Are We Close to Finding Earth 2?

 

NASA and other space agencies have launched several missions to search for exoplanets, planets that orbit other stars. The Holy Grail of such programs is finding an Earth-like planet orbiting a sun-like star at the right distance to allow liquid water on the surface. Such planets seem to be the most likely candidates to search for life.

While astronomers have yet to find a perfect Earth 2, statistical analysis of NASA’s most successful planet hunter, the Kepler Mission, uncovered some promising data. A study by NASA scientists alongside collaborators from around the world who worked on the Kepler mission came to an exciting conclusion. According to the research, about half the stars similar in temperature to our Sun could have a rocky planet capable of supporting liquid water on its surface.

Image Caption/Credit: NASA’s Kepler Planet Finder telescope, credit NASA

"Kepler already told us there were billions of planets, but now we know a good chunk of those planets might be rocky and habitable," said the lead author Steve Bryson, a researcher at NASA's Ames Research. "Though this result is far from a final value, and water on a planet's surface is only one of many factors to support life, it's extremely exciting that we calculated these worlds are this common with such high confidence and precision."

Kepler detected planets by continuously staring at thousands of stars, watching for a tell-tale drop in brightness caused by an orbiting planet crossing in front of a star. Such a method couldn’t detect planetary systems seen more face on, so astronomers had to use statistical methods to extrapolate from the Kepler data to all the other stars in our galaxy. Kepler discovered so many exoplanets from its limited mission that astronomers now believe that more than half of the four billion stars in the Milky planet possess planets, typically more than one.

Using their most conservative estimate, that 7% of all sun-like stars have Earth-like planets, meaning some 300 million exist in our Milky Way alone. Their most likely estimate states that Earth-like planets orbit 50% of sun-like stars, making more than 2 billion Earth-like planets. Since we know of only one planet with life, ours, those planets are the best place to begin to search for alien forms of life.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

Where Did the Gold in Your Ring Come From?

 

Astronomers have a pretty good understanding of where the matter in our universe comes from. In the beginning, there was only hydrogen, helium, and a tiny smattering of lithium. Everything else, the oxygen we breathe, the carbon that makes up so much of our bodies, the silicon, magnesium, aluminum, and other elements that make up our planet, were all formed inside stars and released into the wider universe when stars explode.

Supernova Remnent Casseopeia A. Credit NASA

But there is one element that still has astronomers bumfuzzled: gold. There is too much of it. Supernova explosions can’t begin to account for the amount that we see because the gold is trapped in the neutron stars, the remnants of supernovas. Colliding neutron stars release prodigious amounts of gold, as do so-called magneto-rotational supernova. These rare supernovas spin so fast and generate such strong magnetic fields that they literally turn themselves inside out. This releases all of their trapped gold atoms. But while both produce extraordinary quantities of gold, they are extremely rare and cannot begin to account for all the gold we find here on Earth.

Chiaki Kobayashi is an astrophysicist at the University of Hertfordshire in the United Kingdom. She led the new study to determine the origin of gold. "There are two stages to this question," she said. "Number one: neutron star mergers are not enough. Number two: Even with the second source, magneto-rotational supernova, we still can't explain the observed amount of gold." Kobayashi and the other study authors accounted for the formation and relative abundance of all elements from carbon to uranium. All except for gold. Its abundance remains a mystery.

So, the next time you put on that gold ring or necklace, you can marvel that our Earth has as much gold as it does.

 

 Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

 

Any Volunteers to Be the First to Travel Through a Wormhole?

Science fiction has long imagined wormholes as a means of traversing the great distances between the stars in short, by human standard, timespans. Such literary devices allow spaceships, in essence, to cover great distances in hours or days instead of centuries that normal space travel would require. Wormholes connect two points in space in a way that the distance between them through the wormhole is much shorter than the distance between them in normal space, like taking a cosmic shortcut.

General relativity tells us that to make a wormhole requires enormous amounts of negative energy which, according to Einstein’s equations, isn’t possible. But, the other grand realm of physics, quantum mechanics, says not so fast.

In a study titled “Humanly traversable wormholes,” Juan Maldacena of the Princeton Institute of Advanced Study and Alexey Milekhin, a graduate of astrophysics student also at Princeton University, claim that we can make such wormholes. They base their calculations on the Randall-Sundrum II model, a theory that postulates a five-dimensional, warped geometry for the universe instead of the one we are familiar with that contains only normal four dimensions. Maldecena and Milekhin claim, using that theory, stable, person-sized wormholes could be created.

