Search This Blog
Friday, 17 March 2017
Sunday, 26 February 2017
7 Earth-Size Planets Orbit Dwarf Star, NASA and European Astronomers Say
These new Earth-size planets orbit a dwarf star named Trappist-1 about 40 light years from Earth. Some of them could have water on their surfaces.
Not just one, but seven Earth-size
planets that could potentially harbor life have been identified
orbiting a tiny star not too far away, offering the first realistic
opportunity to search for signs of alien life outside the solar system.
The
planets orbit a dwarf star named Trappist-1, about 40 light-years, or
235 trillion miles, from Earth. That is quite close in cosmic terms, and
by happy accident, the orientation of the orbits of the seven planets
allows them to be studied in great detail.
One
or more of the exoplanets in this new system could be at the right
temperature to be awash in oceans of water, astronomers said, based on
the distance of the planets from the dwarf star.
“This
is the first time so many planets of this kind are found around the
same star,” Michael Gillon, an astronomer at the University of Liege in
Belgium and the leader of an international team that has been observing
Trappist-1, said during a telephone news conference organized by the
journal Nature, which published
Scientists could even discover compelling evidence of aliens.
“I
think that we have made a crucial step toward finding if there is life
out there,” said Amaury H. M. J. Triaud, an astronomer at the University
of Cambridge in England and another member of the research team. “Here,
if life managed to thrive and releases gases similar to that we have on
Earth, then we will know.”
Cool
red dwarfs are the most common type of star, so astronomers are likely
to find more planetary systems like that around Trappist-1 in the coming
years.
“You
can just imagine how many worlds are out there that have a shot to
becoming a habitable ecosystem,” Thomas Zurbuchen, associate
administrator of NASA’s science mission directorate, said during a NASA
news conference on Wednesday. “Are we alone out there? We’re making a
step forward with this — a leap forward, in fact — towards answering
that question.”
Telescopes on the ground now and the Hubble Space Telescope in orbit will be able to discern some of the molecules in the planetary atmospheres. The James Webb Space Telescope, scheduled to launch next year, will peer at the infrared wavelengths of light, ideal for studying Trappist-1.
Comparisons among the different conditions of the seven will also be revealing.
“The Trappist-1 planets make the search for life in the galaxy imminent,” said Sara Seager,
an astronomer at the Massachusetts Institute of Technology who was not a
member of the research team. “For the first time ever, we don’t have to
speculate. We just have to wait and then make very careful observations
and see what is in the atmospheres of the Trappist planets.”
Even if the planets all turn out to be lifeless, scientists will have learned more about what keeps life from flourishing.
Astronomers
always knew other stars must have planets, but until a couple of
decades ago, they had not been able to spot them. Now they have
confirmed more than 3,400, according to the Open Exoplanet Catalog. (An exoplanet is a planet around a star other than the sun.)
The
authors of the Nature paper include Didier Queloz, one of the
astronomers who discovered in 1995 the first known exoplanet around a
sunlike star.
While
the Trappist planets are about the size of Earth — give or take 25
percent in diameter — the star is very different from our sun.
Trappist-1,
named after a robotic telescope in the Atacama Desert of Chile that the
astronomers initially used to study the star, is what astronomers call
an “ultracool dwarf,” with only one-twelfth the mass of the sun and a
surface temperature of 4,150 degrees Fahrenheit, much cooler than the
10,000 degrees radiating from the sun. Trappist is a shortening of
Transiting Planets and Planetesimals Small Telescope.
During
the NASA news conference, Dr. Gillon gave a simple analogy: If our sun
were the size of a basketball, Trappist-1 would be a golf ball.
Until
the last few years, scientists looking for life elsewhere in the galaxy
have focused on finding Earth-size planets around sun-like stars. But
it is hard to pick out the light of a planet from the glare of a bright
star. Small dim dwarfs are much easier to study.
Last year, astronomers announced the discovery of an Earth-size planet around Proxima Centauri,
the closest star at 4.24 light-years away. That discovery was made
using a different technique that does not allow for study of the
atmosphere.

Trappist-1
periodically dimmed noticeably, indicating that a planet might be
passing in front of the star, blocking part of the light. From the shape
of the dips, the astronomers calculate the size of the planet.
