This week space fans, we will begin somewhat differently, with me answering one of your burning questions: namely, how you find these pesky exoplanets? Now this is a big question, so this week we’ll start with the current most popular method:
TRANSIT PHOTOMETRY
There are a number of ways to spot an exoplanet, and there are missions to find them, notably the Kepler telescope’s amazing findings which are still yielding results even now as scientists trawl through the vast amounts of data it has produced, in particular the so called Earth 2.0. Kepler sadly became damaged in 2013, however the K2 mission is now underway which utilizes the disabled spacecraft’s remaining capabilities.
Image credit: NASA
K2’s image precision will not be as good as it was, but will still be useful nonetheless and will also look at a larger area of sky. The upcoming TESS mission will also be looking for planetary transits
When a planet passes in front of a star as viewed from Earth, the event is called a “transit.” On Earth, we can observe an occasional Venus or Mercury transit. These events are seen as a small black dot creeping across the Sun—Venus or Mercury blocks sunlight as the planet moves between the Sun and us, very much like an eclipse, only much much smaller. If you stumble over the word ”occultation” in you Google wanderings, it’s the same thing! In fact, these transits in our own Solar system have been invaluable to fine-tune the maths and the methods used in missions such as this. Kepler finds planets by looking for tiny dips in the brightness of a star when a planet crosses in front of it, or transits the star.
2012’s Venus transit
The dimming of a star during transit directly reflects the size ratio between the star and the planet; A small planet transiting a large star will create only a slight dimming, while a large planet transiting a small star will have a more noticeable effect, hence why we keep finding these pesky ‘vagrant Jupiters’ some of you disapprove of. The size of the host star can be known with considerable accuracy from its spectrum, and photometry therefore gives astronomers a good estimate of the orbiting planet’s size, but not its mass. The downside of this method is that if its not transiting, we can’t see it. Another drawback is that we can only detect it at that short time its crossing in front of its star, so if it has a long orbital period of say, months or even years, then its highly unlikely we will find it.
Photometry is however an excellent complement to the spectroscopic, or radial velocity method, which provides an estimate of a planet’s mass, but not its size. Using both methods, combining mass and size, scientists can calculate the planet’s density, an important step towards assessing its composition. We will tackle the spectroscopic method another time.
Now for the space news!
KEPLER 2 IN EMERGENCY MODE
On Aptil 7, the Kepler mission team made a recovery. EM mode is when the craft is in its lowest mode of operation and uses the most fuel. It’s important to rectify this as the next goal for the K2 mission is to turn it around to point at the centre of the galaxy in order to seek out yet more new worlds. Previous contact was on April 4 when all seemed well.
Kepler completed its prime mission in 2012, detecting nearly 5,000 exoplanets, of which more than 1,000 have been confirmed. In 2014, the Kepler spacecraft began a new mission called K2. In this extended mission, K2 continues the search for exoplanets while introducing new research opportunities to study young stars, supernovae, and many other astronomical objects.
As of April 11, the mission engineers have rescued the craft:
“The anomalous EM event is the first that the Kepler spacecraft has encountered during its seven years in space. Mission operations at NASA’s Ames Research Center in California’s Silicon Valley, Ball Aerospace and the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder remain vigilant.
It was the quick response and determination of the engineers throughout the weekend that led to the recovery. We are deeply appreciative of their efforts, and for the outpouring of support from the mission’s fans and followers from around the world. We also recognize the tremendous support from NASA’s Deep Space Network, managed by the Jet Propulsion Laboratory in Pasadena, California, and to NASA’s other missions that surrendered their scheduled telemetry links in order to provide us with the resources needed to protect the Kepler spacecraft.”
Phew!
SPACEX SUCCESSFULLY LANDS AT SEA
I don’t mind telling I did in fact jump up and down in nerdy excitement. Carrying an important payload of an expandable lab module as well as general supplies, the SpaceX Dragon rocket launched at 4:43pm EDT April 8 from Cape Canaveral in Florida.
“The cargo will allow investigators to use microgravity conditions to test the viability of expandable space habitats, assess the impact of antibodies on muscle wasting, use protein crystal growth to aid the design of new disease-fighting drugs and investigate how microbes could affect the health of the crew and their equipment over a long duration mission,” said NASA Deputy Administrator Dava Newman.
As interesting as that is, what everyone was REALLY hyped about was ‘Will there be another rapid unscheduled disassembly?’. This time however, everything went to plan and the rocket landed safely on the amusingly titled ‘Of Course I Still Love you!’ There is a video of the whole thing I strongly urge you to watch.
PROJECT BREAKTHROUGH STARSHOT TO AIM FOR ALPHA CENTAURI
Billionaire Yuri Milner, with the backing of Stephen Hawking, has pledged $100,000,000 to get a spacecraft to Alpha Centauri in just 20 years. We’re not talking about manned spaceships – these little guys can fit in your hand and are known as ”wafersats”, weighing just a few grams and packing the brains of a smartphone. The hope is to sent out thousands of them to probe the system and send back information.
“We have done some recent research with some of the best minds in different areas, and to my surprise I have concluded it can be done within a generation,” says Milner. But the ambitious project, dubbed Breakthrough Starshot, is likely to raise eyebrows amongst the scientific community.
As to how they’ll get there? The intention is to use meter-wide solar sails using photons to propel them. This only provides a small amount of thrust, so the plan is to use lasers to accelerate them to 20% of lightspeed, which would allow them to cross the 4 lightyear distance to Alpha Centauri in 20 years.
The technology required to do this doesn’t yet exist, but Milner is confident his team can develop it. “We have researched about 20 technical challenges, and we believe that none of those is insurmountable,” he says. “There is no physical law that contradicts this particular model.”
“The human story is one of great leaps,” Milner said. “Today we are preparing for the next great leap – to the stars.” And Professor Hawking said: “Earth is a wonderful place, but it might not last forever. Sooner or later we must look to the stars. Breakthrough Starshot is a very exciting first step on that journey.”
It is hoped that continuing development of nanotechnology and microchips will ensure that miniaturization will keep down the launch and fuel costs to get these tiny craft into space.
“We hope to have good answers to the key challenges in about 10 years. At that time we hope to have assembled a coalition of high net-worth individuals to fund the full-scale project and begin work on what will likely be a 10 year or more construction effort,” Worden told the Guardian. “The key challenge is that the final interstellar system is affordable – by that we mean its final cost is comparable to other large scientific endeavours such as the Cern accelerator.”
He added: “We would welcome participation by governments, national and international organisations and space agencies. Indeed, we have already discussed our plans with several space agencies around the world.”
Speaking at the project’s launch on Tuesday, Hawking said transcending our limits was what made humans unique. “Gravity pins us to the ground but I just flew to America. I lost my voice but I can still speak thanks to my voice synthesiser. How do we transcend these limits? With our minds and our machines.
“The limit that confronts us now is the great void between us and the stars. But now we can transcend it, with light beams, light sails, and the lightest spacecraft ever built we can launch a mission to Alpha Centauri within a generation. Today we commit to this next great leap into the cosmos, because we are human and our nature is to fly.”
This is a very ambitious project that I truly would love to see succeed.
This article originally appeared on TheMittani.com, written by Feiryred.