                                             Spaceship entering a wormhole. Credit NASA

You have to start, the researchers say, with a black hole that has a large magnetic charge. Such a special wormhole would allow spacefarers to traverse, say, 10,000 lightyears, one-tenth of the way across our galaxy, in a second. The only problem is that to the people at either end of the wormhole, that trip would appear to take 10,000 years, meaning these special wormholes really create shortcuts through time rather than space.

I bet they could still find volunteers willing to take that trip.

  

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

Martian Life, if it Exists, Could Still Be Present Underground

 

Earth sits right in the middle of our sun’s habitable zone, the region where the heat of the star allows liquid water to exist on the surface of a planet. Mars orbits at the outer edge of this zone. Astronomers generally agree that Mars once sported rivers, lakes and, oceans. Mars reached such life-supporting conditions even before Earth. Its smaller size allowed it to cool more quickly from the heat of formation.

But Mars’ smaller size also allowed its core to cool and solidify long ago, killing its magnetic field. Without that magnetic field, solar radiation slowly knocked the atmosphere of Mars into space. Lacking an atmosphere, Mars couldn’t trap the sun’s heat, so it turned cold. Nighttime temperatures routinely drop to near 100 degrees below zero.

But, prior to the loss of its atmosphere, Mars sported conditions that could have supported life. That is no longer true of the surface of Mars. The thin atmosphere can no longer warm the surface of Mars nor protect it from cosmic radiation. Many scientists, including astrophysicist and research scientist Dimitra Atri, from the Center for Space Science at NYU Abu Dhabi, believe that conditions not far below the surface could potentially support life, albeit only at the bacterial level.

In 2022, the European Space Agency and Roscosmos, the Russian space organization, will launch the ExoMars craft, which includes the Rosiland Franklin rover. Atri says that rover will have the ability to detect any such subsurface life on the Red Planet. "It is exciting to contemplate that life could survive in such a harsh environment, as few as two meters (six feet) below the surface of Mars," said Atri. "When the Rosalind Franklin rover onboard the ExoMars mission, equipped with a subsurface drill, is launched in 2022, it will be well-suited to detect extant microbial life."

                           ExoMars Rosalind Franklin rover, Credit European Space Agency (ESA).

If we find life on Mars, it will indicate that life forms easily, given that life developed on both planets in our solar system capable of supporting it. That tells astronomers that perhaps many of the tens of billions of Earth-like planets in our Milky Way galaxy likely did, too.

     Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

Can Earth-like Exoplanets Actually Support Life?

As of July 4^th, the NASA Exoplanet Archive (https://exoplanetarchive.ipac.caltech.edu/) lists 4,183 confirmed exoplanets, planets orbiting other stars, with another 2089 candidate planets awaiting confirmation. NASA and other institutions have only studied a tiny percent of all the stars in our Milky Way. Based on the sample so far, astronomers estimate that planets outnumber stars in our galaxy. That means the Milky Way contains several hundred billion planets.

These exoplanets come in a bewildering variety. Some are Jupiter-sized planets so close to their parent star that the heat from the star evaporates them. Some Earth-sized planets get so hot, they rain liquid metal from their clouds. Most confirmed planets are significantly larger than Earth, but that’s because larger planets are easier to discover than smaller planets. Astronomer estimate that Earth-sized planets number in the billions.

   Most Earth-like Exoplanets, credit NASA

Being the size of Earth doesn’t mean such a planet has life on it. Many factors play into planet habitability. Distance to its parent star determines surface temperature. Too hot or too cold and habitability becomes unlikely. The type of parent star plays a crucial role. Stars smaller than our sun often produce large, dangerous stellar flares.

If Earth is a good example of what conditions necessary for a planet to support life, water is an absolute must. On our planet, where there’s water, life exists, even at the bottom of the ocean, with near-freezing temperatures, in boiling hot springs, or three miles underground in cracks in the rock.

Scientist Lynnae Quick along with several other NASA scientists looked at the likelihood of finding other life-bearing planets. This initial study contained a small sample of only 53 Earth-sized planets. They specifically looked to see if the planets could support surface or subsurface oceans, as is the case with several moons in our own solar system. Of those, they calculated that 30 likely possess such bodies of water, more than half of the planets they analyzed. With a few billion Earth-sized planets in our galaxy alone, that means there might be a lot of life-bearing planets out there. "Forthcoming missions will give us a chance to see whether ocean moons in our solar system could support life,” said Quick.

The study didn’t address the presence of intelligent aliens. There isn’t enough data to decide that. But at least we have some idea of the possibilities now.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

You Can Help NASA as a Citizen scientist

In 2003, NASA launched a pair of twin rovers to Mars. Spirit and Opportunity landed on opposite sides of the Red Planet in early 2004. But Spirit became stuck in deep sand in 2010 while Opportunity continued functioning until 2018. Those two were followed by Curiosity, still going strong on the Martian surface. But Curiosity’s wheels became worn down early in its mission due to traveling over a field of tough, sharp rocks.