Trappist-1’s light dipped so many times that the astronomers concluded, in research reported last year,
that there were at least three planets around the star. Telescopes from
around the world then also observed Trappist-1, as did the Spitzer Space Telescope of NASA.
Spitzer
observed Trappist-1 nearly around the clock for 20 days, capturing 34
transits. Together with the ground observations, it let the scientists
calculate not three planets, but seven. The planets are too small and
too close to the star to be photographed directly.
All
seven are very close to the dwarf star, circling more quickly than the
planets in our solar system. The innermost completes an orbit in just
1.5 days. The farthest one completes an orbit in about 20 days. That
makes the planetary system more like the moons of Jupiter than a larger
planetary system like our solar system.
“They form a very compact system,” Dr. Gillon said, “the planets being pulled close to each other and very close to the star.”
In
addition, the orbital periods of the inner six suggest that the planets
formed farther away from the star and then were all gradually pulled
inward, Dr. Gillon said.
Because
the planets are so close to a cool star, their surfaces could be at the
right temperatures to have water flow, considered one of the essential
ingredients for life.
The
fourth, fifth and sixth planets orbit in the star’s “habitable zone,”
where the planets could sport oceans. So far that is just speculation,
but by measuring which wavelengths of light are blocked by the planet,
scientists will be able to figure out what gases float in the
atmospheres of the seven planets.
So
far, they have confirmed for the two innermost planets that they are
not enveloped in hydrogen. That means they are rocky like Earth, ruling
out the possibility that they were mini-Neptune gas planets that are
prevalent around many other stars.
Because
the planets are so close to Trappist-1, they have quite likely become
“gravitationally locked” to the star, always with one side of the
planets facing the star, much as it is always the same side of Earth’s
moon facing Earth. That would mean one side would be warmer, but an
atmosphere would distribute heat, and the scientists said that would not
be an insurmountable obstacle for life.
For
a person standing on one of the planets, it would be a dim environment,
with perhaps only about one two-hundredth the light that we see from
the sun on Earth, Dr. Triaud said. (That would still be brighter than
the moon at night.) The star would be far bigger. On Trappist-1f, the
fifth planet, the star would be three times as wide as the sun seen from
Earth.
As for the color of the star, “we had a debate about that,” Dr. Triaud said.
Some
of the scientists expected a deep red, but with most of the star’s
light emitted at infrared wavelengths and out of view of human eyes,
perhaps a person would “see something more salmon-y,” Dr. Triaud said.
NASA released a poster illustrating what the sky of the fourth planet might look like.
If
observations reveal oxygen in a planet’s atmosphere, that could point
to photosynthesis of plants — although not conclusively. But oxygen
together with methane, ozone and carbon dioxide, particularly in certain
proportions, “would tell us that there is life with 99 percent
confidence,” Dr. Gillon said.
Astronomers
expect that a few decades of technological advances are needed before
similar observations can be made of Earthlike planets around larger,
brighter sunlike stars.
Dr. Triaud said that if there is life around Trappist-1, “then it’s good we didn’t wait too long.”
“If there isn’t, then we have learned something quite deep about where life can emerge,” he continued.
The
discovery might also mean that scientists who have been searching for
radio signals from alien civilizations might also have been searching in
the wrong places if most habitable planets orbit dwarfs, which live far
longer than larger stars like the sun.
The SETI Institute in Mountain View, Calif., is using the Allen Telescope Array,
a group of 42 radio dishes in California, to scrutinize 20,000 red
dwarfs. “This result is kind of a justification for that project,” said
Seth Shostak, an astronomer at the institute.
“If
you’re looking for complex biology — intelligent aliens that might take
a long time to evolve from pond scum — older could be better,” Dr.
Shostak said. “It seems a good bet that the majority of clever beings
populating the universe look up to see a dim, reddish sun hanging in
their sky. And at least they wouldn’t have to worry about sun block.”
Correction: February 22, 2017
An earlier version of this article named the wrong telescope
that is trained on the Trappist-1 dwarf star. It is the Spitzer Space
Telescope, not the Kepler. The article also misstated how many days it
takes for the planet farthest from Trappist-1 to orbit the star. It is
about 20 days, not 12.35.
