Is Mars About to Have Saturn-like Ring?

 When Earth formed some four and a half billion years ago, it initially had no moon, just as both Venus and Mercury are moonless. Not long after its formation, Earth was struck by a Mars-sized object. That collision knocked material off our young planet that quickly coalesced into the Moon. The collision caused Earth to spin quite rapidly, so fast that a day took only about 4 hours. The Moon was also much closer to Earth, less than a tenth of its current distance.

The Moon’s gravity created a large tidal force on Earth, slowing its spin a bit each year until our day is now 24 hours long. As Earth’s day lengthened, the Moon moved farther away. Good for the Moon. Had it remained that close, Earth’s gravitational tug on the Moon would pull it toward our planet. At some point before it collided with Earth, the tidal force on the Moon would have ripped it apart creating a ring of debris surrounding our planet.

Mars possesses two tiny moons. Phobos is only 14 miles across. Deimos is even smaller, a mere 8 miles. Both are likely captured asteroids.

Phobos orbits Mars from a distance of only 3,700 miles, less than half the diameter of Earth. It is the closest known moon to its planet. It’s so close, Mars’ gravity is slowly pulling it even closer. When it gets too close to Mars, the gravity of the Red Planet will rip it apart.

Phobos is already shown signs of this stress. Close-up photos by NASA probes show parallel grooves running across the entire moon. When the Mars Reconnaissance Rover first photographed Phobos and astronomers saw the grooves, they initially thought they were caused by the impact of the large meteor that created Stickney Crater. The collision was so powerful, it nearly shattered the small moon.

                         Stickney Crater and grooves on Phobos. Credit NASA and JPL.

Astronomers now realize that these grooves are caused by the gravity from Mars creating a strain on Phobos so strong it is having trouble holding itself together. Before long, in astronomical terms, perhaps a few million years, Phobos will shatter, forming a ring around Mars.

 

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NASA’s Artemis program plans to send astronauts to the Moon by the middle of this decade. But that’s not the end purpose of the Artemis program. Its ultimate goal is to land humans on Mars. To that end, NASA has constructed a simulated Mars Habitat at the Johnson Space Center in Houston. Later this year, four people will enter the simulator and be locked in for a year. This is the first of three crews to stay in the Mars habitat. These will simulate life on Mars, giving NASA valuable data for when crews leave for the Red Planet.

 

                                                   Mars Habitate Simulator. Credit NASA

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

 

This is reprinted by permission from the Oklahoman and www.Oklahoman.com.

NASA's Plan for a Permanent Lunar Colony

 If NASA’s current timeline works out, we will send astronauts to land on the Moon by 2026. One of their main tasks will be to set the foundation for a permanent lunar colony. The previous six lunar landing missions landed not far from the Moon’s equator. That isn’t the best location for the first lunar colony.

The problem is water. Water is necessary for astronauts, not only for drinking but also for oxygen and fuel. While water can be cooked out of lunar rocks, that process is slow and quite expensive. But water, or at least ice, does exist on the Moon. NASA’s Lunar Reconnaissance Orbiter (LRO) discovered it in the permanently shadowed craters at the Moon’s South Pole.

Cold Traps for Ice at Moon's South Pole. Credit NASA, KARI, Arizona State University

Deep craters there form “cold traps.” Comets and asteroids that contain water have crashed into the Moon for billions of years. Most of that water gets incorporated into the rocks or boiled away by the Moon’s 250-degree daytime temperature. But some wanders around the moon and ends up in these deep craters that never see sunlight. Over the eons, ice has accumulated in vast quantities in the cold traps there.

While NASA knew there was ice at the Moon’s South Pole, they needed detailed maps of exactly where the ice was located. That information has now been provided by South Korea Research Institute’s Danuri spacecraft. Among other instruments it carries is ShadowCam, a camera that is 200 times more sensitive than those aboard LRO. It can see even in very dark areas of the Moon in the dim light reflected by lunar mountains at the South Pole that stick up high enough to catch some sunlight in an otherwise dark region. Its images reveal the deep, dark craters where lunar ice hides from the heat of the sun.

