Exoplanets & Diabetes | SciByte 135

chris

8 years ago

Hello everyone and welcome back to SciByte!

We take a look at adding and subtracting exoplanets, diabetes research, spacecraft updates, viewer feedback, Curiosity news, and as always take a peek back into history and up in the sky this week.

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Exoplanets? … Not So Fast

The controversial existence of two possible planets located in the habitable zone of a star now have a ‘final’ ending to their story
Last Time on SciByte, … well J@N
Planet Zarmina | J@N | 10.6.10
Gliese 581 System
Planets were first announced around the system in 2007
September 30, 2010 | Gliese 581d and 581g
There was the possible discovery of the closest Earth-sized planet found found at that time that also existed in the habitable zone
Quotes from one of the scientists involved in the discovery
“Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent” “I have almost no doubt about it.”
It was phrased unfortunately, and the media have jumped on it, of course
This led to many headline grabbing stories, concepts of alien worlds and a J@N episode
The 581d and 581g Controversy
Both 581d and 581g were considered to be in the “habitable” region around the dwarf star they orbited
About two weeks after the discovery, another team said it could not find indications
Two years later another research team saying that analysis of an “extended dataset” from HARPS did show Gliese 581g
A press release at the time from the Planetary Habitability Laboratory the discovery would continue to be controversial
An Ending to the Story of 581d and 581g?
As of this week both 581d and 581g are crossed off
A new study shows that the two potentially habitable planets in the Gliese 581 system are just false signals arising out of the star’s activity and rotation
The uncertainty arises from the delicacy of looking for signals of small planets around much larger stars
Astronomers typically find planets through watching them pass across the face of a star, or measuring the tug that they exert on their parent star during their orbit
Researchers now say that only three planets exist around this star.
Further Reading / In the News
A Brief History Of Gliese 581d and 581g, The Planets That May Not Be | UniverseToday.com
Could Chance for Life on Gliese 581g Actually Be “100%”? | UniverseToday.com
Controversial clues of two ‘Goldilocks planets’ that might support life are proven false | ScienceDaily

— NEWS BYTE —

Research on Reversing Type 1 Diabetes

Investigators at the University of Cincinnati (UC) have found a therapy that reverses new onset Type 1 diabetes in mouse models and may advance efforts in combating the disease among humans.
Type 1 Diabetes
In Type 1 diabetes, the body does not produce sufficient insulin, which is central to glucose metabolism: without insulin, blood glucose rises
Type 1 diabetes is usually diagnosed in children and young adults and affects about 5 percent of all people with diabetes
There is no cure for Type 1 diabetes though it can be controlled with insulin therapy
Immune System
In Type 1 diabetes, autoimmunity causes the body’s T-cells to attack its insulin-producing beta cells.
There are two parts to the immune system: the innate immune system, which we are born with and attempts to fight infection straight away
And the adaptive immune system, which takes time to mount a response that is more specific to the particular pathogen
The innate immune system includes a group of cells known as dendritic cells that send messages to the adaptive immune system
Previous studies have already established that non-obese diabetic mice have faulty innate immune cells, and that this could be partly due to a defect in TLR4, which many suspect helps to prevent type 1 diabetes when it functions normally
Treatment
By using an antibody to stimulate a specific molecule in the innate immune system the researchers can reverse, with a high rate of success, new onset diabetes in mice that have already developed the symptoms of diabetes
The cause of this reversal is a preservation of the endocrine pancreatic beta cells that produce insulin
These cells are preserved from the autoimmune attack which is the hallmark of Type 1 diabetes
This approach differs from most in combating Type 1 diabetes because his team’s therapies in mice do not directly interact with T-cells
Treatment of autoimmunity has often been directed at suppressing an over-zealous adaptive immune response by eliminating autoreactive T-cells
There are two arms of the immune system, this treatment is targeting a different part of the immune system
The innate system tends to have a stereotypical response. this new research is targeting a receptor that is found mostly on the innate immune cells, such as dendritic cells.
The Future
The key to reversing Type 1 diabetes in mice, is catching the disease at its onset, which is typically within a very short time window
The time frame would be longer in humans, but it is still a relatively short time from new onset to end-stage Type 1 diabetes
While the TLR4 pathway in humans is similar to that of mice, there are some differences, so further study is required to see if the treatment will work in humans.
There is also a chance, if the therapy works in humans, that it will do so with an agonistic anti-TLR4 agent that is already approved, or under development
Further Reading / In the News
Reversal of type 1 diabetes in mice may eventually help humans | MedicalXPress.com
Type 1 diabetes ‘reversed’ in mice | MedicalNewsToday.com