Tuesday, 7 February 2017
Ex-secy Nurul Huda new CEC
Ex-secy Nurul Huda new CEC
President also appoints four election commissioners including one woman
Former secretary KM Nurul Huda has been chosen to lead the next Election Commission.
President Abdul Hamid appointed him chief election commissioner last
night in line with a constitutional provision, according to a gazette
notification issued around 10:00pm.
The president also appointed four election commissioners who include
one woman for the first time. They are Mahbub Talukder, former
additional secretary; Md Rafiqul Islam, ex-secretary; Begum Kabita
Khanam, former district and sessions judge; and Brig Gen (retd) Shahadat
Hossain Chowdhury.
The oath-taking ceremony of the new EC would take place today or tomorrow, said sources at the Bangabhaban.
In his immediate reaction, the newly appointed CEC said, "I am
grateful to the president for appointing me to this important
constitutional position. I will try my best to carry out the
responsibility impartially in line with the constitution."
Nurul Huda, a freedom fighter, told The Daily Star that he would
devise a work strategy for the commission after consulting his
colleagues.

"We will sit with the political parties because they are the most
important stakeholders," he said, seeking cooperation from all political
parties, civil society members as well as other stakeholders in
performing his duties.
Earlier, Cabinet Secretary Shafiul Alam said Nurul Huda's name was
not there in the proposals of the ruling Awami League and the BNP,
submitted to the six-member search committee for constituting the next
EC.
Of the commissioners, Mahbub's name was suggested by the BNP while
Kabita's name was proposed by the AL, he told reporters at the Cabinet
Division.
In the evening, the search panel met the president at the
Bangabhaban, and proposed the names of Nurul Huda and ex-cabinet
secretary Ali Imam Majumder for the CEC post.
Majumder was also recommended for the job in 2012 but the then president didn't pick him.
Born in 1948 in Patuakhali's Baufal, Nurul Huda completed his
schooling in Patuakhali. He obtained his graduation and master's in
Statistics from Dhaka University.
He also studied Public Administration and Advanced Studies at the
University of Manchester, and pursued further studies in the then Soviet
Union, he said.
Nurul Huda joined the 1971 Liberation War in Sector-9.
Sunday, 18 September 2016
People suffer in Paturia, Daulatdia tailbacks
People suffer in Paturia, Daulatdia tailbacks
Passengers
on the both ends of Paturia and Daulatdia ferry terminals are suffering
as they remain stuck in a tailback on Sunday, September 18, 2016. In
the photo, workers are putting sand-filled sacks on the banks of the
Padma River to save a ferry landing station in Paturia terminal from
erosion. Photo: Palash Khan
Star Online Report
Passenger busses remain stuck in a tailback at Paturia ferry terminal
on Sunday, September 18, 2016. Photo: Palash Khan Thousands of people
have been suffering on both ends of Paturia and Daulatdia ferry
terminals due to a tailback.
Ferry services at the terminals were hampered triggering a two-kilometre tailback as the number of landing stations at Daulatdia end was decreased due to river erosion.
Passengers of 21 south and south-western districts travelling to and fro have been facing serious problems including shortages food and toilet facilities at the ferry terminals.
Ferry services at the terminals were hampered triggering a two-kilometre tailback as the number of landing stations at Daulatdia end was decreased due to river erosion.
Passengers of 21 south and south-western districts travelling to and fro have been facing serious problems including shortages food and toilet facilities at the ferry terminals.

Passenger busses remain stuck in a tailback at Paturia ferry terminal on Sunday, September 18, 2016.
Two of the four landing stations of the Two of the four landing
stations of the Daulatdia terminal are in operation, our Manikganj
correspondent reports quoting Md Shafiqul Islam, manager (commerce) of
Bangladesh Inland Water Transport Corporation (BIWTC) at Daulatdia ferry
terminal.
The landing station no. 4 was closed at around 1:00am today as its approach road of Rajbari Roads and High ways damaged by the river erosion, he said.
The landing station no. 2 was suspended earlier due to the damage by the erosion, the BIWTC official added.
Abdus Sattar, manager (Marine), of Bangladesh Inland Water Transport Corporation (BIWTC) at Aricha office, said 13 of 19 ferries are in operation as six are being repaired.