These are prime sites for a lunar colony. Like Earth’s poles, the Moon’s South Pole receives continuous sunlight as the sun circles just above the horizon for months at a time. This allows the colony to collect solar energy for the colony located at the cold traps to provide the electricity needed to support a colony on the Moon.

The longest any Apollo astronauts stayed on the Moon in the 1970s was just under 75 hours. A permanent colony allows scientists to study the Moon for days or weeks at a time.

This will be our first step towards colonizing the Moon. Even on the hottest parts of the Moon, lava tubes, caves created by erupting volcanoes, can provide shelter. These locations will protect lunar residents from the heat of the day and -200 degree nights on the Moon. Some of these lava tubes are large enough to support whole cities.

Sooner than you might expect, the reality of people living on the Moon will catch up with science fiction.

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

 

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

 

Help SETI Find Alien Civilizations

 If you are a regular reader of this blog, you know that I often focus on the possibility of extraterrestrial life. This includes astronomers’ search for exoplanets, those that orbit other stars, with a particular focus on planets that could support life. I’ve discussed what conditions scientists believe a planet must have to support life and where, even in our own solar system, such conditions might exist.

Another aspect of this search for extraterrestrial life, known as SETI, involves actually looking for signals from other technological civilizations. Although various technologies have been tried, the most common involves searching for radio signals transmitted by other intelligent species. Since our own invention of radio technology, more than 100 years ago, we have been broadcasting our existence to the universe. SETI researchers look for possible signals broadcast by aliens.

The sheer amount of data is overwhelming. The Breakthrough Listen Initiative, just one of several SETI organizations, uses two radio telescopes, one in Australia and one in Virginia. They recently released their second round of data, a total of two petabytes of data. That’s a billion, billion bytes of data, and that’s just two years of data from only two telescopes.

              Greenbank Radio Telescope in Virginia searches for alien signals. Credit SETI Institute

The sheer quantity of data is overwhelming. So UCLA SETI astronomers are asking for your help. They started a citizen scientists program through the Zooniverse website. Zooniverse is a site where scientists request help from citizens in sorting through collected data. The site contains research projects from of study from many disciplines, ranging from art, history, language, medicine, and many scientific studies. Anyone can sign on with the Zooniverse site and pick any study that interests them.

UCLA SETI has a project titled “Are We Alone in the Universe?” Citizen scientists get a tutorial on how to evaluate the data, get some practice runs, and then get to evaluate real scientific data collected by SETI researchers. Go to https://www.zooniverse.org/, sign up, and chose this project.

But if this project doesn’t interest you, Zooniverse has hundreds of projects in many different disciplines that may interest you. Even if you don’t care to hunt for alien civilizations, the site has so many options for you to study, you can surely find some area that interests you. Look over the site and find one you like.

And, who knows, you just might be the first person to discover an alien civilization.

Too Much of a Good Thing?

 Away from our city lights, the night skies over our planet glisten with thousands of stars. Those we can see with our eyes are only the tip of a nearly infinite stellar iceberg. While the starry night sky provides us with breathtaking beauty, astronomers with their telescopes study much more. They examine the stars, the galaxies that stars reside in, and the space between galaxies. They use these telescopes to peer billions of years back in time, all looking for clues to how the universe works, where it came from, how it’s changing, how we came to be.

Occasionally when you share in the beauty of our night sky, you might see a “star” moving among all the others. These artificial satellites, the biggest of which is currently the International Space Station, might even elicit some level of excitement.

But, imagine you’re an astronomer studying a distant galaxy, looking for clues to how the universe came to be when one of these satellites slides across the view of your telescope disrupting the precious data your instruments are taking. That would be a big nuisance to that astronomer’s studies.

You might think, hey, it’s one little blip and there are so few, what harm can they do? But, for every satellite you notice at night, there are many more that you can’t see but which can interfere with astronomical data.

