Would We See the Aliens Coming?

If aliens were heading towards the Earth, would we see them coming?

Classic sci fi trope time. The air force detects a fleet of alien spacecraft out past Jupiter, leaving enough time to panic and demonstrate what awful monsters we truly are before they come ring our bell.
Is that how this would work?

Imagine a pivotal scene in your favorite alien mega disaster movie. Like the one where the gigantic alien ships appear over London, Washington, Tokyo, and Paris and shoots its light-explody ray, obliterating a montage of iconic buildings. Demonstrating how our landmark construction technology is nothing against their superior firepower.

What could we do? We’re merely meat muppets with pitiful silicon based technology. How could we ever hope to detect these aliens with their stealth spacecraft and 3rd stage guild navigators? If we’re going to do this, I’m going to make up some rules. If you don’t like my rules, go get your own show and then you can have your own rules.

Alternately, as some of you are clearly aware, you can rail against the Guide To Space in the comments below. Dune reference notwithstanding, I’m going to assume that aliens live in our Universe and obey the laws of physics as we understand them. And I know you’re going to say, what if they use physics we haven’t discovered yet?

Then just pause this video and get that out of your system. You can make that your first decree against the state right in the comments below. As I was saying, physical aliens, physical universe. We’ll discuss the metaphysical aliens in a magic universe in a future video. The ones that have crystals and can heal your liver through the power of song.

A basic rule of the Universe is that you can’t go faster than the speed of light. So I’m going to have any aliens trying to attack us traveling at sublight speeds.

So, we’ll say they’ve got access to a giant mountain of power. They can afford to travel at 10% the speed of light, which means before they get to us, they have to slow down. At this speed, deceleration is expensive. We’d see the energy signature from their brakes long before they even reached Earth.

Let’s say they’re passing the orbit of the dwarf planet Pluto, which is 4 light-hours away. Since they’re travelling at 10% the speed of light, we’d have about 40 hours to scramble jet fighters, get those tanks out onto the streets and round up Will Smith, Jeff Goldblum and Bruce Willis to hide behind.

A composite image with Chandra data (purple) showing a "point-like source" beside the remains of a supernova, suggesting a companion star may have survived the explosion. Credit: X-ray: NASA/CXC/SAO/F.Seward et al; Optical: NOAO/CTIO/MCELS, DSS
A composite image with Chandra data (purple) showing a “point-like source” beside the remains of a supernova, suggesting a companion star may have survived the explosion. Credit: X-ray: NASA/CXC/SAO/F.Seward et al; Optical: NOAO/CTIO/MCELS, DSS

Would we even notice? Maybe, or maybe not. A growing trend in astronomy is scanning the sky on a regular basis, looking for changes. Changes like supernova explosions, asteroids and comets zipping past, and pulsating variable stars.

One of the most exciting new observatories under construction is the Large Synoptic Survey Telescope in Chile. Once it begins regular operations in 2022, this array of telescopes will photograph the entire sky in fairly high resolution every few nights.

Computers will process the torrent of data coming from the observatory and search for anything that changes. What if they engage their cloak?

Actually (push glasses up your nose) the laws of physics say that the aliens can’t hide the waste heat from whatever space drive they’re using. We’re actually pretty good at detecting heat with our infrared telescopes.

A space drive decelerating a city-sized alien spacecraft from a significant portion of the speed of light would shed a mountain of heat, and that’s all heat we might detect.

Astronomers have been searching for alien civilizations by looking for waste heat generated by Dyson spheres encapsulating entire stars or even all the stars in a galaxy. Nothing’s turned up yet. Which I for one, find a little suspicious.

Freemon Dyson theorized that eventually, a civilization would be able to build a megastructure around its star to capture all its energy. Credit: SentientDevelopments.com
Freemon Dyson theorized that eventually, a civilization would be able to build a megastructure around its star to capture all its energy. Credit: SentientDevelopments.com

If you’re from an alien race who’s planning to invade. Cover your ears. If aliens wanted to catch us off guard, they can use one of the oldest tricks in the aerial combat book, known as the Dicta Boelcke. They can fly at us using the Sun as camouflage. A rather large portion of the sky is completely obscured by that glowing ball of fiery plasma. It worked in WW1, and it’ll still work now.