Around five hundred vehicles were seen stranded at Daulatdia terminal under Goalunda upazila in Rajbari district today.
On the other end, a two-kilometre tailback was created at Paturia ferry terminal under Shivalaya upazila in Manikganj where Shyamal, a youth of Faridpur, said he was waiting for ferry at Paturia terminal for nearly three hours.
A driver of Eagle Paribahan said his vehicle was stranded at Paturia terminal for more than two and a half hour.
The landing station no. 4 was closed at around 1:00am today as its approach road of Rajbari Roads and High ways damaged by the river erosion, he said.
The landing station no. 2 was suspended earlier due to the damage by the erosion, the BIWTC official added.
Abdus Sattar, manager (Marine), of Bangladesh Inland Water Transport Corporation (BIWTC) at Aricha office, said 13 of 19 ferries are in operation as six are being repaired.
Around five hundred vehicles were seen stranded at Daulatdia terminal under Goalunda upazila in Rajbari district today.
On the other end, a two-kilometre tailback was created at Paturia ferry terminal under Shivalaya upazila in Manikganj where Shyamal, a youth of Faridpur, said he was waiting for ferry at Paturia terminal for nearly three hours.
A driver of Eagle Paribahan said his vehicle was stranded at Paturia terminal for more than two and a half hour.
Powerful Blast Injures at Least 29 in Manhattan; Second Device Found
A
powerful explosion caused by what the authorities believe was a
homemade bomb injured at least 29 people on a crowded sidewalk in the
bustling Chelsea neighborhood of Manhattan on Saturday night.
A
few hours later, the authorities found and removed what they described
as a second explosive device four blocks away, raising the possibility
that two bombs had been planted in the heart of the city.
Mayor
Bill de Blasio called the explosion — which occurred about 8:30 p.m. on
West 23rd Street — “an intentional act” but initially said there was no
connection to terrorism and no immediate claim of responsibility.
Police
officers swarmed Chelsea’s streets after the blast, which reverberated
across a city scarred by terrorism and vigilant about threats, just days
after the 15th anniversary of the Sept. 11 attacks.
“Whatever the cause,” Mr. de Blasio said, “New Yorkers will not be intimidated.”
As the authorities sought to identify what had caused the explosion, they described the second device as a pressure cooker resembling the one used in the deadly Boston Marathon
bombings in 2013, according to a police official, who spoke on the
condition of anonymity to discuss a continuing investigation.
It was unclear whether the blast on West 23rd Street had been caused by the same type of explosive.
In the immediate aftermath, the police shut down a swath of Manhattan
south of Midtown. The area from 14th Street to 32nd Street was closed
to traffic between Fifth and Eighth Avenues. But by 7 a.m., only 23rd
Street remained closed.
A
grim Mr. de Blasio, speaking at a news conference at the scene around
11:15 p.m., said “injuries are significant.” But for the moment, he
said, none of them were life-threatening.
Many
of the injuries were caused by shrapnel from the explosion, which
witnesses said seemed to have started inside a sidewalk Dumpster near
the Avenue of the Americas. Images of a twisted Dumpster in the middle
of West 23rd Street quickly proliferated on Twitter.
The
impact shattered windows, damaged cars and sent crowds running from the
scene at an hour when Chelsea, always a popular destination, was filled
with residents and tourists.
“It
was the biggest blast I ever would imagine, lights flashing, glass
shattering,” said a woman who was injured in the explosion.
The force of the explosion, she said, flung her into the air.
“It
happened so fast I was thrown up and landed down, I didn’t know where
it had come from,” said the woman, who would give only her first name,
Helena, as she hobbled out of Bellevue Hospital Center about 4 a.m.
after she was treated for injuries to her eye and legs. “I realized
there was blood streaming down my face, and I couldn’t see out of my
eye.”
Luke
McConnell, who was visiting from Colorado, was headed toward a
restaurant on West 27th Street when the blast occurred. “I felt it, like
a concussive wave, heading towards me.”
“Then
there was a cloud of white smoke that came from the left side of 23rd
Street near Sixth,” he said. “There was no fire, just smoke.”
Witnesses
said they could feel the explosion from several blocks away. Daniel
Yount, 34, said he was standing on the roof of a building at 25th Street
and the Avenue of the Americas with friends.