SpaceX, a private space launch company, uses its Falcon 9 rocket to launch satellites for private communications companies to orbit. One of its biggest customers, Starlink, uses thousands of satellites to provide internet access around the world. Each Falcon 9 can launch 50 or more Starlink satellites. It’s certainly a fascinating sight to watch this train of satellites traveling across your night sky as they slowly separate and move to their individual orbits. Such satellite trains initially led to many UFO reports, although the sight is common enough that they rarely generate such reports anymore. Once in their final orbit, they shine so faintly that the human eye can barely discern them.

But astronomical telescopes easily spy them. And they are more than just a nuisance. They produce bright trails on images taken by those telescopes. They can block out a star of particular interest or cause brief, transient phenomena, like the poorly understood gamma-ray bursts, to be totally missed.

Satellite tracks in an image from Cerro Tololo Inter-American Observatory in Chile 

Credit CTIO-NOIRLab-NSF-AURA

Recently, Amazon’s Blue Origin launched the first of one hundred, Blue Walker satellites. It is the largest commercial satellite ever launched, roughly half the size of a tennis court, and it rivals the brightest stars in the night sky. The fully operational Blue Walker satellites may be even larger and brighter.

I remember as a child how exciting it was to glimpse the rare satellites moving across my night sky. But for astronomers trying to understand the workings of our universe, these are becoming much more than an annoyance. All too often, they cause the loss of rare, often irretrievable astronomical data.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and Oklahoman.com.

Largest Ever Marsquake Detected by Mars Insight Lander

 Last May, the Mars Insight lander measured the strongest marsquake ever recorded at magnitude 4.7. That doesn’t seem like much. Many states in the US, especially along the west coast and Alaska, have recorded much stronger earthquakes. Even here in Oklahoma, we've had quakes within the past few years above stronger than that. Most Oklahoma quakes are linked to fracking operations. On Mars, they occur from slippage at buried faults.

An international team of researchers led by Taichi Kawamura at the Institut de physique du globe de Paris, France published a recent analysis of the May quake. In the paper, he stated, “The [May 4, 2022 quake] was definitely the biggest marsquake that we have seen.”

The data allowed scientists to learn details about the Martian interior that was unknown before that quake. For example, the shaking lasted for ten hours. The previous record holder only shook the ground for an hour.

One of the study’s co-author, seismologist John Clinton at the Swiss Seismological Service, ETH Zurich, said “The energy released by this single marsquake is equivalent to the cumulative energy from all other marsquakes we’ve seen so far. And although the event was over 2,000 kilometers (1,200 miles) distant, the waves recorded at InSight were so large they almost saturated our seismometer. For the first time, we were able to identify surface waves, moving along the crust and upper mantle, that have traveled around the planet multiple times.”

The Mars Insight Lander, credit NASA - JPL

The kicker is that until Insight began measuring these quakes on Mars, scientists believed that the Red Planet was geologically dead. Earth is almost twice the size of Mars and scientists assumed that the Martian core had cooled so that no geologic activity could occur. Geologic activity implies molten magma below the surface, and that heat could keep any subsurface water liquid.

Mars once had oceans, lakes, and rivers. When its magnetic field collapsed, supposedly due to the core solidifying, the Martian atmosphere was blasted into space by solar radiation. On Earth, that radiation is blocked by our magnetic field. Once the air thinned out, the water evaporated and was blasted into space with the atmosphere, or froze underground. At least that was the traditional scientific belief.

This large quake adds strong proof that Mars is still quite active, something few scientists believed prior to InSight with its seismometer. As Kawamura said, “Stay tuned for more exciting stuff following this.”

Who knows what other surprises await us from Mars? Unfortunately, the InSight lander has made its final discovery. Martian dust has covered its solar cells to the point that it has no more power. “We are impressed that almost at the end of the extended mission, we had this very remarkable event,” Kawamura said. Based on the data gathered from this quake, “I would say this mission was an extraordinary success.”

