Archive for the 'Astronomy' Category

Mar 10 2017

Fast Radio Bursts and Alien Life

Published by under Astronomy

frb-alienFast radio bursts (FRBs) are brief, bright, and distant bursts of radio emissions that are of unknown origin. Recently they have been in the news because of a paper which explores the feasibility that FRBs have an alien origin.

“Fast radio bursts are exceedingly bright given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” said theorist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “An artificial origin is worth contemplating and checking.”

Let me first give a little more background on FRBs and then we can discuss the alien hypothesis.

Fast Radio Bursts

The first thing to know about FRBs is that they are, indeed, fast. They typically last only a few milliseconds (thousandths of a second). Recorded FRBs range from 0.05 ms to 9.4 ms. That is extremely brief.

They are broadband radio bursts, meaning that they cover a broad frequency range.

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12 responses so far

Mar 06 2017

Terraforming Mars

Published by under Astronomy

MarsTransitionVHow high a priority should we have for sending people to Mars? This seems to be a big question these days. NASA is developing the Space Launch System (SLS) and the Orion capsule specifically to have the capacity to send people to Mars. Elon Musk has stated that the real purpose of SpaceX is to colonize Mars.

The public imagination has also been sparked by movies such as The Martian (which was excellent). I also recommend National Geographics’ series “Mars” which is a combination of interviews with current scientists and engineers about the problems that a Mars colony would face, with a narrative about a future colonization mission.

The one fact that everyone agrees on is that colonizing Mars will be extremely difficult. Mars has an atmosphere about 1% that of Earth. This makes it just thick enough to be a problem but not thick enough to help with breaking while landing on Mars, and not thick enough to make the surface any more livable. A 1% atmosphere is effectively a vacuum, but it is enough to cause planet-wide dust storms that would make life on Mars challenging.

Transfer to Mars would take about 8 months with current rocket technology. Depending on the relative position of the planets and the transfer speed, 130-260 days are the figures most often cited. That means supply lines would be very difficult, and don’t expect any rescue missions.

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11 responses so far

Jan 27 2017

Scientists Create Metallic Hydrogen

jupiter-magnetic-fieldIt was just announced that for the first time scientists were able to create a small amount of metallic hydrogen in the lab. This is a significant breakthrough, and is sure to lead to further discovery, although it remains to be seen what specific practical applications may emerge.

Hydrogen, as most people know, is a gas at familiar temperatures and pressures. The universe is comprised of about 90% hydrogen. There is very little free hydrogen on the Earth, since it is a very light gas, but there is lots of hydrogen bound up in molecules, such as water.

In 1935, physicists Eugene Wigner and Hillard Bell Huntington hypothesized that under extreme pressure hydrogen atoms may form into a metal – metallic hydrogen. The point at which this happens was named the Wigner-Huntington transition, which explains the title of the recent paper. Metallic hydrogen can further be a liquid, in which the electrons and protons are free flowing, or they can form a crystalline structure and be a solid.

Astronomers infer that the core of Jupiter may be hot liquid hydrogen. We know that Jupiter is made mostly of hydrogen, and we can calculate that the pressure deep in Jupiter’s core must have millions of times the pressure on the surface of the Earth. That is sufficient pressure, according to theory, to compress hydrogen into its metallic form.

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19 responses so far

Oct 25 2016

234 Possible Alien Signals

Published by under Astronomy,Skepticism

alien-worldI love reading articles that discuss the same issue and come to essentially opposite conclusions. In this case, Canadian astronomers have recently performed an analysis of 2.5 million stars and found 234 of them producing pulsed signals that they claim may be of alien origin. The scientific community is skeptical.

The Independent declares, “Strange messages coming from the stars are ‘probably’ from aliens, scientists say.” Meanwhile, worldofwierdthings.com states, “Why hundreds of aliens probably aren’t trying to contact us.”

When you read deep into both articles you find a more nuanced position. The difference is mostly in the headline writing, but also in the overall emphasis of the article. Skepticism can be marginalized or central.

SETI and Skepticism

I have found the search for extraterrestrial intelligence (SETI) to be an excellent topic of skeptical discussion. It is a great forum for discussing what is legitimate science, and how scientists decide whether something is likely to be true or not. There is nothing supernatural or paranormal about life evolving on exoplanets, intelligence emerging, and developing a technological civilization that might send signals out into space. We have done it.

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71 responses so far

Aug 25 2016

When Will Life Exist?

Published by under Astronomy

proximabThe Drake Equation is a thought experiment identifying which variables are needed to calculate the number of intelligent civilizations in the universe. Some people criticize the equation because we can only guess at the values of those variables, but that is not the point. The point was to identify the variables. This allows us to take the next step in the thought experiment, to plug in possible values and see what answers we get. Also, over time we will get better and better estimates of those variables.

Recently astronomers Loeb, Batista and Sloan published a paper in which they did a similar thought experiment, but instead of asking how common life and intelligent life is in the universe right now, they asked how common life is likely to be over the lifetime of the universe.