— TWO-BYTE NEWS —

A New Earth-Like Exoplanet

A potentially habitable Earth-like planet that is only 16 light years away has been discovered
Discovery
The planet was discovered from its gravitational pull on its parent star, which causes the star to wobble slightly
This team had previously found, in 2009, that the star has a cold Jupiter-like planet with a near-circular orbit of about nine years, called Gliese GJ b.
“Earth-Like” Planet
The “super-Earth” planet, GJ 832 c, takes 16 days to orbit its red-dwarf star and has a mass at least five times that of Earth.
It receives about the same average stellar energy as Earth does, because red dwarfs shine more dimly than our Sun, and may have similar temperatures to our planet
These characteristics put it among the top three most Earth-like planets, according to the Earth Similarity Index developed by scientists at the University of Puerto Rica in Arecibo
Possible Atmosphere
The research group says that if the planet has a similar atmosphere to Earth it may be possible for life to survive, although seasonal shifts would be extreme
“However, given the large mass of the planet, it seems likely that it would possess a massive atmosphere, which may well render the planet inhospitable” | Head of UNSW’s Exoplanetary Science research group, Professor Chris Tinney
“A denser atmosphere would trap heat and could make it more like a super-Venus and too hot for life,” | Head of UNSW’s Exoplanetary Science research group, Professor Chris Tinney
Further Reading / In the News
Potentially habitable Earth-like planet discovered; May have similar temperatures to our planet | ScienceDaily

— SPACECRAFT UPDATE—

Opportunity Rover

Opportunity rover has reached a long sought after region of aluminum-rich clay mineral outcrops at a new Endeavour where ancient water once flowed billions of year ago.
The crater ridge is now “named ‘Pillinger Point’ after Colin Pillinger the Principal Investigator for the [British] Beagle 2 Mars lander
The Beagle 2 lander was built to search for signs of life on Mars
Opportunity’s Road Trip
The new photo mosaic above captured by Opportunity peering out from ‘Pillinger Point’ ridge on June 5, 2014 (Sol 3684) and showing a panoramic view around the eroded mountain ridge and into vast Endeavour crater
The crater spans 14 miles (22 kilometers) in diameter
For the past several months, the six wheeled robot has been trekking southwards from Solander towards the exposures of aluminum-rich clays
The rover mission scientists ultimate goal is travel even further south to ‘Cape Tribulation’ which holds a motherlode of the ‘phyllosilicate’ clay minerals
“The idea is to characterize the outcrops as we go and then once we reach the valley travel quickly to Cape Tribulation and the smectite valley, which is still ~2 km to the south of the present rover location,” | Prof. Ray Arvidson, Deputy Principal Investigator for the rover
Of Note
June 16 marked the 3696th Sol or Martian Day. Over 193,400 images have been taken during the 24.51 miles (39.44 kilometers) since touchdown on Jan. 24, 2004
Further Reading / In the News
Opportunity Peers Out from ‘Pillinger Point’ – Honoring British Beagle 2 Mars Scientist Where Ancient Water Flowed | UniverseToday.com