Okay, aliens you can listen in again. Everyone else might want to mute the next part, as it’s not terribly reassuring. Astronomers often discover asteroids skimming by the Earth just after they’ve just gone past. That’s because they hurl at us from the Sun, just like clever aliens.

To spot those asteroids, we’ll need to deploy a space-based sky survey that can watch the heavens from a different perspective than Earth. Plans for this kind of mission are actually in the works.

Even with our rudimentary technology, we’d actually stand a pretty good chance of noticing the alien attack vessels before they actually arrived at centre of Sector 001. It’ll get better with automated observatories and space-based sky surveys.

Of course, there’s little we can do if we did know the aliens were coming. We’d be best to start with some kind of deterrent, contaminate all our fresh water, load our livestock up on antibiotics and cover our cities in toxic smog to deter the harvesting of our citizens.

Do you think we’d stand a chance against an alien invasion? Tell us how we’d do in the comments below.

Largest Digital Camera Ever Constructed will be Pointed at the Skies in 2022

The world’s largest-ever digital camera has received the green light to move forward with development. The 3,200-megapixel camera for the Large Synoptic Survey Telescope (LSST) will snap the widest, deepest and fastest views of the night sky ever observed, providing unprecedented details of the Universe. Astronomers say the LSST will help uncover some of the biggest mysteries in astronomy.

The SLAC National Accelerator Laboratory announced this week they have received key “Critical Decision 2” approval from the Department of Energy.

“This important decision endorses the camera fabrication budget that we proposed,” said LSST Director Steven Kahn. “Together with the construction funding we received from the National Science Foundation in August, it is now clear that LSST will have the support it needs to be completed on schedule.”

A rendering of the LSST Camera with a cut away to show the inner workings. Credit: LSST.
A rendering of the LSST Camera with a cut away to show the inner workings. Credit: LSST.

Set to begin science operations in 2022, the LSST will create an unprecedented archive of astronomical data that will track billions of remote galaxies, helping researchers study galaxy formation. It will rapidly scan the sky, charting objects that change or move: from exploding supernovae to potentially hazardous near-Earth asteroids and create high resolution time-lapse videos of these objects and a 3-D map of the Universe. It will also help us better understand mysterious dark matter and dark energy, which make up 95 percent of the Universe

The camera itself will be the size of a small car and weigh more than 3 tons. It will be able to take up to 800 panoramic images each night and can cover the sky twice each week. Researchers say it will have the ability to reach faint objects twenty times faster than currently possible over the entire visible sky. Scientists anticipate LSST will generate 6 million gigabytes of data per year.

The unique LSST M1/M3 mirror surfaces being carefully polished. Credit: E. Acosta / LSST Corporation.
The unique LSST M1/M3 mirror surfaces being carefully polished. Credit: E. Acosta / LSST Corporation.

The telescope will have an 8.4-meter-diameter primary mirror that has an integrated 5-meter-diameter tertiary mirror. This mirror has already been fabricated at the University of Arizona’s Mirror Lab. The outer ring serves as the first mirror, and is called M1. Another more steeply curved mirror, M3, is carved out of the center. It has a 3-degree field of view.

LSST will be taking digital images of the entire visible southern sky every few nights from atop the Cerro Pachón mountain in Chile.

Cerro Pachon is already home to the Gemini South 8-meter telescope and the SOAR 4.1-meter telescope. This graphic also shows LSST's future site.  Credit:  C. Claver, NOAO/LSST
Cerro Pachon is already home to the Gemini South 8-meter telescope and the SOAR 4.1-meter telescope. This graphic also shows LSST’s future site. Credit: C. Claver, NOAO/LSST

Amateur and armchair astronomers will be happy to know that data from the LSST will be shared publicly and become available quickly via the internet. Researchers involved are planning to involve the public, including students, by using portals like Google Sky or World Wide Telescope, as well as developing research projects that can be done by students in classroom settings, and the public at home and at settings like science museums. They also hope to utilize citizen science projects like Cosmoquest and Galaxy Zoo.

With the latest approval from the DOE, the LSST team can now move forward with the development of the camera. There will be a “Critical Decision 3” review process next summer, which will be the last requirement before actual fabrication of the camera can begin. Components of the camera will be built by an international collaboration of labs and universities.

Sources: SLAC, LSST FAQ