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Are We Alone In The Universe? Scientists Contemplate

This is a question that impacts not only science but theology, philosophy and other areas. It’s a curiosity. It’s part of being human.

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galaxy, universe
Hubble's view of a galaxy in Ursa Major, 65 million light-years away. VOA

The Hubble Telescope has given us spectacular pictures from space, from the dramatic image of the Pillars of Creation in the Eagle Nebula, some 6,500 to 7,000 light years from Earth, to a snapshot of nearly 10,000 galaxies, including some that may be among the most distant known, existing when the universe was just 800 million years old.

Awe-inspiring though they are, they are not detailed enough to help us in our search for life in the trillions of galaxies across the universe. And physicist Justin Crepp says the prospects for finding life out there are very good.

“If tens of a percent of stars have planets that could resemble the earth and potentially have life, then the implications are that there are billions of them just within our Milky Way Galaxy.”

Crepp, an associate professor of Physics at the University of Notre Dame, has been hard at work answering the age-old question, “Are we alone in the universe?” As a member of the National Academy of Sciences Committee on Exoplanet Science Strategy, his job is to make recommendations on how and what the U.S. will explore in space over the next decade.

In September, the committee released its initial 260-page report detailing seven recommendations. First, it encourages NASA to fly a space-based mission to directly image and characterize earth-like planets around other stars and take pictures of them. But Crepp says that’s a very challenging technical problem.

“If you try to image a planet, you run into several difficulties,” he explains. “One is that their separation is very small on the sky. So, you need to spatially resolve and isolate the signal of the planet. So, you need a certain size telescope to do that. The problem is earth’s atmosphere blurs out the images, and so it exacerbates the issue.”

Another issue is that the starlight is so bright, scientists need to find a way to block it to see the planets around it. The committee thinks the technology to do that exists, but they must be able to get above the earth’s atmosphere with the right equipment to make it happen.

 

WFIRST, universe
WFIRST, the Wide Field Infrared Survey Telescope, shown here in an artist’s rendering, will provide astronomers with Hubble-quality images of large swaths of the sky. VOA

 

Better eyes on the skies

That leads to the committee’s second recommendation, this one, for the National Science Foundation: complete work on the Giant Magellan Telescope in Chile, and start to build the proposed Thirty Meter Telescope in Hawaii. The new technology in these super telescopes will produce images 10 times sharper than those from the Hubble, even though they are ground-based.

Their highly sophisticated equipment will also allow scientists to greatly enhance the work of the third recommendation: completing the partially funded Wide Field Infrared Survey Telescope or WFIRST. When launched into space, it will search for and gather information on planets hundreds of light years away.

Crepp says that data will help scientists learn what the planets are made of.

“Is it a giant puffy atmosphere, or is it a rock or somewhere in between? Is it a water world? We don’t know the answers to these yet, but we’re just starting to get the first hints and inclinations what these worlds might be like around other stars,” Crepp said.

WFIRST, universe
Cosmic Crash with Dwarf Galaxy Reshaped Milky Way: Study. (IANS)

More importantly, scientists will try to determine if there are any signs of life.

The panel’s other recommendations include building new highly sensitive equipment, creating new ways for multidisciplinary teams all over the world to collaborate on various aspects of the project, and forming a profitable investor program to further laboratory, ground-based and theoretical telescopic research.

The big question

Crepp notes that people have wondered for millennia if our planet was unique in the universe, whether we are truly alone.

Also Read: NASA Hubble Completes First Science Operations

“This is a question that impacts not only science but theology, philosophy and other areas. It’s a curiosity. It’s part of being human. Is our world special? Is it isolated? Are there other planets out there that have life? Can we communicate with them? Are they our distant brethren? How are we related to one another? If so, what can we learn from one another? So, that’s the motivation for a lot of people on our panel to go to work on a daily basis.”

The report from the National Academy of Sciences Committee on Exoplanet Science Strategy will be reviewed by Congress. Portions of it may be included in the final 2020-2030 Astronomy and Astrophysics Decadal Survey, which will fund the continuing search for exoplanets and the study of extraterrestrial life. (VOA)

Next Story

Asteroids Are Falling On Earth’s Surface Twice As Often: Study

This enhanced impact rate poses a threat for the next mass extinction event.

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Asteroids
This Dec. 29, 1968, photo made available by NASA shows craters on the moon. For the past 290 million years, giant rocks from space have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study. VOA

Giant rocks from space are falling from the sky more than they used to, but don’t worry.

For the past 290 million years, large asteroids have been crashing into Earth more than twice as often as they did in the previous 700 million years, according to a new study in Thursday’s journal Science.

But no need to cast a wary glance up. Asteroids still only smack Earth on average every million or few million years, even with the increased crash rate. NASA’s list of potential big space rock crashes shows no pending major threats. The biggest known risk is a 4,200-foot (1.3-km) wide asteroid with a 99.988 percent chance that it will miss Earth when it whizzes very near here in 861 years.

Tell that to the dinosaurs. Most scientists think dinosaurs and a lot of other species went extinct after a huge space rock crashed into Central America about 65 million years ago.

Earth, Asteroids
Taurids meteor shower lights up the sky. The risk of asteroids hitting the Earth has grown over the years. Wikimedia

“It’s just a game of probabilities,” said study lead author Sara Mazrouei, a University of Toronto planetary scientist. “These events are still rare and far between that I’m not too worried about it.”

Mazrouei and colleagues in the United Kingdom and United States compiled a list of impact craters on Earth and the moon that were larger than 12 miles (20 km) wide and came up with the dates of them. It takes a space rock that’s half a mile (800 meters) wide to create holes that big.

The team counted 29 craters that were no older than 290 million years and nine between 291 million years and 650 million years old.

But we can see relatively few big craters on Earth because the planet is more than 70 percent ocean and past glaciers smoothed out some holes, said University of Toronto planetary scientist Rebecca Ghent, a study co-author.

Earth, Asteroids
These rocks were rare survivors from a very different time on Earth. Pixabay

Extrapolating for what can’t be seen brings the total to about 260 space crashes on Earth in the last 290 million years. Adding in other factors, the science team determined that the current space crash rate is 2.6 times more than the previous 700 million years.

Craters older than 650 million years are mostly wiped off on Earth by glacial forces so the scientists used impact craters on the nearby moon as a stand-in for holes between 650 million and 1 billion years old. The moon is a good guide for estimating Earth crashes, because it is close enough to be in the same bombardment path and its craters last longer.

Mixed reactions

So what happened nearly 300 million years ago?

“Perhaps an asteroid family was broken up in the asteroid belt,” Mazrouei speculated. The space rocks then headed toward the Earth and moon, and the planet got slightly more because it is a bigger target and it has higher gravity, Ghent said.

Oldest known asteroid family
An asteroid family. Wikimedia

Outside scientists are split about the research. Jay Melosh at Purdue said he found the number of craters too small to come to a reasonable conclusion, but Harvard’s Avi Loeb said the case was convincing.

Also Read: Newly Discovered Super-Earth Exoplanet May Sustain Primitive Life

Humans might not have emerged without mass extinctions from space rocks about 250 million and 65 million years ago, Loeb said in an email, adding, “but this enhanced impact rate poses a threat for the next mass extinction event, which we should watch for and attempt to avoid with the aid of technology.”

“This demonstrates how arbitrary and fragile human life is,” Loeb wrote. (VOA)