NASA's Curiosity Rover on Mars, credit NASA

Now, NASA is asking for your help in training Curiosity to recognize and avoid terrain that might cause a problem. NASA partnered with the citizen science site Zooniverse (www.zooniverse.org). Zooniverse contains dozens of projects that citizen scientists, you, can help with. I have written about Zooniverse in several past columns, but the site is constantly adding new projects at the request of scientists around the world. There are many subjects that researchers need help in ranging from Arts to Language, History, Medicine, and Physics, just to name a few. Once you register on the site, you can join in any of the projects. Some Zooniverse volunteers have made significant discoveries and are even named as collaborators on the scientific papers produced with their help.

 The project that helps Curiosity drive safely is called AI4Mars. Not only will it help Curiosity, it will also teach the next Mars rover, Perseverance, expected to launch in July. For now, Curiosity needs your help as its wheels are already compromised, and NASA doesn’t want it to meet the same fate as Spirit.

Mars Perseverance Rover set for launch in late July 2020, credit NASA

The Zooniverse website describes the AI4Mars project goal: “By participating in this project, you will help improve the rovers’ ability to identify different, sometimes dangerous, terrain - an essential skill for autonomous exploration!

 “Terrain is important to get around on Mars. Spirit got stuck in a sandpit and ended its mission after 7 years of exploring Mars. Opportunity and Curiosity also have experienced getting stuck in sand, although they were able to continue on their missions. Don’t you think it would be nice if the Mars rover could identify dangerous terrain by herself? That is what a team at NASA Jet Propulsion Laboratory is working on using Machine learning – essentially the same technology used by self-driving cars on Earth. To do so, the rover needs training data to learn from.

“We're counting on citizen scientists' help in labeling a set of images captured by Mars rovers so that we collectively create the Solar System's first public benchmark for Martian terrain classification.”

AI4Mars is only one of 96 projects on the Zooniverse site where scientists in all disciplines ask for the help of citizen scientists like yourself. If you have always liked science but thought you just weren’t cut out for it, this is where you can help real scientists do real, important science.

Each month, I write an astronomy-related column piece for the Oklahoman newspaper. On the following day, I post that same column to my blog page.

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

Walk the Entire Vertical Relief of Earth

AUTHOR’S NOTE: Since this was originally written for the Oklahoman newspaper, I used reference points in Oklahoma. So, I’ve added the distances to the streets/cities listed here so you can figure out the same for wherever you live.

Now that restrictions related to the COVID-19 pandemic have been relaxed, I imagine a lot of folks are out and about. Perhaps you are walking more, going to the park again, or even taking trips to some of our state’s great outdoor attractions.

Here’s a trip idea: walk to the top of Mt. Everest, the tallest point on Earth. Or to the bottom of the Mariana Trench, the lowest point on Earth. Think those are impossible walks? Of course, they are, but you can walk a simulation of those trips.

The summit of Mt. Everest is five and a half miles above sea level. That would be about the same as walking north along May Avenue from Reno to Grand Boulevard (5.8 miles, 9.3 km). The average person walks two to three miles per hour (3.2 – 4.8 km/hour), so such a walk would only take about two hours.

Mt. Everest Credit Benjamin Oppenheimer and USGS

The Mariana Trench is just under seven miles deep, about the same as walking south on May south from Reno to SW 104^th street (7 miles, 11.3 km), a walking trip taking less than three hours. When you get there, you can turn around and walk for five hours north all the way back to Grand, and you have walked the entire vertical relief of planet Earth. That doesn’t seem so far when you think of it like that.

        Schematic of Mt. Everest with Mariana Trench, Credit Daily Mail

How about we go even farther, to the edge of space? By general agreement, space scientists define the edge of space, what’s known as the Kármán Line, as 62 miles (100 kilometers) above sea level. I know I could not easily walk that far. And even if I could, it would take more than a day to do so.

So, let’s drive. Hop in your car and drive to Weatherford, 110 miles (177 km) west of Oklahoma City, a bit less than half-way to the Texas Border. You passed the Karman Line at Hydro and are now ten miles (16.1 km) into space. Keep driving on to Amarillo, a total of 259 miles (416.8 km), and you’ve reached the cruising altitude of the International Space Station (254 miles, 408.8 km).

Who knew that if you turned west at the Amarillo Junction (the junction of I-44 and I-40), you’d be heading to the ISS?

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.newsok.com.