India’s Mars Orbiter Mission

Last Time on SciByte …
SciByte 111 | Memories & International Spacecraft (December 3,
2013)
SciByte 109 | ‘Earth-Like’ Planets & Sharks (November 12, 2013)
SciByte 107 | Dinosaurs & Satellites (October 29, 2013)
The Low Down
Mars Orbiter Mission or MOM, has now celebrated 100 days and 100 million kilometers out from Mars on June 16, until the crucial Mars Orbital Insertion (MOI) engine firing
Mars Orbiter Mission or MOM
India’s MOM probe will study the atmosphere and sniff for signals of methane.
MOM was designed and developed by the Indian Space Research Organisation (ISRO) at a cost of $69 Million and marks India’s maiden foray into interplanetary flight
The probe has flown about 70% of the way to Mars, traveling about 466 million kilometers out of a total of 680 million kilometers (400 million miles) overall, with about 95 days to go.
One way radio signals to Earth take approximately 340 seconds
ISRO reports the spacecraft and its five science instruments are healthy. It is being continuously monitored by the Indian Deep Space Network (IDSN) and NASA JPL’s Deep Space Network (DSN).
Trajectory Correction Maneuvers (TMSs)
Before reaching Mars, mission navigators must keep the craft on course from Earth to Mars through a series of in flight Trajectory Correction Maneuvers (TMSs).
The second TCM was just successfully performed on June 11 by firing the spacecraft’s 22 Newton thrusters for a duration of 16 seconds
TCM-1 was conducted on December 11, 2013 by firing the 22 Newton Thrusters for 40.5 seconds
Two additional TCM firings are planned in August and September 2014.
Indian Space Research Organization and NASA
Although they were developed independently and have different suites of scientific instruments, the MAVEN and MOM science teams will “work together” to unlock the secrets of Mars atmosphere and climate history, MAVEN’s top scientist
Working together, MOM and MAVEN will revolutionize our understanding of Mars atmosphere, dramatic climatic history and potential for habitability
“We have had some discussions with their science team, and there are some overlapping objectives,” “At the point where we [MAVEN and MOM] are both in orbit collecting data we do plan to collaborate and work together with the data jointly,” | MAVEN’s principal Investigator
Further Reading / In the News
India’s 1st Mars Mission Celebrates 100 Days and 100 Million Kilometers from Mars Orbit Insertion Firing – Cruising Right behind NASA’s MAVEN | UniverseToday.com

ISEE3 Reboot Project

— VIEWER FEEDBACK —

Titans Salty Ocean

Twitter | Kenny MacLeod ‏@siabost9deas
@JB_Mars_Base “Ocean on Saturn moon could be as salty as the Dead Sea” https://phys.org/news/2014-07-ocean-saturn-moon-salty-dead.html … #Cassini #Space #Titan #SaltySea
The Low Down
Scientists analyzing data from NASA’s Cassini mission have firm evidence the ocean inside Saturn’s largest moon, Titan, might be as salty as the Earth’s Dead Sea.
The new results come from a study of gravity and topography data collected during Cassini’s repeated flybys of Titan during the past 10 years
Salty Ocean or Brine
Researchers found that a relatively high density was required for Titan’s ocean in order to explain the gravity data
This indicates the ocean is probably an extremely salty brine of water mixed with dissolved salts likely composed of sulfur, sodium and potassium
The density indicated for this brine would give the ocean a salt content roughly equal to the saltiest bodies of water on Earth
“Knowing this may change the way we view this ocean as a possible abode for present-day life, but conditions might have been very different there in the past.” | Giuseppe Mitri of the University of Nantes in France
Icy Shell / Crust
Using the Cassini data, researchers presented a model structure for Titan, resulting in an improved understanding of the structure of the moon’s outer ice shell
The additional findings support previous indications the moon’s icy shell is rigid and in the process of freezing solid
Cassini data also indicate the thickness of Titan’s ice crust varies slightly from place to place.
The researchers said this can best be explained if the moon’s outer shell is stiff, as would be the case if the ocean were slowly crystallizing, and turning to ice.
Methane
A further consequence of a rigid ice shell, according to the study, is any outgassing of methane into Titan’s atmosphere must happen at scattered “hot spots”- like the hot spot on Earth that gave rise to the Hawaiian Island chain
Titan’s methane does not appear to result from convection or plate tectonics recycling its ice shell.
How methane gets into the moon’s atmosphere has long been of great interest to researchers, as molecules of this gas are broken apart by sunlight on short geological timescales
Titan’s present atmosphere contains about five percent methane. This means some process, thought to be geological in nature, must be replenishing the gas
“Our work suggests looking for signs of methane outgassing will be difficult with Cassini, and may require a future mission that can find localized methane sources,” said Jonathan Lunine, a scientist on the Cassini mission at Cornell University, Ithaca, New York
Further Reading / In the News
Ocean on Saturn moon could be as salty as the Dead Sea | Phys.org

