Latest Posts

Proxima Centauri b: Have we just found Earth’s cousin right on our doorstep?

What began as a tantalizing rumor has just become an astonishing fact. Today a group of thirty-one scientists, led by Guillem Anglada-Escude at the Queen Mary University of London, UK, announced the discovery of a terrestrial exoplanet orbiting Proxima Centauri. The discovery of this planet, Proxima Centauri b, is a huge breakthrough not just for astronomers but for all of us. Here’s why.

This artist’s impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface. Credit: ESO/M. Kornmesser

This artist’s impression shows a view of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System. The double star Alpha Centauri AB also appears in the image to the upper-right of Proxima itself. Proxima b is a little more massive than the Earth and orbits in the habitable zone around Proxima Centauri, where the temperature is suitable for liquid water to exist on its surface.
Credit: ESO/M. Kornmesser

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Calling for a Better World – Remember to Vote

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In English

Another attack this month, this time in Nice in the middle of the 14 July celebrations. First, the obvious: this attack, which targeted people and families watching fireworks, was despicable and inhuman. Of course, I send my thoughts to the victims and their families as well as to my colleagues and friends who live in Nice. But I am tired of being an impotent witness to this outbreak of violence everywhere in the world, and I absolutely refuse to remain silent. Like many people, I feel like I’m living a nightmare, in a polarized world in which a tiny minority of violent sociopaths want us to embrace ideas from another time whatever the cost to us, our loved ones, our values, and our dignity as human beings. I hope that this stops and that we find a solution and learn, once and forever more, to live together in peace. But we are living in a very difficult time and we must prepare for many setbacks and tragedies.

The events in Nice also make it imperative that we learn certain key lessons. We, the citizens of free nations going about our daily business, are paying a huge price for wars launched in the first decade of this century by radical and ignorant politicians who manipulated their nations into engaging in a war without end, a war that accomplishes nothing except awakening extremism and hatred in the minds of the weak, the ignorant, and the alienated. (more…)

The Triple Asteroid (87) Sylvia

Another beautiful simulation of the triple asteroid system (87) Sylvia and its two moons Romulus and Remus made in collaboration with the California Academy of Sciences.

Screen Shot 2016-06-14 at 11.48.50 PM(87) Sylvia was discovered in 1866 by N.R. Pogson, a British astronomer located in Madras, India. This main-belt asteroid is large with a diameter of ~150 km. That’s all we knew until recently.

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Flying through the binary trojan asteroid system (617) Patroclus

Another day, another video!

This time I am posting a video of the binary L5 Trojan Asteroid (617) Patroclus-Menoetius. In collaboration, with the team at the California Academy of Sciences, we have created a model of this interesting binary asteroid system which shares its orbit with Jupiter.

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Visiting the L4 Trojan Asteroid (624) Hektor

I finally started uploading some of the animations of the talk that I gave last month at the California Academy of Sciences. Today let’s watch (624) Hektor, the binary and bilobed largest Jupiter-Trojan asteroids. This is a puzzling multiple asteroid system with a lot of mysteries (eccentric and inclined orbit of the moon, complex shape and structure for the primary, …). 

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Our study based on AO observations collected over 8 years was published in 2014. The conclusion of our work is that 624 Hektor is probably a captured Kuiper-belt object and the moon formed a long time ago from the slow velocity encounter of the components.

The Largest Jupiter Trojan: 624 Hektor and its moon from Franck Marchis on Vimeo.

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Gravitational wave detection rumors may end on Feb 11

It is official. NSF, together with scientists from Caltech, MIT and the LIGO collaboration will give an update on their effort to detect gravitational waves.

What is LIGO? Check out this article published in Arstechnica by Eric Berger.

I am not going to speculate on the announcement and will simply wait for it. Joe Giaime a California Institute of Technology physicist who manages the lab and also a professor at Louisiana State University was pretty clear in the Arstechnica interview about the way this group works: “We’re really kind of old school,” he said. “We analyze our data. If there’s anything interesting we write it up in papers. We send the papers to the journals. If and only if there’s an interesting discovery that passes muster, and it has been accepted for publication by a journal, then we blab about it. Anything before that, you’re not going to get anything out of me.”

So if they indeed have detected those gravitational waves, we will also get a paper.

Computer simulation of a black hole collision. When two black holes merge into one, enormous amounts of energy are released in the form of gravitational waves.

Computer simulation of a black hole collision. When two black holes merge into one, enormous amounts of energy are released in the form of gravitational waves.

Below the official announcement.

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How to explain the inconceivable

PeaceForParis by the artist Jean Jullien

I am often asked to comment on what happened in Paris last December since I have both French and American citizenships and I live in the US. Like a lot of my compatriotes, it has been difficult to watch those events unfold on Friday afternoon December 13 (I was working at George Mason University in DC ). Since then, he has been also impossible to rationalize what really happened and to give a sense on those horrific events. Today I listened to “Geopolitique”, a short program aired on France Inter which described events and their consequences in the geopolitical scale. Bernard Guetta summarized very well what are my thoughts on the Paris events and its consequences, so I decided to share with you  an English translation which has been freely adapted. The French version   “Comment expliquer l’inconcevable” is available on the France Inter web site.

