TRAPPIST-1 Habitability Possible; LISA Passes Milestone; Super/Blue/Blood Moon Next Week! | SFN #222

Astronomers publish a paper claiming the two of the earth-sized planets around TRAPPIST-1 are potentially habitable; the LISA Mission passes a critical Mission Design Readiness Review; and next week when Space Fans look up, superbluebloodmoontime!

4138 Views | Published on 26th Jan, 2018

Hello space fans and welcome to another edition of Space Fan News. In this episode, astronomers publish a paper claiming the two of the earth-sized planets around TRAPPIST-1 are potentially habitable; the LISA Mission passes a critical Mission Design Readiness Review; and next week when Space Fans look up, there’s a special treat in store for us - that is if you like superbluebloodmoons.

By now, most of you have heard about the TRAPPIST-1 system, this is the place that, in 2015 was found to have three Earth-sized planets then an additional four more was discovered last year. Everybody got all excited because at least three of those seven planets were considered in the habitable zone of the star.

Well, this week astronomers published a paper suggesting that at least two of those planets - d and e - are most likely habitable. How do they figure that?

The TRAPPIST-1 star is very old and dim, making the surfaces of the planets have relatively cool temperatures by planetary standards, ranging from 400 degrees Kelvin (260 degrees Fahrenheit or 127 degrees Celsius), which is cooler than Venus, all the way down to 167 degrees Kelvin (-159 degrees Fahrenheit or -106 Celsius), which is colder than Earth’s poles.

So habitable, sure if you’re a well-insulated polar bear with a removable coat.

Other things affecting habitability: the planets also orbit very close to the star, with orbital periods of a few days. And their orbits are eccentric –not quite circular – which means these planets could experience tidal heating just like the moons of Jupiter and Saturn.

And that tidal heating makes things even cozier.

Moreover, as icing on the cake, a global water ocean likely covers planet d. How they came to that conclusion though, I haven’t been able to find out.

The researchers used the assumption that the planets are made of water ice, rock and iron then incorporated what the geologic layers would be from the planet's’ orbital path. Since the planet’s orbital characteristics are not well defined, the surface conditions may vary from the average of the study's findings.

So, while planets d and e are considered potentially habitable and may have liquid water, the team went further and calculated the balance between tidal heating and heat transport by convection in the mantles of the rest of the planets.

The results show that planets b and c likely have partially molten rock mantles (this is the inner layer of a rocky planet). The paper also shows that planet c likely has a solid rock surface, and could have eruptions of silicate magmas on its surface driven by tidal heating, similar to Jupiter’s moon Io.

Next, with gravitational waves all the rage in astrophysics these days, I wanted to give you an update on the LISA Mission. LISA is the space-based, Laser Interferometer Space Antenna and it will be the supercharged version of LIGO which has made several observations of gravitational wave events over the last couple of years.

This week it was announced that the LISA mission has just passed a major review milestone. Basically it was decided that LISA:

Is feasible and suitable (that’s good)

The mission requirements meet LISA’s science requirement (always a good thing)

The requirements are mature and adequate (OK)

The Technology developments are adequate (no Best Buy stuff here)

And the interfaces between the spacecraft, payload ground segment and the launcher are well-defined.

LISA is scheduled to launch in 2034 and while I know that’s a long way off, keep in mind that JWST was on the drawing board for decades, everything is on track for it’s launch.

LISA is lead by ESA and is a consortium of many nations space programs including NASA (the finally decided they wanted to be included after dropping the mission entirely a couple of years ago).

So there you go, LISA is getting dressed up and will soon be ready to start the next phase. I for one am very excited about this mission because it promises to do for gravitational wave astronomy what Hubble and JWST have done for optical and infrared astronomy.

LISA will consist of three satellites spanning an equilateral triangle with each side approx. 2.5 million kilometers long. Gravitational waves passing through the constellation change these distances by a fraction of the diameter of an atom. LISA´s key technologies were successfully demonstrated with ESA´s LISA Pathfinder mission, which operated from late 2015 until mid-2017.

LISA will measure low-frequency gravitational waves with oscillation periods ranging from 10 seconds to more than half a day, which cannot be observed with detectors on the earth. These are emitted by events such as supermassive black holes with millions of times the mass of our Sun merging at the centers of galaxies, the orbital motions of tens of thousands of binary stars in our Galaxy, and possibly exotic sources such as cosmic strings.

Once in place, LISA will look into the highest energy events and see the fabric of existence.

I will keep you posted.

Finally, in the ‘This is why we Keep Looking Up Dept’, in just a few days, during the early morning hours of January 31st, just a few days away, the Sun, Earth, and Moon are going show the people of Indonesia and New Zealand a spectacular view of the lunar eclipse. We in the States and North America will not be left out. If you stay up all night or wake up very early in the morning in California, just before 5 am to be precise, you will see a lunar trifecta: a supermoon that is also a blue moon that is visible during a lunar eclipse.

A supermoon is the tiresome label we’ve been using lately to describe a full moon (which happens every month) but happens when the moon is also closest to us. Something called perigee.

Since the Moon’s orbit is elliptical, one side (apogee) is about 30,000 miles (50,000 km) farther from Earth than the other (perigee). Nearby perigee full Moons - or supermoons - appear about 14% bigger and 30% brighter than full Moons that occur near apogee in the Moon's orbit.

In all the years I’ve been looking up, I’ve never really noticed much difference when I look at supermoons, so it’s hard for me to get excited about it. But still, there it is supermoon time and if that’s all that was happening, I’d never mention it in an SFN episode, but luckily the event is more interesting that that.

This will also be a blue moon, which is the second full moon that occurs in the same month. Usually these happen only in long months, those that have 31 days because the lunar phase cycle is 29.5 days (going from full moon to full moon).

But wait! That’s not all. If you look up now, you’ll also be treated to a full lunar eclipse on some parts of the planet. Totality will be viewable from western North America across the pacific to Eastern Asia.

Why don’t we see lunar eclipses every month? Well, the Moon’s orbit around our planet is tilted so it usually falls above or below the shadow of the Earth and we don’t see an eclipse. But about twice each year, a full Moon lines up perfectly with the Earth and Sun such that Earth’s shadow totally blocks the Sun’s light, which would normally reflect off the Moon.

Here in the eastern United States, I will only see a partial lunar eclipse so to me, and when you see them, they have a reddish tinge to them because of the Earth’s atmosphere filtering out the solar light as it hits the moon. Because of this lunar eclipses are also called Blood moons.

So there you go: early next Wednesday on January 31st, go outside and look up at the Super/Blue/Blood Moon as it totally eclipses your mind!

That’s it for this episode Space Fans, I want to thank all of the awesome deep astronomy patreon patrons who keep the lights on here at Deep Astronomy.

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Thank you all for watching and as always.

Keep Looking Up!


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