Category Archives: Cool Stuff

To Scale: The Solar System

A great video by Wylie Overstreet and Alex Gorosh.

I even do this every now and then myself just for fun and I get a bit of exercise in the process. I don’t do it quite the way Wylie and Alex did  as I just pace off this distances but even so, it is very interesting.

This is a GREAT activity for children!  Depending on what scale you use for distance you all you will need is a flat piece of ground, like say a football pitch. Even at one step per 10 million kilometers you can get a pretty long ways away from the starting point so plenty of room is helpful.

You can change the scale to fit your needs as long as you are looking at distance and not necessarily planetary sizes; also a good exercise for youngsters to exercise their brains during the school holiday.

To get you started have a look at this page from the Lunar and Planetary Institute.

ESA’s JUICE

This ‘family portrait’ shows a composite of images of Jupiter, including it’s Great Red Spot, and its four largest moons. From top to bottom, the moons are Io, Europa, Ganymede and Callisto. Europa is almost the same size as Earth’s moon, while Ganymede, the largest moon in the Solar System, is larger than planet Mercury.
While Io is a volcanically active world, Europa, Ganymede and Callisto are icy, and may have oceans of liquid water under their crusts. Europa in particular may even harbour a habitable environment.
Jupiter and its large icy moons will provide a key focus for ESA’s JUICE mission. The spacecraft will tour the Jovian system for about three-and-a-half years, including flybys of the moons. It will also enter orbit around Ganymede, the first time any moon beyond our own has been orbited by a spacecraft.
The images of Jupiter, Io, Europa and Ganymede were taken by NASA’s Galileo probe in 1996, while the Callisto image is from the 1979 flyby of Voyager.

The JUICE mission sounds like a typical ESA mission — ambitious and well planned.  It should be exciting, even if there is a long tome until launch.  Read more about the JUICE mission here.

What Makes Drizzle Drizzle?

Image: Wikimedia Commons contributor GerritR, CC BY-SA 4.0 via NASA.

A recent NASA study sheds some light on what makes drizzle. I have to admit to really “geeking-out” after reading the following from Carol Rasmussen (NASA’s Earth Science News Team) – especially the end.

NASA – A new NASA study shows that updrafts are more important than previously understood in determining what makes clouds produce drizzle instead of full-sized raindrops, overturning a common assumption.

The study offers a pathway for improving accuracy in weather and climate models’ treatments of rainfall — recognized as one of the greater challenges in improving short term weather forecasts and long-term climate projections.

The research by scientists at NASA’s Jet Propulsion Laboratory in Pasadena, California; UCLA; and the University of Tokyo found that low-lying clouds over the ocean produce more drizzle droplets than the same type of cloud over land. The results are published online in the Quarterly Journal of the Royal Meteorological Society.

Water droplets in clouds initially form on microscopic airborne particles, or aerosols. Scientists have been studying the role of aerosols in clouds and rain for decades. There are more aerosols over land than over the ocean, and scientists had thought the additional aerosols would tend to form more drizzle over land as well. The new study shows that the presence of aerosols alone can’t explain where drizzle occurs.
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A Solar Flare and More

Here is a view of the solar flare of 17 July from the Solar Dynamics Observatory. The video is a great example of where you would expect to see sunspots at this stage in the solar cycle.

If you start watching sunspot activity about now, you will notice that most of sunspots will be in the general equatorial region (+/- 20 degrees or so) and not in the high latitudes as we near the solar minimum.

As time goes on sunspots will start appearing in the high latitudes so we have spots in both areas.  The high latitude spots could herald a new cycle, IF they are polarized reverse from the current cycle.  Yes, sunspots are polarized and that reverses every cycle.  So all scientists have to do is look at how the spots are polarized; with EVERY cycle the polarization of the new cycle spots are reverse of the old cycle.  There is no “solid wall” with cycle changes, the new cycle mixes into the old.  The cycle repeats about every 11 years.

Eventually the whole Sun will will reverse polarity!  Yes, that happens with EVERY cycle change and usually around the maximum point in the cycle.

Just because we are nearing the end of a solar cycle does not mean powerful eruptions on the sun won’t take place. Over the weekend (23 July) there was a Coronal Mass Ejection (CME) on the opposite side of the sun the likes of which are seldom seen. In fact I’ve heard comparisons to the Carrington Event of 1859. If that were to happen today, I would not be surprised in the least to see wide spread power and satellite interruptions – yes it’s that significant. Everyone is watching for the return of the region in about two to see how it has held together.

Magnetic Reconnection

Earlier this week I had a fellow telling me about magnetic portals that threaten Earth that have just started showing up and “oh my goodness”.

Given the grin I had upon my face at hearing the news, especially from him because he learned all about it from the internet and he tends towards the conspiracy sides of things if you know what I mean. I don’t think he believed me when I told him to relax.

So I thought I’d post a couple of videos explaining correctly what he was all excited about because magnetic reconnection is REAL, but not quite like he thinks.

See what the MMS mission is about and learning, first this:

and then this:

Phobos in Orbit

Check this out – Hubble captures the Martian moon Phobos in orbit.

/
Goddard Space Flight Center/NASA/ESAHubble — A football-shaped object just 16.5 miles by 13.5 miles by 11 miles, Phobos is one of the smallest moons in the solar system. It is so tiny that it would fit comfortably inside the Washington, D.C. Beltway.

The little moon completes an orbit in just 7 hours and 39 minutes, which is faster than Mars rotates. Rising in the Martian west, it runs three laps around the Red Planet in the course of one Martian day, which is about 24 hours and 40 minutes. It is the only natural satellite in the solar system that circles its planet in a time shorter than the parent planet’s day.