Their conclusion:

We find that unless habitability around low mass stars is suppressed, life is most likely to exist near ~ 0.1M stars ten trillion years from now.

Ten trillion years is a long time, given that the universe is only 13.82 billion years old. What they are saying is that there are many low mass stars, or red dwarfs, in the universe. Further, low mass stars have a very long lifespan, hundreds of billions and even trillions of years. About 76.45% of all the stars out there are red dwarfs, and a star with 0.1 solar masses (a tenth the mass of our sun) could survive for 10 trillion years according to our models of stellar physics.

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24 responses so far

Jul 21 2016

Dark Matter and Dark Energy

Published by under Astronomy

Winter_Dark_Matter_CFHTLenS_alternative_colour

Genuine mysteries in science are fascinating, and there is no shortage of them. Scientists love mysteries because that is where the work is.

Two of the biggest scientific mysteries of our generation have similar names – dark matter and dark energy. Their names imply the unknown. They are, in fact, place-holder concepts that are temporarily representing what we don’t know. However, we are  slowly crawling toward an understanding of what they are.

Dark energy makes up about 70% of the mass/energy of the universe, while dark matter makes up another 25%, leaving just 5% for ordinary matter and energy. This means we currently don’t know what 95% of the universe is made of.

Fritz Zwicky first proposed the existence of dark matter in 1933, but his ideas were not accepted until the 1970s when they were revived by two astronomers, Vera S. Rubin and W. Kent Ford Jr. The hypothesis derives from the observation of how galaxies rotate. Their rate of rotation depends upon the amount of matter they contain – the more mass that exists within the orbit of any particular star, the faster that star will revolve about that galaxy. You can therefore estimate the amount of mass in a galaxy by observing how fast the stars are moving.

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32 responses so far

Apr 01 2016

Should We Hide From Aliens

Published by under Astronomy

transit-352Given the date today, I had to be careful. Is the Royal Institution investigating quantum astrology? No, but those Brits can be quite cheeky.

When I saw this headline, Lasers could ‘cloak Earth from aliens’ on the BBC website, I thought they might be having a laugh. The alternative was a bit of hyperbole in science news reporting, which is a daily occurrence. The paper on which the item is based was officially published on March 30, so I think it’s legit.

What’s going on here is that two astronomers, David M. Kipping, and Alex Teachey, did a thought experiment – what would it take to disguise the Earth from aliens using the transit method to discover the Earth? Continue Reading »

22 responses so far

Feb 02 2016

NASA – Defending Earth

Published by under Astronomy

asteroid-threat-global-action-plan-101109-02NASA recently announced that it has created a Planetary Defense Coordination Office (PDCO). The purpose of this new office is to defend the Earth from alien invasion.

OK, no, but the name does sound like that, doesn’t it?

The purpose of the office is to coordinate efforts to defend the Earth from Near Earth Objects (NEOs) – essentially comets and asteroids on a collision course with the Earth. The director is Lindley Johnson, who is currently the NEO program executive, which is an obvious fit with the new office.

NEOs do pose a threat to our civilization. You don’t have to be Bruce Willis to imagine how devastating it could be for a large rock traveling faster than a bullet to hit the Earth. Of course, the answer is that it could fall anywhere along a spectrum from nothing to wiping out our entire species. Obviously NASA is more concerned with the latter.

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11 responses so far

Oct 02 2015

The Problem of Space Junk

Published by under Astronomy

We have been putting stuff into orbit around the Earth, especially low-Earth orbit, for the last 58 years. Space is a big place, so no one probably worried at first that we would start junking it up, but that is exactly what has happened in this short span of time. This is now a serious issue we have to confront.

It’s disappointing, and I hate having one more thing to worry about, but Earth orbit has become so cluttered with debris that it poses a serious risk to our assets in space. Recently former NASA scientist Donald Kessler said in an interview:

“We’re at what we call a ‘critical density’ — where there are enough large objects in space that they will collide with one another and create small debris faster than it can be removed.”

NASA scientists also fear a scenario similar to that portrayed in the movie, Gravity. There were some scientific problems with the movie, but the core idea is valid – there is so much debris in orbit that a collision of two large objects can start a chain-reaction, they will scatter debris which will collide with other objects causing more debris.

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6 responses so far

Jul 14 2015

Why Pluto is Important

Published by under Astronomy

As I write this post we are just minutes away from the closest approach of the New Horizons probe to Pluto, the farthest world we have thus far explored (24 minutes and counting). It’s an exciting moment, not just for astronomy buffs or science enthusiasts, but for humanity. I’m glad to see an appropriate level of excitement among the media and the general public.

Still, a couple of people have commented to me or in my presence that they don’t understand what the big deal is or why this is important, so allow me a moment to explore why I think this is such a big deal.

First, let us not forget what it took to get there. New Horizons is the fastest thing humans ever built. It shot past the moon in 8 hours and 35 minutes, and made a journey of 5 billion kilometers (or 5 terameters, as my friend the Metric Maven would say). On its way it swung around Jupiter to get a gravity assist.

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40 responses so far

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