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

Gold on Earth Owes Its Existence to Dwarf Galaxy Mergers

 Our Milky Way galaxy, like all large galaxies, grew by accreting many smaller galaxies billions of years ago. And, you or your spouse’s, wedding ring owe those galaxies a debt of gratitude.

When our universe first came into existence nearly 14 billion years ago, it contained only hydrogen, helium, and a trace amount of lithium. These are the three lightest and simplest elements. A glance at a periodic table shows our universe contains 92 naturally occurring elements with uranium being the heaviest. We have created another dozen or so elements in laboratories around the world. Of those 92, all of them up to iron are created inside normal stars, like our sun.

Stars form these heavier elements through a process called nuclear fusion. The incredible heat in a star’s core slams lighter elements together making heavier and heavier elements and releasing more energy into the star’s core. But making iron requires more energy than it creates. Fusion reactions almost instantly halt.

Stars like our sun die rather quietly after that point. But, stars more than ten times larger than the sun die in a spectacular supernova explosion. These events release so much energy that elements heavier than iron can form. However, supernova explosions cannot account for the amount of “jewelry store elements,” like gold and platinum, in the universe.

Recent studies revealed that collisions between two neutron stars release enough energy to create the amount of gold in the universe. Astronomers have discovered hundreds of gold-rich stars in the Milky Way. But they wanted to know when and where these stars formed. Scientists from Notre Dame and Tohoku University in Japan used a powerful supercomputer to run simulations. Their work showed these stars formed in dwarf galaxies that merged with the Milky Way some ten billion years ago. In their study, they said “The gold-rich stars (we see) today tell us the history of the Milky Way. We found most gold-rich stars are formed in dwarf galaxies over 10 billion years ago. These ancient galaxies are the building blocks of the Milky Way.”

Colliding neutron stars. Credit NSF-LIGO-Sonoma State Unioversity-A. Simonnet

Not only did these many dwarf galaxies grow our Milky Way, they also created most of the gold that exists on Earth. The universe does work in mysterious ways.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.

Did an Alien Race Signal Us?

 Astronomer Frank Drake first pointed a radio telescope toward the skies in 1960 in a deliberate search for alien signals, and SETI, the search for extraterrestrial intelligence, began. Since then, astronomers have spent many thousands of hours searching for alien signals.

In 1965, Ohio State University built the Big Ear radio telescope specifically to search for alien transmissions. On the night of August 15, 1977, astronomers ran an automated scanning program in a region of the constellation Sagittarius. At 10:16 p.m., the telescope detected a 72-second burst of radio noise in the frequency range astronomers thought the best to search for alien signals. The next morning, astronomer Jerry Ehman reviewed the computer log and noticed a signal that was 20 times stronger than the background noise. He circled that portion of the computer printout and wrote “Wow!” in the margin.

Although astronomers have repeatedly searched that area of the sky looking for a repeat of the Wow signal, it has never come again. Over the years since, astronomers hunted for any possible non-alien explanation for the signal without success. Recently, the director of the Habitable Exoplanet Hunting Project, Alberto Caballero, stated "The 'Wow!' signal is still considered the best SETI candidate radio signal.” He began a search of the region of the sky where the signal originated looking for likely candidate stars.

                                            The "Wow!" signal. Credit SETI Institute

He searched for stars similar to our sun in size, age, and brightness that might host Earth-like planets. He examined data collected by the European Space Agency’s Gaia mission which is creating a map of more than a billion stars with unparalleled precision. He found 66 candidate stars similar to our sun.

Astronomers must now examine those stars to see if any possess Earth-like planets orbiting them. This process may take a while, but if the Wow signal came from an alien race, this may be our best chance to discover another intelligent civilization. At such great distances to these stars, back-and-forth communication may be impossible. But, at least we’d know we’re not alone in the universe.

 

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. After it is published there, I post that same column to my blog page.

This is reprinted with permission from the Oklahoman and www.Oklahoman.com.