PeaceForParis by the artist Jean Jullien

PeaceForParis by the artist Jean Jullien

The perpetrators of the most recent murders have no excuse whatsoever, especially not one that seeks to blame the societies they live in. Nor, for that matter, did Mohamed Merah before them, or the killers of November 13, or the killers of January 7 in Paris. They were certainly not mentally ill and they certainly were responsible for their actions — and cannot claim that the challenges of integrating into a new society make them the bloodthirsty monsters they became. (more…)

AGU 2015 session: Direct Imaging of Habitable Exoplanets: Progress and Future

Artist concept of the planetary system Kepler 62. Image credit: Danielle Futselaar - SETI Institute

Artist concept of the planetary system Kepler 62. Image credit: Danielle Futselaar – SETI Institute

Join us tomorrow at the AGU Fall Meeting for a session on direct imaging of habitable exoplanets that I organized with my colleagues Ramses Ramirez from Cornell University and David Black.

This session consists in a discussion on the potential of new and future facilities and modeling efforts designed to detect, image and characterize habitable exoplanets, studying their formation, evolution and also the existence of possible biospheres. Topics to be covered in this session include signs of exoplanet habitability and global biosignatures that can be sought with upcoming instrumentation; instrument requirements and technologies to detect these markers; strategies for target selection and prioritization; and impacts of planetary system properties, ground-based and space telescope architectures, and impacts of instrument capabilities on the yield of potentially inhabited exoplanets.

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Thoughts on GPI

In a major breakthrough for exoplanet discovery and exploration, the Gemini Planet Imager (GPI) is proving to be one of most powerful and effective instruments ever invented for directly imaging planets in orbit around other stars.

An artistic conception of the Jupiter-like exoplanet, 51 Eri b, seen in the near-infrared light that shows the hot layers deep in its atmosphere glowing through clouds. Because of its young age, this young cousin of our own Jupiter is still hot and  carries information on the way it was formed 20 million years ago.  credits: Danielle Futselaar & Franck Marchis, SETI Institute

An artistic conception of the Jupiter-like exoplanet, 51 Eri b, seen in the near-infrared light that shows the hot layers deep in its atmosphere glowing through clouds. Because of its young age, this young cousin of our own Jupiter is still hot and carries information on the way it was formed 20 million years ago.
credits: Danielle Futselaar & Franck Marchis, SETI Institute

The behind-the-scenes story of this project sheds light on the complexities and challenges of designing and building a truly game-changing instrument. We started work more than thirteen years ago under the leadership of Bruce Macintosh and the auspices of the Center for Adaptive Optics. At that time, a number of scientists, most from California and Canada, met to discuss building a groundbreaking adaptive optics (AO) system powerful enough to confront — and overcome — the challenging of directly collecting photons from young Jupiter-like exoplanets. The discovery of 51 Eri b, which was announced last August, is the culmination of that effort. 

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Happy New Year to the Planet!

I decided to do something new to start the New Year. I translated a podcast from a program called Geopolitics on France Inter written by Anthony Bellanger. You can listen to the original French version here.

I like the text since it is quite optimistic and it summarizes the progresses that we have made over the past 50 years. The world is not perfect yet, but it is indeed a better place.

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Are there any reasons to wish people a Happy New Year 2015?


I believe there are many and would like to explain why.

First: our health. Never have so many people all over the world been so healthy and well cared for.

It may seem strange to say that when nearly 8,000 people have died of Ebola in West Africa in recent months, and when the epidemic is far from defeated—yet it’s true.

Over the last half century , the infant mortality rate has fallen by two-thirds and the average human lifespan has increased by twenty years and continues to grow. Better yet, the difference in life expectancy between rich and poor countries is narrowing year by year.

Thanks to modern medicine, diseases that decimated entire populations throughout history are almost eradicated. The number of polio cases, for example, has fallen by 99% since 1988.

Between 2000 and 2015, the number of global malaria cases has dropped in half thanks to a global mobilization against the disease. Even AIDS, which appeared only 30 years ago, is now tested for and treated all over the world.

What about hunger and education?

Here, too, things are looking up. Hunger around the world declines annually. Since the early 90s — only 25 ago! — the percentage of undernourished people around the world has fallen by half.

The great famines that killed tens of thousands of people in the 1980s — in Ethiopia, for example —have disappeared. The world is better organized than ever and extremely efficient at delivering emergency medical and food aid when and where it is needed.

On the education front, results are even more impressive: In only 10 years, school enrollment for boys and girls has increased from 84 to 89% in primary grades and 60 to 73% in secondary grades. Around the world, three out of four children go to school until they are at least 14 years old!

We see similar improvements in the area of extreme poverty, which has fallen by 50 percent since 1990. This is unheard of in human history.

What is the source of this improvement?

We all are! Despite what we may hear or say, international institutions — the UN, NGOs and many others —work effectively: they treat, train, vaccinate, feed and intervene anywhere in the world where they are needed.

Even freedom is rising: in the last half century, the number of democratic states has tripled, and half the world’s population now lives under this type of government which — though often imperfect — is a unique achievement in human history.

So yes, one may wish people a Happy New Year, knowing that there will be wars, massacres, and many other disasters but also knowing that we have never been better educated, cared for and nurtured than we are in 2015.