About two weeks after the Apollo 11 manned lunar landing on July 20, 1969, NASA’s Mariner 7 flew by the Red Planet and took the first crude close-up snapshot of Phobos. On July 20, 1976 NASA’s Viking 1 lander touched down on the Martian surface. A year later, its parent craft, the Viking 1 orbiter, took the first detailed photograph of Phobos, revealing a gaping crater from an impact that nearly shattered the moon.

Phobos was discovered by Asaph Hall on August 17, 1877 at the U.S. Naval Observatory in Washington, D.C., six days after he found the smaller, outer moon, named Deimos. Hall was deliberately searching for Martian moons.

Both moons are named after the sons of Ares, the Greek god of war, who was known as Mars in Roman mythology. Phobos (panic or fear) and Deimos (terror or dread) accompanied their father into battle.

Close-up photos from Mars-orbiting spacecraft reveal that Phobos is apparently being torn apart by the gravitational pull of Mars. The moon is marred by long, shallow grooves that are probably caused by tidal interactions with its parent planet. Phobos draws nearer to Mars by about 6.5 feet every hundred years. Scientists predict that within 30 to 50 million years, it either will crash into the Red Planet or be torn to pieces and scattered as a ring around Mars.

Orbiting 3,700 miles above the Martian surface, Phobos is closer to its parent planet than any other moon in the solar system. Despite its proximity, observers on Mars would see Phobos at just one-third the width of the full moon as seen from Earth. Conversely, someone standing on Phobos would see Mars dominating the horizon, enveloping a quarter of the sky.

From the surface of Mars, Phobos can be seen eclipsing the sun. However, it is so tiny that it doesn’t completely cover our host star. Transits of Phobos across the sun have been photographed by several Mars-faring spacecraft.

The origin of Phobos and Deimos is still being debated. Scientists concluded that the two moons were made of the same material as asteroids. This composition and their irregular shapes led some astrophysicists to theorize that the Martian moons came from the asteroid belt.

However, because of their stable, nearly circular orbits, other scientists doubt that the moons were born as asteroids. Such orbits are rare for captured objects, which tend to move erratically. An atmosphere could have slowed down Phobos and Deimos and settled them into their current orbits, but the Martian atmosphere is too thin to have circularized the orbits. Also, the moons are not as dense as members of the asteroid belt.

Phobos may be a pile of rubble that is held together by a thin crust. It may have formed as dust and rocks encircling Mars were drawn together by gravity. Or, it may have experienced a more violent birth, where a large body smashing into Mars flung pieces skyward, and those pieces were brought together by gravity. Perhaps an existing moon was destroyed, reduced to the rubble that would become Phobos.

Hubble took the images of Phobos orbiting the Red Planet on May 12, 2016, when Mars was 50 million miles from Earth. This was just a few days before the planet passed closer to Earth in its orbit than it had in the past 11 years.

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

Supersonic Parachute

I am always amazed at parachute tests,.  A capsule (see link below) is speeding along at 12 times the speed of sound and then the parachute is deployed creating incredible stresses on the system, in the end designs it all holds together. For some unknown reason this test got me to wondering how much stretch the attaching parachute cord occurs and what the tensile strength is, for that matter what it is made of.   Oh I’m sure the data is out there, I just need to find it.

About the test:
ESA — This parachute deployed at supersonic velocity from a test capsule hurtling down towards snow-covered northern Sweden from 679 km up, proving a crucial technology for future spacecraft landing systems.

Planetary landers or reentering spacecraft need to lose their speed rapidly to achieve safe landings, which is where parachutes come in. They have played a crucial role in the success of ESA missions such as ESA’s Atmospheric Entry Demonstrator, the Huygens lander on Saturn’s moon Titan and the Intermediate Experimental Vehicle spaceplane.

This 1.25-m diameter ‘Supersonic Parachute Experiment Ride on Maxus’, or Supermax, flew piggyback on ESA’s Maxus-9 sounding rocket on 7 April, detaching from the launcher after its solid-propellant motor burnt out.

After reaching its maximum 679 km altitude, the capsule began falling back under the pull of gravity. It fell at 12 times the speed of sound, undergoing intense aerodynamic heating, before air drag decelerated it to Mach 2 at an altitude of 19 km.

At this point the capsule’s parachute was deployed to stabilise it for a soft landing, and allowing its onboard instrumentation and camera footage to be recovered intact.

The experiment was undertaken by UK companies Vorticity Ltd and Fluid Gravity Engineering Ltd under ESA contract.

The data gathered by this test are being added to existing wind tunnel test campaigns of supersonic parachutes to validate newly developed software called the Parachute Engineering Tool (also developed by Vorticity), allowing mission designers to accurately assess the use of parachutes.

BepiColombo Acoustic Test

Very pleased to see a BepiColombo online and at an acoustic test no less. I wondered how they tested for acoustics, was a shake-test enough?  Apparently not.

ESA – The full BepiColombo stack seen in the Large European Acoustic Facility (LEAF) at ESA’s test centre in June 2017. The walls of the chamber are fitted with powerful speakers that reproduce the noise expected during launch.

From bottom to top: the Mercury Transfer Module (sitting on top of a the cone-shaped adapter), the Mercury Planetary Orbiter (with an antenna facing towards the camera), and the sunshield (top), within which sits the Mercury Magnetospheric Orbiter.

The noise of a launch is incredible! The echo is so strong it could knock tiles off a Space Shuttle. The noise is mitigated so some degree with suppression systems, ever wonder what the water is for during launches, it is noise suppression.

Credit: ESA–C. Carreau, CC BY-SA 3.0 IGO