technology, personal privacy, and safety in increasingly crowded skies. Local communities eagerly await answers, hoping that soon we can demystify what lurks above in our endless night sky.

Conclusion

The mystery of the drones over New Jersey reflects the intersection of technology, safety, and public concern in today’s society. With investigations still ongoing and community engagement essential, residents and officials alike are hoping for clarity as they navigate this aerial enigma together. In an age where the skies are becoming more crowded, understanding the nature and purpose of these flying machines will be paramount for ensuring both safety and peace of mind.

Related links:

https://apnews.com/article/fbi-drones-new-jersey-0f4aba00748ac464d42270fbe7457733

https://www.cbsnews.com/news/drones-new-jersey-what-we-know

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Beatriz Villarroel, Stockholm University

There has been increased interest in unidentified flying objects (UFOs) ever since the Pentagon’s 2021 report revealed what appears to be anomalous objects in US airspace, dubbed unidentified aerial phenomena (UAP). Fast forward to 2023, and Nasa has already formed a panel to investigate the reports and appointed a director for UAP research.

A newly founded Pentagon desk has also released footage of mysterious metallic orbs. What is perhaps most remarkable is that David Grusch, a former intelligence officer, testified under oath before the US Congress, stating that he had interviewed around 40 people involved in secret programmes dealing with crashed UFOs.

I am interested in searching the sky for alien, physical objects which may one day tell us whether we are alone in the galaxy. Consider this: within our own Milky Way galaxy, there are 40 billion Earth-sized, potentially habitable planets.

Human ingenuity has enabled us to engineer and launch probes like Voyager and Pioneer, capable of reaching the closest stars. We’ve initiated efforts such as the Breakthrough Starshot programme which aims to reach nearby star Alpha Centauri in just a few decades by exploring innovative propulsion methods. Sending a probe may be more economical than sending out radio or laser communication if there is no need to hurry.

If humans can send a probe to another star, why couldn’t another civilisation send a probe to our Solar System? Such a probe could make it to the main asteroid belt and lurk on an asteroid.

Or, it could make its way to the Earth, entering our atmosphere. If observed, it would be branded as a “UFO”. A civilisation capable of producing and sending probes could dispatch millions of them on exploratory missions throughout our galaxy.

Some may argue that such probes could only exist if they adhere to the laws of physics and engineering as we understand them today. However, humanity is a relatively young civilisation, and our knowledge is constantly evolving.

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While humans have dreamt of flying for millennia as we gazed at the skies, it has only been 120 years since the Wright brothers achieved the first powered flight. That’s about as long ago as Albert Einstein published his theory of special relativity.

Is it really so difficult to imagine that a civilisation that is hundreds of thousands years older than ours might have learned more about the laws of physics or developed a few more engineering tricks?

If a civilisation were to evolve into artificial intelligence (AI), it might survive for millions of years. This could mean it would casually regard slow to a neighbouring star as nothing more than a leisurely stroll.

That said, few astronomers felt impressed by the US Navy videos or government reports. We need significantly better evidence and data than what has been presented so far.

Unveiling UFOs

How can we test whether there are extra terrestrial probes near Earth, and whether they can be tied to the possible UFO phenomenon? There are many options. Analysing materials from potentially crashed UFOs could give irrefutable proof. This would require state-of-the-art techniques to determine if these wrecks exhibit exotic or distinctly different characteristics of manufacture.

Obtaining such exotic samples, if they indeed exist, may prove challenging – they are rumoured to be in the hands of private companies. But newly proposed legislation might offer a solution to that problem in United States by mandating that all artificial materials from any non-human intelligence be surrendered to the US government.

In the projects I lead, we are searching for artificial non-human objects by looking for short light flashes in the night sky. Short flashes typically occur when a flat, highly reflective surface — such as a mirror or glass — reflects sunlight. It could, however, also result from an artificial object emitting its own internal light.

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Such short light flashes sometimes repeat and follow a straight line as the object tumbles in space during its orbit around the Earth. This is why satellites often appear as repeating light flashes in images.

Historical photographic plates taken before the launch of Sputnik 1 in 1957 have revealed the presence of nine light sources (transients) that appear and vanish within an hour in a small image, defying astronomical explanations. In some cases, the transient light sources are even aligned, just like when short flashes come from moving objects.

The most recent finding of this kind shows three bright stars in an image dated July 19, 1952 (coincidentally, the same time as the famous Washington UFO flyovers). The three stars were never seen again.

Searching for alien probes in the modern night sky presents a serious but necessary challenge. A new research programme, known as ExoProbe, searches for short light flashes from potential alien objects with the help of multiple telescopes.

To verify the authenticity of each flash, it must be observed in at least two different telescopes. Since these telescopes are separated by hundreds of kilometres, any light flash caused by an object within the inner Solar System enables the measurement of parallax — the apparent shift in the position of an object as seen from two different points — and the calculation of the distance to the object.

The ExoProbe project also uses its own methods to filter out light flashes from the millions of space debris fragments and thousands of satellites cluttering the sky. By adding a telescope taking real-time spectra (the wavelength distributions of the light) of the objects in a wide field, you can analyse the transients before they vanish into nothingness.

Finally, increasing the number of telescopes further enhances accuracy in measuring parallax and determining the actual three dimensional location of the object. Ultimately, the goal is to identify any potential alien object and bring it back to Earth for further study.

Some 60 years of searches for extraterrestrial civilisations in the radio frequencies have yielded no candidates whatsoever. We find ourselves at a moment in time when new paths must be explored. That means we can finally focus our attention closer to home. Regardless of the outcome, this journey is certainly an homage to our insatiable curiosity.

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Beatriz Villarroel, Assistant professor of Physics, Stockholm University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The science section of our news blog STM Daily News provides readers with captivating and up-to-date information on the latest scientific discoveries, breakthroughs, and innovations across various fields. We offer engaging and accessible content, ensuring that readers with different levels of scientific knowledge can stay informed. Whether it’s exploring advancements in medicine, astronomy, technology, or environmental sciences, our science section strives to shed light on the intriguing world of scientific exploration and its profound impact on our daily lives. From thought-provoking articles to informative interviews with experts in the field, STM Daily News Science offers a harmonious blend of factual reporting, analysis, and exploration, making it a go-to source for science enthusiasts and curious minds alike. https://stmdailynews.com/category/science/