— CURIOSITY UPDATE —

Driving Test Course
Curiosity rover has what is often referred to as a stunt double here on Earth, called ‘Scarecrow,’ that engineers use to test drive on different types of terrain
Scarecrow has a full-size version of Curiosity’s wheels and other driving equipment, but doesn’t have the “brains.”
Engineers have been scouring the Dumont Dunes area and look for the best spot to practice driving over dunes like those Curiosity may drive over on Mars
Recently engineers created a course of sand ripples for the Scarecrow rover to drive over to test the rover’s driving skills on soft sand ripples
On Mars, the Curiosity rover may cross similar sand ripples on its way to Mount Sharp
Another Travelling Milestone
After traversing 82 meters on June 27, 2014, Sol 672, the rover stopped because it determined that it was slipping too much
The rover automatically stopped when it encountered soft sand and sensed that it wasn’t making enough progress
“Coincidentally, the rover stopped right on the landing ellipse, a major mission milestone” | Mission scientist Ken Herkenhoff
Mission Info
Curiosity still has about another 2.4 miles (3.9 kilometers) to go to reach the entry way at a gap in the dunes at the foothills of Mount Sharp sometime later this year
To date, Curiosity’s odometer totals over 5.1 miles (8.4 kilometers) since landing inside Gale Crater on Mars in August 2012. She has taken over 162,000 images
Multimedia
YouTube Curiosity Rover Report JPLnews
Image Galleries at JPL and Curiosity Mulimedia
Social Media
Curiosity Rover @MarsCuriosity
Further Reading / In the News
Trekking Mars – Curiosity Roves Outside Landing Ellipse! | UniverseToday.com
‘Scarecrow’ Rover Goes Off-Roading in Dumont Dunes – Mars Science Laboratory | mars.jpl.nasa.gov

SCIENCE CALENDAR

Looking back

July 14, 1965 : 49 years ago : First Close-Up Photo of Mars : The Mariner 4 satellite sent a transmission of the first close-up photograph of Mars. It consisting of 8.3 dots per second of varying degrees of darkness. The transmission lasted for 8.5 hours and depicted the regions on Mars known as Cebrenia, Arcadia, and Amazonis. The satellite was 134 million miles away from earth and 10,500 miles from Mars. The 574-pound spacecraft had been launched at 9:22am on 28 Nov 1964, from Cape Canaveral, FL, by a two-stage Atlas-Agena D rocket. In addition to its camera with digital tape recorder (about 20 pictures), it carried instruments for studying cosmic dust, solar plasma, trapped radiation, cosmic rays, magnetic fields, radio occultation and celestial mechanics

Looking up this week

Keep an eye out for …
Fri, July 11 | At dusk you can see Mars and Spica in the SW sky just under 2* apart [1* is the width of your pinky held at arms length]
Sat, July 12 | Full Moon
Sun, July 13 | At dusk Mars and Spica are now just 1.3* apart
Planets
Mercury | Sunrise | low in the glow of sunrise to the lower left of Venus
Venus | Dawn | Low in the E
Mars | Dusk | High in the SW at dusk with Spica, a little fainter, closing in on it each day reaching their closest point on Sunday
Jupiter is lost in the sunset
Saturn | Late Twilight | Highest in the S
Further Reading and Resources
Sky&Telescope
SpaceWeather.com
StarDate.org
For the Southern hemisphere: SpaceInfo.com.au
Constellations of the Southern Hemisphere : astronomyonline.org
Royal Astronomical Society of New Zealand : rasnz.org.nz
AstronomyNow
HeavensAbove