“We felt the shock waves go through our bodies,” he said.
It
was a startling scene, full of dark possibilities, for a city that
endured the attacks of Sept. 11, 2001, but has so far been spared the
kind of mayhem that has terrorized city after city around the world in
the 15 years since.
The
closest New York has come to an attack was in 2010, when the police
found a crude car bomb of propane, gasoline and fireworks inside a sport
utility vehicle in Times Square. Although the device had apparently
started to detonate, there was no explosion.
On Saturday night in Chelsea, the device found on West 27th Street also caused no harm.
Images
shared on social media and confirmed as authentic by a senior police
official showed a silver-colored piece of cookware with wires and a
cellphone attached.
The
official said the Police Department’s bomb squad was taking the device
to a department facility in the Bronx, where robots would inspect it.
Around
2:25 a.m., a Police Department truck towing a spherical chamber, which
contained the device, headed east on West 27th Street and turned up the
Avenue of the Americas. Several police officers who had spent the
evening on alert were visibly relieved, as one by one they let the few
residents who had been waiting all night beside the caution tape return
home.
It
was a cool Saturday night, and the businesses along West 23rd Street,
the busiest east-west thoroughfare in Chelsea, were teeming with
customers.
The
blast seemed to shake the entire block, smashing windows in a
five-story brownstone building and sending debris into the street, a law
enforcement official said.
The
sidewalk where the explosion occurred is in front of a nondescript
building wedged between a church and an apartment building.
Video
captured before the explosion shows a man crossing “the street in the
direction of where the device was found,” the same official said. But no
video had yet been obtained clearly showing anyone placing the device
in the spot where it detonated.
“We
don’t understand the target or the significance of it,” the police
official said. “It’s by a pile of Dumpsters on a random sidewalk.”
Marcello Begu, 58, was spinning pizzas at the nearby Ciao Bella Napoli restaurant when he heard the blast.
“I’ve never heard a noise like that in my life,” he said. “The ground was shaking. I was scared to go outside.”
In
Washington, the White House issued a brief statement saying that
President Obama had been briefed on the developing situation in New
York.
Both the Democratic and Republican presidential candidates broke from their campaign routines to address the issue.
Donald
J. Trump, in Colorado Springs, rushed to describe the explosion as a
bomb well before the authorities had made any determinations about what
had happened and while the situation was still in flux.
“I
must tell you that just before I got off the plane, a bomb went off in
New York and nobody knows exactly what’s going on,” he said. “But boy,
we are living in a time — we better get very tough, folks.”
The
Democratic nominee, Hillary Clinton, was informed of the episode after
she gave a speech at the Congressional Black Caucus Foundation’s annual
awards dinner, her campaign said.
She seemed to scold Mr. Trump for his quick assessment.
“I think it’s always wiser to wait until you have information before making conclusions,” Mrs. Clinton said.
Officials said the New York explosion was not connected to a blast that happened 11 hours before when an improvised device exploded in a garbage can near the course of a charity race
that was about to start in a small town on the Jersey Shore. That
device went off around 9:30 a.m. near the boardwalk in Seaside Park,
N.J., according to the Ocean County sheriff, Michael G. Mastronardy.
There
were no injuries. The race, the Seaside Semper Five, a five-kilometer
run and charity event along the waterfront that raises money for members
of the United States Marine Corps and their families, was canceled.
Subscribe to:
Posts (Atom)
সুরা কাহফ: ঢাল ও আলোকবর্তিকা
আল্লাহ তায়ালা মুসলিমদের জন্য বিভিন্নভাবে বিশেষ নেয়ামত ও ফজিলত দান করেছেন। কখনো বিশেষ কোনো দিনকে, কখনো কোনো সময়কে, কখনো কোনো আমলকে এবং কখনো ক...
-
F.B.I. Opened Inquiry Into Whether Trump Was Secretly Working on Behalf of Russia Following President Trump’s firing of James B. Com...
-
Fired Officer Is Indicted in Breonna Taylor Case; Protesters Wanted Stronger Charges A former officer was charged with “wanton endangermen...
-
আল-আকসা ভেঙে থার্ড টেম্পল নির্মাণের প্রচারণায় ইসরায়েল ফিলিস্তিনের মু...






